Ingenieurgesellschaft für
technische Software

PERMAS Changelog

INTES delivers a new PERMAS and VISPER version to all customers about every two years. Between these major releases, improvements and bug fixes are continuously released.

We encourage our customers to subscribe to the Technical Newsletter, which informes about every two months by e-mail about improvements, extensions and known problems in PERMAS and VISPER .

In addition, the PERMAS Technical Bulletin informs about known errors and improvements on a daily basis.

Version 19 (July 2022)

Short description: PERMAS_V19_short_Des_E.pdf
Detailed information: infoE_v19.pdf

Overview:
  • A new class of nonlinear dynamic problems may be simulated with the new HBM module.
  • The new LIFE module provides functionality to compute fatigue problems in PERMAS. This function is fully integrated and highly compute efficient.
  • A new interface to SIMDRIVE3D is available.
  • Performance improvements in dynamics, contact analysis and fluid-structure coupling.
  • Data model for parametric geometry.
  • Advanced input of mathematical functions.
  • Revision and extension of MPCs.
  • Automatic handling of contact rigid body modes.
  • Contact geometry update may be selected manually. The contact pressure computation has been improved.
  • Improved handling of rigid body modes in dynaic analysis.
  • Calculation of dissipated damping energy.
  • Various improvements for timehistory, random response, fscoupled analyses.
  • Support of anisotropic plasticity for short fibre materials.
  • Fitting of hyper-elastic material data for usage of measurement data.
  • Element filter for buckling sensitivity.
  • Stress scaling by filling ratios for Topology Optimization.

Version 18 (July 2020)

Short description: PERMAS_V18_Short_Des_E.pdf
Detailed information: permas_v18_prod_E.pdf

Overview:
  • The iterative solver for frequency response analysis has been accelerated significantly. Moreover, the SOLV=SMW option has been generalized, e.g. to support control elements.
  • The runtime for contact analysis of large models has been reduced once again.
  • The nonlinear stress computation is now parallelized, as well as capacity and conductivity for heat transfer.
  • Besides Kepler, also Pascal and Volta graphic cards are supported by the PERMAS Module XPU.
  • The HDF import of VisPER has been significantly accelerated.
  • The CAMG module, a new generation of contact solvers enables high performance gains for larger contact and/or structural mechanics models. Model sizes with more than 180 Mio dofs have been computed.
  • The new NLSA module provides functionality to compute large strain problems (hyperelastic material behavior).
  • MPCs may be defined also in the CONSTRAINTS variant.
  • New MPC NODE with general coupling directions.
  • Automatic over-constrained handling of MPCs and MPC labels.
  • The inertia relief command has been extended by non-moving reference as COG or for the chosen rigid body modes definitions.
  • requency dependent loads may be specified as prescribed accelerations/velocities.
  • For modal timehistory response, initial displacements and velocities may be defined.
  • The equivalent viscous damping for modal timehistory response may be computed for each eigenfrequency instead of using a constant reference frequency.
  • Nonlinear computation of transversly isotropic short fibre materials.
  • Improved stability of MPC-Update for nonlinear analyses.
  • Output out-of-balance forces and displacements for the investigatio of convergence problems.
  • New solver for linear bucling with automatic shift, also in combination with optimization.
  • Extensions to Parametric Design Optimization and Topology Optimization.

Version 17 (June 2018)

Detailed information: permas-v17-prod-E.pdf

Overview:
  • NVH analyses using MLDR and frequency response analysis for large models and high number of modes were accelerated significantly.
  • The runtime for contact analysis of large models could be again reduced. Here, a sustained speed-up factor of more than 62 on 112 cores over the complete run could be observed.
  • By ongoing parallelization, element stress and strain calculations now show improved speed-up for large models and models with many right-hand sides in linear analyses.
  • A new module GINR for a generalized inertia relief method has been introduced, which was used a couple of years by selected users only. It allows to take into account an additional stiffness matrix, which is typically derived from aerodynamic loading on a body. This additional stiffness is expected as an input quantity.
  • The list of supported Nvidia Tesla graphic cards in PERMAS Module XPU has been extended. Now, K20, K40, K80 with CUDA 7.7, 8.0, 9.0 as well as P100 with CUDA 8.0 are possible. The CUDA library is now statically linked and the user needs Nvidia drivers only.
  • The concept of local coordinate systems has been extended by systems describing a helix and a bolt thread.
  • A new implementation of Smooth Patch Recovery Method published by Zienkiewicz improves the alternative stress calculation.
  • For a given node set a node can be generated in the input of PERMAS at the barycenter of the set. This can be useful for the definition of MPC conditions like rigid regions.
  • Contact systems are now extended to support explicit local reference systems on contact surfaces.
  • For cast iron plasticity, improved convergence and stability was achieved.
  • The interpolation scheme for temperature dependent plasticity has been smoothed in order to get improved convergence.
  • The combination of nonlinear static analysis of a rotor with an eigenvalue analysis using cyclic symmetry analysis is enabled.
  • A shift option for the stiffness matrix has been added to selectively analyze a certain range of buckling factors.
  • A Coleman transformation or Multi-Blade Coordinate transformation (MBC transformation) has been added for rotating cyclic symmetric structures.
  • The calculation of additional static modes shapes is now done for all subcompoents.
  • For visco-elastic material in dynamics, a method based on Prony series has been introduced.
  • Now also the skew symmetric part of the pressure stiffness may be used in dynamic response analyses and complex eigenvalue analyses.
  • The modal random response analysis for FS coupled analyses is now available.
  • Topology optimization is used to apply free sizing to laminate structures in order to get ply shapes from the optimized thickness distributions. This reflects the fact that for a ply stack under given fiber angles not all plies are needed over the entire structure to bear the loads. The result will specify the element sets which need to have a certain ply of the ply stack.
  • Sizing of laminates is now supported, where ply thicknesses and angles can be optimized.
  • Ply failure criteria may be used as constraints for the laminate sizing optimization.

Version 16 (June 2016)

Detailed information: permas-v16-prod-E.pdf

Overview:
  • The I/O performance was imptroved further with emphasis on SSD systems.
  • An interface to the casting simulation software ADSTEFAN is now available.
  • The concept of local coordinate systems has been extended to support a larger variety of coordinate system types.
  • For surfaces with quadratic elements, a linearization is available, which makes the midside nodes linearly dependent on the corner nodes. If these surfaces are used in contact definitions, then the surfaces will also provide contact pressure results. A special export item allows to visualize the surface definitions. Definition and visualization of surfaces are fully supported by VisPER.
  • Multilinear kinematic constraints for surfaces (by MPC conditions) provide a new projection feature, where the dependent node coordinates can be modified to place them on the surface. Alternatively, a rigid lever arm will be used between the dependent nodes and the surface.
  • For the PERMAS results export, a binary format has been introduced based on the widely used HDF5 library (see https://www.hdfgroup.org/HDF5/). The main effect of this binary format is the reduction of time needed to export the results. In addition, a slight reduction of file size is achieved compared to the gzipped ASCII export file format used so far.
  • In order to reduce the number of samples without losing information about parameter influence a new sampling method (i.e. LHC Latin Hypercube Sampling) has been developed.
  • A new method for the simulation of press fit connection wa developed that works for static and dynamic analyses as well as other analysis types..
  • In surface-to-surface contacts, more contacts are taken into account than in surface-to-node contacts. In order to get the best out of a contact analysis by spending only moderately more computation time, an optional automatism has been developed, which reduces the number of contacts in surface-to-surface contact areas in a way that the accuracy is preserved..
  • A new gap function is available for contact analyses, where a given gap may be scaled by a user-defined function, which may depend on the position in space and topological information.
  • The existing post-buckling feature has been improved by enhancements of the solid shell elements and a newly implemented arc length method. In addition, a linear buckling analysis can be performed after each converged nonlinear load step.
  • It is now possible to switch automatically from linear shell elements to nonlinear solid shell elements dependent on the analysis type used.
  • The performance of geometrically nonlinear analysis has been improved by reducing the number of automatic load steps and iterations.
  • A new parallelized complex eigenvalue solver has been developed.
  • Faster Craig-Bampton mass and damping reduction.
  • Temperature-dependent stiffness is taken into account.
  • In order to support a subsequent response analysis, assembled situations and static mode shapes are considered. Also static modes due to inertia loads from inertia relief analysis can be used.
  • An explicit inversion of the system matrix for complex eigenvalues may be performed, applying the Shermann-Morisson-Woodbury (SMW) formulation. This new SMW solver is much faster than the general solver for modal frequency response analysis.
  • Modal random response analysis has now better numerical stability and the generation of cross spectral densities was improved.
  • The direct time integration for the response in time domain for fluids only is now available.
  • Due to a harmonization of the optimizers now any combination of topology, sizing, and shape optimization can be used simultaneously in one single multi-modal optimization (MMO).
  • A new additional solver Adapted Convex Programming (ACP) solver has been added to the list of optimization solvers. This out-of-core and parallelized solver is recommended for large optimization tasks, nonlinear behavior, and complex manufacturing conditions.
  • Optimization has been equipped with a general break/restart facility. Before restart, optimization parameters can be modified to influence the convergence behavior of the optimization.
  • The use of external tools in optimization loops is now possible. First examples are used to calculate safety factors, which are used as objective or constraint in a free-form optimization.
  • An arbitrary number of design coinstraints may now be declared as design objective in optimization. The maximum value will be minimized, whereas all others become constraints.
  • For multi-objective design optimization a Pareto optimization may be performed using a suitable sampling capability.
  • A new solver for the optimality criteria method with additional constraints has been developed.
  • Possible optimization objectives or constraints are weight, stress (von Mises stress, principal stress), effective plastic strain, and nodal values generated by external tools, if a local change of the part thickness influences the local value of the objective (e.g. safety factors).
  • Additional optimization constraints could be stresses outside the design area, displacements or compliance as stiffness constraints or any other constraint as long as (semi-)analytic sensitivities are available.
  • Of particular importance is the element test as additional constraint, which is used to avoid a stop of the optimization process due to failing elements.
  • The relaxation of nodes in the design area due to the thickness change is fully redesigned.
  • Release directions are available for free-form optimization as manufacturing constraint.
  • Topology optimization can now be made with multiple materials in design area.
  • Topology optimization can be used for free sizing of geometrical properties (e.g. sheet thicknesses).
  • Special improvements for frequency response optimization made this optimization task much faster.
  • A new Global Design Centering (GDC) option for optimization has been implemented. This option has been developed to search for a domain with maximum stability. A typical example application is brake squeal analysis with stochastic parameters for brake pad material.
  • A new gasket element formulation has been introduced. Now, at common nodes gasket elements with different materials can be inserted and a split of the gasket areas with different material properties is not necessary any more.

Version 15 (June 2014)

Detailed information: permas-v15-prod-E.pdf

Overview:
  • The new module XPU supports Nvidia GPU acceleration cards (Tesla K20/40 with CUDA Version 6) by a seamless integration in PERMAS parallelization concept. The acceleration will be most beneficial for compute-bound analysis, such as eigenvalue analysis with a high number of modes, a direct fluid-structure coupled response analysis, or large normal contact problems.
  • The reordering process has been improved and parallelized which reduces the run time for large models significantly.
  • Improved algorithm for direct fluid-structure coupled frequency response analysis.
  • Performance improvements are made for contact analysis in case of friction.
  • Further acceleration of compute-bound analyses by utilizing Nvidia Tesla GPUs (K20c or better) in addition to standard SMP parallelization.
  • In order to investigate the influence of certain parameters of a model on the results, a new sampling analysis feature has been integrated.
  • Self contact is now supported by contact analysis, i.e. contact models where a surface may get in touch with itself, e.g. due to warping or other forms of large deformations, and where contacting regions are not known in advance.
  • A new family of compensation springs (also called zero force springs) has been introduced, where the spring force is compensated by an additional contact force. By this means, a force-guided contact is facilitated.
  • For the linearization of contacts to perform a subsequent linear analysis (like vibration analysis), various thresholds for the locking of contacts are available. E.g., the locking can be made dependent on a threshold of the contact pressure.
  • Contact geometry update has been made more stable and faster.
  • The solver for nonlinear static analysis has been extended to take temperature-dependent material into account.
  • A new post-buckling feature has been integrated. This allows the static analysis beyond buckling. In addition, after nonlinear analysis a linear buckling can be performed to study all possible buckling modes at this point of loading.
  • Geometrically nonlinear calculations can now be also made for composite and sandwich materials . This includes buckling and post-buckling capabilities.
  • Nonstructural masses can be assigned to solid elements. Beside absolute mass values, mass per volume can also be specified.
  • Additional matrices like geometrical stiffness can now also be taken into account in dynamic modal analysis.
  • Additional static mode shapes can now be additionally taken into account in the top component of a modal analysis.
  • Backtransformation after complex eigenvalue analysis can be reduced to a subset of modes.
  • Modal response analysis in time and frequency domain can be used to provide loading matrices to enhance matrix models.
  • Coupled vibration analysis and modal coupled frequency response analysis support automatic substructuring and results in the top component.
  • Additional static mode shapes can now be additionally taken into account in an acoustic analysis.
  • A new non-parametric optimization feature has been integrated which allows a free-form shape optimization of structures for minimizing stresses by homogenization or for limiting stresses at minimum weight. This opens the most easy way to define shape optimization of free-form geometries. The set-up of this optimization is supported by a new freeshape wizard in VisPER..
  • Design constraint linking has been introduced as powerful tool to build constraint equations for multiple result values.
  • Topology optimization is now able to provide a solution with clear separation of filled and void elements. So, elements will show filling ratios near 0 or near 1. This feature avoids misinterpretation of topology optimization results and facilitates the direct use of the result for further analysis and design steps.
  • Optimization is now also possible for complex eigenvalue analysis (including rotating structures).
  • Design constraint linking has been introduced as powerful tool to build constraint equations for multiple result values..
  • Reliability analysis is now also possible for complex eigenvalue analysis (including rotating structures).
  • A zero force spring family of elements has been introduced to be solely applied in conjunction with contact analysis. The elements can support rigid body modes, but no spring force disturbs the contact force result.
  • Linear load elements and linear 3D shell elements now provide pressure stiffness as additional stiffness effect.
  • For the linearization of surfaces which consists of element faces with quadratic shape functions, a new kinematic constraint (ISURFLIN) is available. This feature can be used e.g. to linearize surfaces in case of contact.
  • For the interpolation of values in a volume, a new kinematic constraint is available (IVOLUME). This can be used e.g. for the generation of results at points where no element nodes are available.

Version 14 (June 2012)

Detailed information: permas-v14-prod-E.pdf

Overview:
  • For contact analysis where larger relative displacements between the contact partners have to be considered, a new module CAU (Contact Geometry Update) for contact geometry update has been developed. This feature works with linear and nonlinear static analysis.
  • A new interface to ABAQUS is available which allows to translate an ABAQUS model description (on .inp file) to PERMAS. VisPER is used to directly visualize the model and to identify such parts of the model which could not be translated.
  • For steady-state response analysis run times have been reduced drastically for a large number of responses in one single job. This enables high scalability for parallelization on SMP machines.
  • Eigenvalue analysis for large models with a huge number of eigenfrequencies (> 10,000) has been accelerated significantly by applying a new shift method.
  • In addition, performance and scalability of eigenvalue analysis has been generally improved.
  • By applying a new method in optimization, run times could be reduced, e.g. very drastically for bead generation.
  • More than 256 GB of memory can now be used (on Linux) which may reduce the I/O during a run and the elapsed run time.
  • Support for reading and printing of Unicode UTF-8 characters.
  • Element stresses can be generated for element sets only.
  • Load summaries were extended and comprise now cutting forces, external loads, and reaction forces. In addition, node sets and reference points may be freely defined. The summaries can also be evaluated using XY diagrams (e.g. with PERMASgraph).
  • If different materials in a model have different limits of maximum allowed stress, an automatic evaluation tool is provided which scales element results to become values of 1 for the limit values. During post-processing, this makes it easy to see the critical areas having result values larger than 1 and to identify non-critical areas having result values smaller or equal to 1.
  • Gasket elements are now managed through contact controlled nonlinear gasket analysis (CCNG analysis) by default.
  • The integration of gasket material curves has been refined for more accurate results.
  • Contact pressure can now be generated also for the deformed geometry.
  • A prescribed re-tightening of pretension and contacts is now possible, i.e. the elongation of bolts or the gap width of contacts can be changed after force locking (i.e. the combination of force and displacement controlled pretension can be used in one single load history).
  • The radiation solution for problematic model regions like close exchange surfaces with pointed sharp edges has been improved. Now, the model coarsening level has almost no influence any more on the radiation flux along the plate surfaces. In addition, two different integration methods are implemented, a general fast method for distant exchange surfaces and an accurate adaptive refinement scheme for almost singular integrands at close surface parts.
  • Nonstructural masses can be assigned to elements or element sets. Beside absolute mass values, mass per area and mass per length can also be specified.
  • A new shift method has been introduced in dynamic eigenvalue analysis to faster cope with a large number of modes.
  • Dynamic condensation using Craig-Bampton method has been extended to a Mixed-Boundary Craig-Bampton condensation (MBCB condensation) which supports also unconstrained substructure eigenmodes. Additional static mode shapes may be specified as well (i.e. inertia relief modes).
  • Frequency dependent stiffness and viscous damping can be taken into account with modified element CONTROL6 for frequency and time-history response analysis.
  • Dynamic analysis of machine tools has been extended to stability analysis for turning machines with a special force model for the interaction between tool and workpiece.
  • Modal participation factors from dynamic modal response analysis can be limited by a maximum mode number.
  • Modal participation factors can be evaluated using XY diagrams (e.g. with PERMASgraph).
  • The sensitivity computation has been revised with better performance which gives a major benefit for bead design.
  • An improved bead design variable filter results in smoother and more distinct bead patterns.
  • New design constraints are available for nodal stresses, effective plastic strains, and sound radiation power densities.
  • Another design constraint was added for the PERMAS element test, i.e. the PERMAS element test is mapped to a continuous variable with values between 0. (i.e. perfect element) and 1. (i.e. erroneous element). E.g., using this design variable in bead design will avoid the failure of the optimization loop due to collapsing elements.
  • Hull generation and smoothing as typically used for topology optimization can now also be used for shape optimization.
  • A new method is available to consistently realize minimum membersize.
  • The formulation of release directions has been improved for smoother results especially on non-uniform meshes.
  • With new solution options in module AOS maximum member size in topology optimization is now exactly formulated.
  • Sound radiation power densities and their sum over a surface set can be used as design constraint.
  • A modified CONTROL6 element is available which provides frequency-dependent stiffness and damping for eigenvalue analysis, frequency response and random response analysis. Rotation speed dependent stiffness and viscous damping can be used for complex eigenvalue analysis. With a specified reference frequency or rotation speed, a time-history response analysis or dynamic condensation can also be performed.

Version 13 (July 2010)

Detailed information: permas-v13-infoE.pdf

Overview:
  • In order to provide more optimization methods a new module AOS (Advanced Optimization Solvers) has been created. It contains additional derivative based methods but also derivative free methods as well as globalized and global methods. With these new methods it is now possible to optimize nonlinear analysis tasks like contact problems or nonlinear material analysis. Global methods can be used to optimize highly nonlinear optimization problems, where derivative based methods fail.
  • A new interface to AVL EXCITE is available.
  • A new interface to Altair's MotionSolve is also available.
  • Gasket elements are now handled by contact analysis instead of nonlinear material algorithm (leading to run time reduction by a factor of larger than 10, if no other material nonlinearities are present).
  • Contact analysis with normal contacts only or with normal and frictional contacts shows run time reductions of up to 40 percent.
  • A new eigenvalue solver kernel shows significantly improved performance for a larger number of eigenmodes.
  • Faster calculation of modal participation factors for a modal timehistory response analysis.
  • Iterative solver option for modal frequency response analysis (recommended for a large modal basis).
  • Improved performance and disk space reduction for direct transient temperature analysis.
  • Iterative solver option for steady-state temperature analysis.
  • Most of the names defined by the user in the input deck can now have long names (up to 40 characters). These include names for materials, components, variants, situations, geometrical data, sets, contacts, parts, pretensions. Some of these names can be further described using a free text, like contacts, parts, and pretensions.
  • A user stop file is provided to explicitly break iterative procedures without losing already computed results, like contact analysis, nonlinear static analysis, nonlinear heat transfer analysis, or optimization.
  • A special comment feature supports improved communication with SDM (Simulation Data Management) systems. These comments provide a means to describe any entity in the model description in any desired level of detail. To this end, the comments can be included in the model input file or the comments are linked to an additional file which also can include XML documents.
  • Gasket elements can now be handled as integral part of the contact iteration instead of a feature in nonlinear material analysis. If no other material nonlinearities are present in the model, run time reduction factors can be higher than 10 (e.g. for analysis of combustion engines with pretension, temperature loads, and cylinder pressures). In cases, where other material nonlinearities are present in the model, a run time reduction by a factor of about 2 can still be achieved.
  • Information on gap widths is now available as scalar result for the normal gap width and as tangential slip vector for frictional degrees of freedom.
  • Contact locking was extended to couple frictional degrees of freedom even in cases where friction was not taken into account during contact analysis.
  • Initial conditions (e.g. from casting) can be described as initial strains (without displacements) in nonlinear analysis.
  • User defined material laws can be used. User subroutines allow the incorporation of own material laws. The subroutine does the necessary calculation of stresses and strains together with the tangent matrix associated with the material law.
  • Extrapolation of stresses for linear and nonlinear elements is now fully provided. For linear elements, stresses are calculated at the stress points and either assigned or extrapolated to the element corner nodes. For nonlinear elements, stresses are calculated at the integration points and either assigned to the element nodes or extrapolated to the element corner nodes. If stresses are not assigned to the element midside nodes, these stresses will be calculated through linear interpolation from the element corner nodes. In plasticity analysis, stresses at the element nodes are showing stresses at the integration points or they are showing extrapolated stresses which do not lie on the yield surface any more. In case of subsequent generation of nodal point stresses in post-processing, the original element stress results can be seriously modified.
  • Modelling of damping was extended to any component including subcomponents by Rayleigh damping and component structural damping. In subcomponents, damping is applied to Guyan as well as Craig-Bampton reduced parts. This type of damping can also be used with fluid-structure coupled analysis.
  • In addition, modal damping can be specified by a modal damping matrix. The input of matrix elements can be as viscous damping ratio, damping value, or material damping coefficient. The modal damping matrix may be diagonal, symmetric, or non-symmetric. The modal damping matrix is applicable to systems with modal degrees of freedom including Craig-Bampton modes.
  • For rotating structures, any number of rotational speeds is now defined in a separate input. A reference rotational velocity is used in the static pre-run. From this pre-run, additional matrices are built for the reference rotational velocity. The specified rotational velocities are used to scale the additional matrices during dynamic response analysis. This procedure makes response analysis of rotating structures very efficient.
  • New design elements for shape optimization, bead design, and free coordinate modifications are available. Shape optimization is supported for any arbitrarily shaped design space, with an arbitrary number and location of design nodes, and with a smooth interpolation between design spaces (and boundary). Bead design supports automatic generation of bead design variables according to a user-defined reference.
  • Shape optimization and bead design can always be combined with sizing optimization.
  • Contact analysis results are available as new design constraints: contact pressure, contact reaction forces, and contact gap widths.
  • Heat flux results from heat transfer analysis is available as new design constraint.
  • Material parameters are available as design variables in optimization.
  • In Topology Optimization (module TOPO) a fixed mold parting line can be defined for opposite release directions.
  • In Reliability Analysis (module RA) material parameters can now be used in the same way as for optimization.
  • For a number of input data, PERMAS can generate postscript files using gnuplot (if gnuplot is available on the currently used machine). It will generate gnuplot command files, and a table with the xy-data of the curves will be exported to a file. Such input data include load history, material curves for plasticity, and transient loads in timehistory response analysis.

Version 12 (July 2008)

Overview:
  • Improved reordering algorithm.
  • New storage scheme for sparse matrices and faster matrix operations.
  • Large improvements for contact analyses with friction.
  • Faster direct frequency response for coupled FS analyses.
  • Much faster modal frequency response for fluid analyses or coupled FS calculations using an iterative solver option.
  • Faster matrix input (in ASCII and binary format).
  • Energy computation is now possible without elemental displacements.
  • The new module NLD is an entry point to nonlinear dynamics supporting transient analysis under material nonlinearities, where large translations of elastic bodies are taken into account.
  • Bolt pretension: A generalized concept for pretension of bolts has been implemented. Beside the classical approach using a cutting plane with pretension in normal direction, a new approach using cylindrical thread coupling with pretension in axial direction is available. This highly innovative feature offers a convenient definition which can take into account the detailed effects of radial spreading and axial torque caused by the thread's flank and pitch geometry without the need of modeling the flank shape or thread line explicitly.
  • Cyclic symmetry: cyclic symmetric structures can now be handled directly for static analysis with matching cyclic symmetric loads and real eigenvalue analysis (see modules LS and DEVX). There, the analysis of the whole structure is replaced by a series of analysis for one sector with different boundary conditions.
  • Rotor dynamics is improved in the inertial reference frame. The rotating axisymmetric structure can now be elastic. Hence, additional gyroscopic and stiffness terms are provided. As with the co-rotating reference frame an automatic sweep to get a Campbell diagram is available.
  • Generation and use of matrix models has been improved for static and dynamic applications. Beside the generation of damping on subcomponent level, additional options are available to facilitate the backtransformation of results.
  • A calculated contact state can be locked for subsequent analyses. This locking leads to a linearization of the contact problem around the current contact state. To achieve this, the active contacts are transformed to kinematic constraints. With this new model various kinds of subsequent analyses are possible (like eigenvalue analysis, heat transfer analysis, or submodeling).
  • Additional contact results are automatically provided for the evaluation of saturation and declination of frictional forces, for the verification of pretension definitions, pretension directions, and pretension threads (like flank normal, downhill and pitch direction), and for the evaluation of pretension coupling forces.
  • For efficient calculation of successive contact variants new contact status files are available for easy job recovery and considerable run time reductions.
  • For the calculation of slip forces, prescribed constant velocities can be specified for subsequent friction analysis by module CAX.
  • A new analysis feature allows to perform a material nonlinear analysis of inertia relief cases.
  • A new solver (following the approach of Thomas) is available which accelerates the nonlinear analysis under certain conditions.
  • Nonlinear static analysis is possible using substructuring.
  • A new viscoplastic material is available.
  • Additional results are provided for the verification of initial strains and element temperatures.
  • An automatic surface coarsening procedure supports computation of viewing factors in heat exchange by radiation for very large models (with millions of radiation elements; see module NLHT).
  • Generalized modal condensation is available to establish system matrices in modal space for external applications.
  • A new solver option for modal time history analysis is available: The Newmark beta algorithm is extended to HHT (Hilber-Hughes-Taylor) algorithm. This algorithm introduces an algorithmic damping effect which increases with frequency.
  • Addtional static mode shapes can now be specified in subcomponents, too (see static mode shapes in module DRA). In assembled situations additional static mode shapes can be applied for multiple loading conditions in modal frequency response analysis and will lead to much shorter run times for large mode sets.
  • Linear heat transfer is supported with convectivity coefficient as design parameter and temperature as new design constraint.
  • Incompatible meshes are also supported and allow the optimization of supports in static and dynamic analysis without mesh modifications.
  • Shape optimization has been simplified by specifying surface normals as optimization directions.
  • A minimum wall thickness for release directions can be used to keep a box closed.
  • Symmetry conditions for planar, axial, and cyclic symmetry are supported.
  • A new filter is available which allows for maximum membersize definitions.
  • Reliability analysis can now be used with contact analysis and load history. Also, modal frequency response analysis can be used with reliability analysis.
  • A new linear control element with eight nodes is available.
  • Fluid-structure coupling elements can now be used to provide the result item sound radiation power density.
  • Solid elements (in 3D), gasket elements, line and point plot elements may have geometrical properties assigned which allows for a more convenient model handling in post-processors that need property data for a model partitioning.

Version 11 (July 2006)

Overview:
  • The MLDR solver for FS applications, a new parallel FS Eigenvalue solver kernel, faster reordering algorithms, assembly situations for modal frequency response, faster and more stable convergence for contact problems and improved performance for material nonlinear analysis are the main features to enhance performance.
  • The new proprietary PERMAS license server provides flexible license management.
  • PERMAS now fully supports 64 Bit architecture of modern processors in the following execution modes: D32: double precision floating point operations on 32 Bit machine words, memory usage of about 2 GB, D64: double precision floating point operations on 32 Bit machine words, memory usage of about 8 GB, S64: single precision floating point operations on 64 Bit machine words, practically unlimited memory usage.
  • Weldspots: The new WLDS model improves accuracy of the force and displacement results and reduces mesh sensitivity.
  • Extended Contact Aanalysis: Provides high performance algorithms for large contact models and a new nonlinear iterative solver for critical slip-stick problems.
  • Submodelling: transfer results of a global model as boundary conditions for a remeshed submodel.
  • Error indicator: supporting mesh refinement.
  • Extended contact analysis: direct computation of contact pressure and shear in the contact surface, frictional energy, full support for inertia relief.
  • Assembly situations: much faster solution for large mode sets with multiple loading conditions in modal frequency response (modules DRA and FS).
  • Fourier analysis: transformation of time dependent loads of a periodic process to the frequency domain..
  • Residual iteration: improved time step stability for time integration with discrete nonlinear elements (module DRA).
  • Random Response: modal random response analysis (module DRX).
  • Fluid-structure coupling: fast MLDR method for vibration analysis of large models with many modes.
  • Follower loads: nonlinearities pressure, temperature and inertia loads enhance the combined material and geometrical analysis (module NLS).
  • Substructuring: now also available in nonlinear statics.
  • Heat exchange by radiation: including view factor computation, now available in nonlinear heat transfer (module NLHT).
  • Extended Optimization: frequency dependent constraint limits and frequency dependent weighting of design objective, optimization of correlation between given and computed frequency response, optimization of actively controlled systems including the control element parameters, support of modal frequency response analysis, release directions are supported as manufacturing constraints.
  • Compressed input/output: the .gzip format can be directly processed by PERMAS.
  • LOADA: new family of membrane elements for the application of loads and the evaluation of stresses at the surface.
  • CON: extension of the family of convection elements to include radiation effects and viewing factor computation.
  • X1MOB1: new scalar fluid element to facilitate the specification of supports for fluid meshes.

Version 10 (June 2004)

Overview:
  • MLDR (Multilevel Dynamic Reduction): fast eigenvalue solver for large models and a large number of eigenvalues.
  • NLHT Nonlineat Heat Transfer: new nonlinear solver for steady state and transient analyses.
  • NLSMAT (Extended nonlinear material laws): cast iron and nonlinear hardening.
  • H3D (Hyperview postprocessing Interface).
  • VLAB: Virtual Lab Integration.
  • VAO: PERMAS-VAO Interface.
  • Faster and more stable algorithm for contact analysis.
  • Improved performance for parallelization.
  • News Gasket Elements .
  • Linear control elements CONTRL5, CONTRL10.
  • Quadratic elements for heat transfer.
  • Standard cross-sections for beam elements including stress computation with support for optimazation.
  • Performance improvements for MPCs.

Version 9 (June 2002)

Detailed information: infoE_V09.pdf

Overview:
  • Dynamic condensation with the module Extended Dynamic Eigenvalue Analysis.
  • New DADS interface.
  • New SIMPACK interface.
  • Contact with pretension.
  • Combined geometric and material nonlinearities.
  • Steady state results in time domain derived from frequency response.
  • Support of frequency constraints in module TOPO (.
  • Combination of reliability analysis and optimization for a robust design.
  • Incompatible connection of shell elements with volume elements.
  • XY data in coordinate directions.
  • Distributed element loads as a function of coordinates.
  • Data line generation in PERMAS input.
  • New shell family for linear and nonlinear applications with 3 and 4 nodes for linear shape functions and 6, 8, and 9 nodes for quadratic shape functions. These elements are using a 3-dimensional shell formulation and are designed to work for material non-linearities.
  • New HEXE8 element using the EAS (Enhanced Assumed Strain) formulation with 9 or 21 extended strain modes. This element is available in addition to the previous HEXE8 element.
  • New TET10 element improving the use of TET meshes in contact analysis. This element is available in addition to the previous TET10 element.
  • New general beam elements with and without warping allowing one intermediate cross section between the two nodes of the element.
  • New axisymmetric shell element with corresponding uid element, coupling element, and wave element.
  • In addition to the already existing linear plot elements, the corresponding quadratic plot elements have been implemented.

Version 8 (June 2000)

Overview:
  • DRX: Extended dynamic response analysis.
  • TOPO: Topology or layout optimization .
  • Incompatible meshes for shell models.
  • Automated Spotweld Modeling.
  • Contact with incompatible meshes.
  • Direct frequency response for module FS and new elements for radiating boundary conditions (RBC).
  • Support of dynamic frequencies in module OPT.
  • Derivative based methods (FORM/SORM) and response surface methods in module RA.

Version 7 (June 1998)

Overview:
  • Improved stress extrapolation for membrane elements and modified integration scheme.
  • Load pattern combinations for static and heat transfer analysis.
  • Parallelization on shared memory architectures.
  • Generation and output of internal forces by option CUTTING FORCE.
  • Extended model size limits.
  • New renumbering option HFSMLMF (default). Due to our experience, HFSMLMF should be superior in ordering quality and memory consumption.
  • Reduced postprocessing results with the option ERES = CORNER.
  • Extended selection option in data export.
  • Extended Convergence information.
  • support of CATIA 4.20 and of automated coupling of model parts.
  • Temperatures of a thermal calculation may be applied as structural loads by a special menu.

Version 6 (June 1996)

Overview:
  • Parallelization on distributed memory architectures.
  • New module NLS (Nonlinear Static Analysis) enables the calculation of large displacements.
  • The PATRAN interface has been revised and now offers a complete exchange of the model and results.
  • New interface to ADAMS multibody dynamics simulation.
  • Integration in the CATIA CAD system.
  • Extension of the fluid structure coupling.

Version 5 (November 1993)

Overview:
  • Complete revision of the software basis.
  • NASTRAN Interface - PERMAS can import and process NASTRAN data sets directly.
  • New interface to MEDINA.
  • New interface to IDEAS.
  • Extension of the fluid structure coupling.

Version 4 (July 1991)

Overview:
  • Design Optimization with new Module OPT.
  • New Module RA for reliability analysis.
  • New Module LA for the analysis od laminate materials.
  • Support of new Hardware (IBM RS/6000, HP 9000).

Version 3 (July 1989)

Overview:
  • New hyperfront solver boost performance and increases the possible problem size.
  • Expanding the number of nodes to more than 65,000 in each substructure.
  • New Module FS for fluid-structure coupling.
  • Support of the CRAY-2 supercomputer with UNICOS operating system and 2GB memory.
  • Support of the AMDAHL supercomputer utilizing vector computing and parallel I/O.
  • Support of the IBM ES/3090 with Vector Facility.

Version 2 (July 1987)

Overview:
  • New User Control Interface (UCI) for more flexible and user-friendly handling.
  • A new family of triangular shell elements is now fully compatible with the QUAD4 elements.
  • Extension of modal frequency response to structural damping with different coefficients for each mode.
  • Heat transfer through radiation both for transient response and direct integration.
  • Generalized Multilinear Constraints.
  • Support of new Hardware (Apolllo Domain, CONVEX, Honeywell-Bull SPS-9, IBM ES/3090 with up to 256MB memory).

Version 1 (1985)

After purchasing the FEM software system ASKA from the University of Stuttgart, which has been developed in the academic environment since 1967, INTES starts to to completely revise the software and to upgrade it for use in an industrial environment. The new system is introduced under the name PERMAS.
Overview:
  • Installation on various computer systems (Cray-1, IBM 3081, CD Cyber 170, PRIME 750, UNIVAC 1100, , VAX-11).
  • Standard APC programs for the most important applications in statics, dynamics, plasticity, creep, buckling, heat transfer.
  • The new software PERMIT realizes a standardized interface between PERMAS and the pre/post processing systems PATRAN, I-DEAS and CAEDS as well as STRIM100.
  • Complete revision of the documentation.