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Top News:

We are here for you!
2020-03-23

We all are facing an extraordinary situation.

We have reduced our physical office presence in combination with home office in order to protect the health of our employees and to guarantee at the same time the quality of our services.

It is important for us to keep economy alive and to minimize the consequences of this crisis, as far as possible.

This also includes advancing our joint projects and to continue to ensure your operational safety and to be well equipped for the future.

Therefore, we ensure our services for you, so that you are able to stay productive:

-All contact partners of our company are available via the well-known communication channels, regardless whether they are on site or working in the home office.

-Our support is fully available by phone, e-mail and our ticket system.

-We offer training by video-conferencing.

Should you face new process or IT challenges due to the current situation, we are happy to help you. Unusual situations require creative solutions. We can help you with that.

We wish you, your families and your company the best - please stay healthy.

Sincerely, your INTES team

Invitation to attend the PERMAS Users' Conference
2020-01-24

Since the current development of the corona pandemic continues to be dynamic, we have, with a heavy heart, no choice but to cancel the PERMAS Users´Conference 2020 for the benefit of all.

--

The original news:

The invitation to attend the PERMAS Users' Conference on April 23 - 24, 2020 in Stuttgart is online now.

The PERMAS Users' Conference will take place at the Filderhalle in Leinfelden-Echterdingen near Stuttgart. After a reconstruction, there is a modern convention hall at a beautiful location.

New Workshops - Register Now!
2020-01-16

English training courses for PERMAS are arranged on an individual basis. Therefore we offer the courses at any time convenient to you, provided that an instructor is available. We need to know about the date 8 weeks in advance for planning. So please suggest a date that suits you. Usually, the training takes place in our office in Stuttgart.

Please note that the language for the regular courses listed on the training page is German and that they take place in Stuttgart unless denoted differently.

We would be pleased to advise you on the ideal selection of training courses.

Organisation and information:
Claudia Krauss
Tel.: +49 711 78499-0
E-Mail: Claudia.Krauss@intes.de

PERMAS to Simulate System Behavior of Milling Machines
2018-10-24
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A milling machine model with simulation results of circularity test,
stability chart generation, and response to a sudden jump.

The dynamic behavior of a complete machine tool including tools and workpieces is crucial for the development of such machines. The accuracy of the motion of tables and tools is absolutely essential for the accurate resulting surface shape of the workpieces. Fast positioning and fast machining are important, the first with very small to no vibrations and the latter with high cutting depths and no chatter.

The complete system comprises structural parts, drives of the various axes, their control, and rotating spindles. During the interaction of tool and workpiece, the dynamic forces are causing vibrations of the machine, which have to be damped out sufficiently by all system components. Finally, the machine tool should provide highest accuracy and cutting depth at high speed.

The FE (Finite Element) method is the standard method for numerical vibration analysis in many application fields. So, it is quite natural to use this method for complete machine tools. To this end, PERMAS contains control elements, which are prepared to model a typical machine control with displacement control, velocity control, and current control. In addition, other elements are used for spindle supports, which allow the modeling of speed-dependent stiffness and damping.

With all of these modeling features, PERMAS performs all dynamic analysis methods like real and complex eigenvalue analysis, frequency response analysis, and time-history response analysis. In particular, a numerical stability analysis of machine tools is available to predict stable process parameters and chatter frequencies.

The attached picture shows a milling machine model with simulation results of circularity test, stability chart generation, and response to a sudden jump.

The circulatory test is achieved by a time-history response analysis of a given table move starting at no speed using a limited jerk condition. The resulting move is almost a circle and shows very small deviations.

The response to a sudden jump is also calculated by a time-history response analysis, where the given table move is a sudden jump in X direction.

The stability chart is calculated with a force model for the interaction between tool and workpiece. The upper diagram shows the dependency of stable cutting depth on the spindle speed with the milling cutter. There, the maximum cutting depth for a stable process also depends on the rotating direction. The lower diagram contains the chatter frequencies dependent also on the spindle speed and its rotating direction.

Also turning machines can be analyzed in a similar way (see here).

PERMAS® is making realistic simulations practical. PERMAS® supports advanced product designs through effective and rapid optimization of complex situations. PERMAS® is an integrated FE analysis software combining thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS®, a Short Description is available. More detailed information may be obtained from the Product Description.

PERMAS in the Cloud - A Cooperation of T-Systems and INTES
2018-09-21
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In CAE applications, flexible use of computer power is getting more important for many users. To meet this demand for PERMAS, T-Systems and INTES have concluded an agreement, which allows T-Systems to provide PERMAS to the users of the Open Telekom Cloud.

The Open Telekom Cloud, the public cloud product of Telekom, is available as hybrid cloud solution - and provides more security and higher speed on demand. In this way, the computing and storage capacities can be used on the certified and highly secured computing centers of Telekom in Saxony-Anhalt. On the other hand, enterprises may use the proven cloud resources also on dedicated hardware exclusively. This hardware can be placed in the computing centers of Telekom, which is used by enterprises through a secure connection, or Telekom installs the servers needed directly at the customers site.

INTES provides PERMAS with the pre- and post-processor VisPER with all functions on the Open Telekom Cloud. Users have greatest flexibility to use any PERMAS functions. In particular, this holds for the use of optimization, parameter studies, or reliability analysis, which will increase the demand for computing power considerably in the coming years. The highly performant implementation in PERMAS provides a very efficient use of cloud resources for such applications. Within the hardware capabilites provided, also the parallelization of PERMAS can be flexibly used, and compute-intensive jobs are run with highest performance.

"We are convinced that the use of PERMAS in the cloud is an important extension of our offering.", Reinhard Helfrich, Chief International Officer of INTES, said. "The easy access to resources, the efficient use, and the high security build the basis for an extension of CAE applications in enterprises. In this way, the importance of simulations in product development will grow significantly."

Because security aspects play a prominent role in cloud utilization, IT resources based on the open standard OpenStack may be also used by those enterprises, which are not using public cloud services. Enterprises may use the Open Telekom Cloud locally on dedicated systems abroad, either due to compliance or latency reasons. The certified Open Telekom Cloud fulfils the requirements of the European General Data Protection Regulation (GDPR).

More information can be achieved with the link to the Telekom Cloud.

PERMAS® is making realistic simulations practical. PERMAS® provides extremely fast and accurate solutions for realistic simulations of large models and complex situations in time. PERMAS® supports better product designs through effective and rapid optimization of complex situations. PERMAS® is an integrated FE analysis software. It combines thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS®, a Short Description is available. More detailed information may be obtained from the Product Description.

Shape Optimization of Wheel Spokes to Survive Wheel Impact Test
2018-03-07
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Shape optimization with non-linear quasi-static analysis of wheel impact test
using five shape basis vectors (SBV) results in significant reduction of plastic strains.

For the homologation of alloy wheels, a number of standard tests have to be performed before such wheels are allowed to be used in cars. Such tests are bending fatigue test, radial fatigue test, and impact test. The latter test represents the inclined collision of a wheel and a curb at low speed, where the spokes are not allowed to crack. To pass this test at the first time successfully, previous numerical simulation and optimization can avoid late re-design and late start of production.

The impact test conditions describe a low speed impact on the rim, which can be handled as quasi-static analysis case. An elastic-plastic contact analysis is easily applied to compute effective plastic strains, where the results are taken after the potential energy of the falling mass is consumed by elastic and plastic deformations of the test rig with the wheel. The point of failure is defined, when the effective plastic strain exceeds the ultimate plastic strain of the material used.

When failure occurs, a shape optimization can be applied to reduce the plastic strain at the critical points. In addition, a special condition has to be fulfilled, which does not allow to make shape changes of the front view, because this is exclusively defined by the stylist. This is a very special manufacturing constraint for the optimization.

The attached picture shows the shape optimization of a wheel to survive the impact test. The initial model shows high plastic strains on the reverse side of the spokes with 11.9% and 4.9%. A parametric shape optimization of the reverse side of the spokes is performed taking the fivefold cyclic symmetry of the wheel into account. Three Shape Basis Vectors (SBV) are used for the outer radius of the spokes and two additional SBV are used for the inner radius of the spokes. The weight is used as objective and the effective plastic strain is used as constraint limited to 3.4% for the two highly strained locations on the spokes' reverse side. Convergence is achieved after three iterations with six loops each, which are used to calculate the derivatives for all five SBV for this non-linear optimization task. To reduce the plastic strains, the weight of the wheel has to be increased by 3.2%.

The set-up of the shape optimization is supported by the Shape Wizard in VisPER. Here, the SBV are specified and prepared for the later optimization with PERMAS. VisPER is also used for the result evaluation, where the history plots for constraints and objective are generated and the shape changes and resulting stress and strain fields are visualized. Additional history plots show the influence of the single SBV on the shape change.

Two animations about change of effective plastic strain and the coordinates on the reverse side of the spokes give a more detailed impression.

More details of shape optimization are described here and in the PERMAS Product Description.

PERMAS® is making realistic simulations practical. PERMAS® supports advanced product designs through effective and rapid optimization of complex situations. PERMAS® is an integrated FE analysis software combining thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS®, a Short Description is available. More detailed information may be obtained from the Product Description.

Comparison of experimental modal analysis (EMA) with dynamic eigenvalue analysis
2018-02-06
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Example of a ladder frame with measured and computed natural frequencies and mode shapes.
The MAC matrix at top right side shows strong correlation for five modes.

For structures under dynamic loads, simulations and experiments are frequently used side by side. This leads to mutual benefits. On the one hand, simulation provides a means to identify preferred points to measure. On the other hand, experimental results can be used to identify differences between experimental and simulation model, which provide a basis for model updating to fit the test results by simulation.

One important comparison between experimental modal analysis (EMA) and Dynamic EigenValue analysis (PERMAS module DEV) is between measured and computed natural frequencies and between measured and computed mode shapes. While the natural frequencies can be compared directly, the comparison of mode shapes is usually made using MAC matrices (MAC - Modal Assurance criterion). To this end, each mode shape of the experiment is compared with each computed mode shape and vice versa. The values of a MAC matrix is between Zero and One. Values near One indicate a strong similarity of the mode shapes, while small values indicate different mode shapes.

PERMAS is capable to read model and results (from a Universal File) and to use them subsequently to generate and export directly the MAC matrix with the computed mode shapes.

The attached picture shows an example, which kindly has been made available by Prof. Dr.-Ing. Jörg Bienert of Ingolstadt University of Applied Sciences. He has determined the experimental results for the ladder frame structure, while the simulation and the comparison have been made by INTES. The location of the sensors does not fit to nodes of the FE mesh. So, interpolation regions were used to connect the sensor locations with the neighboured nodes of the FE mesh. By doing so, the computed results are available at the same points as the measured results and the comparison can be performed directly by generating the corresponding MAC matrix.

For the first three modes, the computed and measured natural frequencies and mode shapes are shown. We see from the MAC matrix that the modes four to seven were not available in the experimental results. The experiment used one-dimensional sensors, which perfectly detect displacements normal to the ladder frame. But the computed modes four to seven show displacements in the plane of the ladder frame, which are not detectable by the used sensors.

More information is available about the capabilites of PERMAS to perform eigenvalue analysis, either real eigenvalue analysis, or modal condensation and complex eigenvalue analysis, or real eigenvalue analysis by Multi-Level Dynamic Reduction.

PERMAS® is making realistic simulations practical. PERMAS® supports advanced product designs through effective and rapid optimization of complex situations. PERMAS® is an integrated FE analysis software combining thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS®, a Short Description is available. More detailed information may be obtained from the Product Description.

Graphic-Based Process for Frequency Response Analysis
2017-12-18
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Model description, mode shape visualization, PERMAS job submission,
and evaluation of frequency response results with VisPER.

Frequency response analysis (FRA) as a forced vibration analysis under harmonic loading is available with PERMAS since many years. In case of a modal FRA, the eigenmodes and eigenfrequencies are calculated first and the FRA is performed in a second step. It is a frequently proven procedure to check the eigenmodes first before starting the FRA. Beside the mode shapes, strain and kinetic energy distributions and effective masses are also important to check.

In an action to facilitate the use of FRA, the application process is now supported by VisPER, the graphical user interface of PERMAS. The steps of the FRA process for a given structure are as follows:

  1. The eigenmodes and eigenfrequencies are computed and exported to the binary HDF5 formatted result file of PERMAS.
  2. VisPER is used to read and visualize the modes and frequencies.
  3. All FRA related input like damping, harmonic loads, excitation frequencies, nodes for response evaluation can be easily specified in VisPER.
  4. The PERMAS FRA job is set up in VisPER and started from within VisPER. The modes and frequencies need not to be re-calculated. Hence, the computation time is reduced accordingly.
  5. The FRA results are read and post-processed with VisPER.

Model data, mode shapes, FRA results, and generated pictures and animations can be collected in a PowerPoint, Word, or Excel file using a provided template, which can be tuned to specific requirements.

When the user checks the eigenmodes and eigenfrequencies in a post-processing step, it is quite logical to proceed with the definition of the FRA specifications in the same software. Subsequently, the FRA job can be started and FRA results can be imported in VisPER after the PERMAS job is finished. After result evaluation of the FRA, modifications of the dynamic model are supported and the FRA can be repeated in the same way.

The attached picture shows two overlapping bonded sheets with harmonic concentrated load and a node set for response results. The first two mode shapes are shown (for bending and torsion). After specifying the additional FRA input, the PERMAS frequency response analysis is started from within VisPER (screen shown bottom left). Then, the FRA results are postprocessed with VisPER (screen shown bottom right).

VisPER is the Graphical User Interface (GUI) of PERMAS. VisPER integrates pre- and post-processing functions and it allows to start PERMAS executions. Moreover a reporting facility supports the creation of reports containing model information and analysis results by pictures and animations.

PERMAS® is making realistic simulations practical. PERMAS® supports advanced product designs through effective and rapid optimization of complex situations. PERMAS® is an integrated FE analysis software combining thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS®, a Short Description is available. More detailed information may be obtained from the Product Description.

Multimodal Optimization to Design and Position Vibration Absorbers
2017-09-09
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Simply supported beam subject to harmonic pressure load

Vibration absorbers are mainly used in civil engineering, e.g. for high-rise structures and bridges. But also mechanical engineering benefits from vibration absorbers, e.g. in machine/building interaction or insulation of vibrating structures. Moreover, in case of vibrations tending to instabilities, vibration absorbers are always an important topic, e.g. brake squealing, blisk vibrations in jet engines.

Although time dependent processes are often responsible for amplifying vibration amplitudes, broad-band damping is still of great interest, because the critical frequencies are not known in advance. Therefore, we focus here on deterministic harmonic loads.

The classical means for vibration absorption are tuned mass dampers, consisting of a secondary mass, a viscous damper, and an elastic spring. They are commonly attached to a primary vibrating system for suppressing undesirable vibrations. Finding closed solutions for optimal parameters of dynamic vibration absorbers is usually limited to simple academic two-degree-of-freedom systems. However, in finite element analysis of flexible structures several modes must be damped for large structural models, a broad band of excitation frequencies has to be applied, and multiple vibration absorbers should be handled simultaneously.

The solution is a multimodal optimization with a sizing approach for the parameters of each absorber and a positioning approach of the absorbers to find the optimum location. With PERMAS, a unified approach is made, where the finite element analysis and the optimization is performed in one single software using one single finite element model. In each optimization loop, a dynamic eigenvalue analysis, a modal frequency response analysis, and an optimization step is performed. This fully integrated optimization procedure enables the user to simultaneously find optimal parameters including positions of multiple dynamic vibration absorbers in the frequency domain.

The attached picture shows a simple application case, where a supported beam is subject to a harmonic pressure load at the top surface. Three mass dampers are initially applied at the mid point, at one quarter point and at three quarters point on the bottom side of the beam.

The locations in X direction beside stiffness and damping values of all three vibration absorbers are used as design variables. The absorbers solely act in load direction. The objective of the optimization is the minimum displacement amplitude in the middle of the beam bottom side in the frequency range [0, 120] Hz. The vibration absorbers at the quarter points move towards the center point during the optimization. The displacement amplitude at the fundamental eigenfrequency of the initial configuration is reduced from 92 mm to 39 mm.

More examples of absorber optimization are presented on the previously published paper. In addition, PERMAS optimization features are also described here.

PERMAS® is making realistic simulations practical. PERMAS® supports advanced product designs through effective and rapid optimization of complex situations. PERMAS® is an integrated FE analysis software combining thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS®, a Short Description is available. More detailed information may be obtained from the Product Description.

PERMAS® on new INTEL® XEON® SCALABLE PROCESSORS
2017-07-11
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The overall performance of PERMAS® always depends on the performance of both hardware and software. The close cooperation between Intel and Intes over many years ensures the ongoing adoption of new features to be at the forefront of high performance computing. As a consequence, a new processor release is always accompanied by the best adapted software. This is exactly what INTES wants to provide to its customers.

We want to target all customers who have an increasing need for high performance FE solutions. Simulation driven design fosters this trend to more accurate simulation results. A higher accuracy is possible by using larger and more complex models.

The new INTEL® XEON® SCALABLE PROCESSORS are supported by PERMAS® from the very beginning. On these processors, PERMAS® shows excellent performance as documented on a joint flyer.
There is up to 56% higher 4-socket performance than in a previous-generation server.

The leap in performance on this new INTEL® XEON® SCALABLE PROCESSORS is mainly due to the AVX 512 instruction set, because it perfectly supports the high level matrix operations in PERMAS®. Increased memory bandwidth helps to better exploit the speed of the processors.

Large simulation models are mostly running out-of-core. A high speed storage device like Intel’s NVMe SSD drives are directly addressed by PERMAS® without the need to use an I/O controller resulting in very efficient I/O and short overall run times. In particular, short access times combined with a direct I/O scheme in PERMAS® provides high data transfer to optimally feed the processors. An additional increase of data transfer can be obtained by striped SSD drives.

Processor systems with several sockets are very suitable to increase throughput for multiple jobs, particularly in combination with high performance SSD drives.

How INTES implemented PERMAS® on this new generation of INTEL® XEON®; SCALABLE PROCESSORS is shown in an instructive movie.

PERMAS® is making realistic simulations practical. PERMAS® provides extremely fast and accurate solutions for realistic simulations of large models and complex situations in time. PERMAS® supports better product designs through effective and rapid optimization of complex situations. PERMAS® is an integrated FE analysis software. It combines thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS®, a Short Description is available. More detailed information may be obtained from the Product Description.

PERMAS computes vehicles' stressed wire harness
2017-07-05
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Model of wire harness between car body and door.
Stress results and contact pressure at a door opening of 70 degrees.

Covers and openings of vehicles usually contain electric drives and functions like adjustable and heatable exterior mirrors, window lifters, speakers, and lighting in doors. These functions need power which is supplied by wires from the battery. The wires have to allow for a wide opening of doors. This leads to high stresses in the wires which can lead to wire breakage. So, a stress analysis of wires during door opening is essential to prove a wire harness design.

The picture to the left shows an industrial example of a typical wire harness between a car body and a door. The wire consists of thirteen conductors of various diameters. A bellow is applied to protect the wire from water. While the upper end of bellow and wire are fixed at the car body, the lower ends have to follow a prescribed opening of the door by 70 degrees. The rotational axis is shown which corresponds to the hinges of the door.

The stress analysis of this wire harness mainly depends on contact:

  1. Contact between the conductors of the wire.
  2. Contact between the convolutions of the bellow at the outer side and at the inner side of the bellow.
  3. Contact between wire and the inner surface of the bellow.
The first two contacts are characterized by a greater number of bodies with potential contact between conductors and convolutions, where the real contact zones cannot be predicted easily. The most effective way of modeling these contacts is by self-contact, where the software itself looks for the current contacts between the bodies and updates the contacts as appropriate. In addition, large displacements and large rotations are taken into account, while the material is still elastic.

The lower left picture shows the nodal von Mises stresses in the wire after the rotation of 70 degrees. For the same rotation, the lower right picture shows the contact between wire and bellow by solid areas on a transparent bellow, where the solid areas show the contact pressure as a result.

Two animations about motion and stresses of the wire harness are more enlightening.

More details on contact analysis are collected in the PERMAS Product description, pp. 72 to 77.

PERMAS is making realistic simulations practical. PERMAS provides extremely fast and accurate solutions for realistic simulations of large models and complex situations in time. PERMAS supports better product designs through effective and rapid optimization of complex situations. PERMAS is an integrated FE analysis software. It combines thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS, a Short Description is available here. More detailed information may be obtained from the Product Description here.

Topology Optimization with Contact
2017-06-23
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Comparison of shapes found by topology optimization in PERMAS for different
coupling conditions between a block with quadratic bore and a bent beam.

It is a question raised often what to do with contact in topology optimization. Is it possible? Is contact as a nonlinear feature managed properly at all? What is the influence of contact on the results? Contact is the most frequently used nonlinearity and an important boundary condition. So, there is the good message that contact can be used in a standard way by topology optimization in PERMAS.

The picture to the left shows a simple example, where a block with a hole is supporting a bent beam. It is a fully solid model with contact between the beam and block hole. The initial gap between both bodies is zero. The objective of the topology optimization is the compliance and the weight constraint is to save 60 percent of the design space.

The picture shows three optimizations with three different boundary conditions:

  1. Block and beam are coupled at the common interface. So, no contact is applied.
  2. The surface of the block hole is not changed and the first layer of elements at the block hole is not changeable by the topology optimization.
  3. The surface of the block hole is changeable and the surface can be reduced where no contact is active.
All pictures are generated after a fully converged topology optimization with a clear separation of filled and void elements and a subsequent smoothing of the finally achieved surface.

The first column shows a perspective view of the topology optimization result, where the initial block size is shown in transparency. The second column shows a cut through the mid plane of the topology optimization result. The third column shows the contact status at the block hole (for cases two and three only). The contact status perfectly reflects the different shape.

The example model was inspired by the following publication: Ahmad, Z., Sultan, T., Zoppi, M., Abid, M., Park, G. J. (2016) ‘Nonlinear response topology optimization using equivalent static loads—case studies’, Engineering Optimization.

The set-up of a topology optimization with contact is very easy and particularly tailored for PERMAS by its pre- and post-processor VisPER. Contacts are defined as for every contact analysis (by using the contact wizard). Objective and constraints for the topology optimization are also defined (by using the topology optimization wizard). The final smoothed surface shape can be exported during post-processing of the results as an FE mesh or by STL format to process the result of the topology optimization further (e.g. new meshing).

More details of topology optimization are presented on the flyer published previously. It is illustrated by an industrial example. In addition, topology optimization is also described here.

PERMAS is making realistic simulations practical. PERMAS provides extremely fast and accurate solutions for realistic simulations of large models and complex situations in time. PERMAS supports better product designs through effective and rapid optimization of complex situations. PERMAS is an integrated FE analysis software. It combines thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS, a Short Description is available here. More detailed information may be obtained from the Product Description here.

PERMAS saves weight and improves endurance
2017-04-24 (Freeform Optimization)
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Freeform optimization is a method for shape optimization of Finite Element (FE) models, where the geometry of the model surface is modified while the element topology remains unchanged.

Freeform optimization is not a mathematical shape optimization method but it uses optimality criteria. They describe the relationship between a geometry change and its influence on a certain result quantity. Mainly, the relationship between a geometry change and equivalent stresses in the material is of great importance. This means that a high stress can be reduced by adding material (i.e. increase of part thickness) at the position of the high stress. The same holds for the inverse, i.e. a stress increases when part thickness is reduced.

Beside equivalent stresses all stress-like quantities like principal stresses, stress differences between different load cases, effective strains or safety factors can be used. Typical optimization solutions are stress homogenizations under weight conditions or a weight optimization under stress limits. The method is well suited for large models with many load cases and is mainly used to optimize the shape of models with free surface geometry like cast parts for housings of transmissions and engines. Applicable analysis methods are among others linear and non-linear static analysis including contact as well as frequency response analysis in dynamics.

The implementation of the method in PERMAS has now been extended by a combination with mathematical optimization methods in case of certain additional constraints, which are best represented by sensitivities. For example, this allows the limitation of displacements at bearings or an additional constraint on the compliance of the optimized structure. In dynamics, vibration amplitudes of selected nodes can also be restraint. Also, a third party software for endurance calculations can be invoked from within PERMAS in order to take its results as constraint or even objective function in a freeform optimization. By combining parametric and non-parametric optimization methods, many realistic requirements can be considered in one single optimization.

The set-up of an optimization model for freeform optimization is very easy and particularly tailored for PERMAS by its pre- and post-processor VisPER. A surface node set has to be selected only to sufficiently define the design space for freeform optimization. The related design elements are selected automatically. Stress and weight constraints as well as other constraints are very easily defined.

PERMAS freeform optimization targets to save weight and improve endurance in one single optimization. The time for development of structural parts can be significantly shortened while the structural behavior is improved by optimization.

The details of a freeform optimization is presented on the attached flyer. It is illustrated by an industrial example. More information on optimization can be found here.

PERMAS is making realistic simulations practical. PERMAS provides extremely fast and accurate solutions for realistic simulations of large models and complex situations in time. PERMAS supports better product designs through effective and rapid optimization of complex situations. PERMAS is an integrated FE analysis software. It combines thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS, a Short Description is available. More detailed information is available from the Product Description.

Topology Optimization in Dynamics
2017-03-29
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Comparison of frequency response of en engine bracket after an all static optimization (left)
and an optimization with both static and dynamic excitation (right).

Topology optimization is a standard method for shape finding under given boundary conditions and loads. Often, static load cases are used for topology optimization, because it is easy to apply and gives a good first impression of the best shape. For dynamically loaded structures, it is obvious that a topology optimization should include a dynamic analysis, too. To this end, the topology optimization method has to be extended for dynamic analysis. This extension has been developed in PERMAS to enable topology optimization to be used simultaneously for static and modal frequency response analysis.

The example of an engine bracket as shown in the picture to the left is used to show the effect of a concurrent use of static and dynamic loading in topology optimization. At the top of the picture, the design space and its boundary conditions are shown. So-called frozen regions are applied for the fixations of the part, which are not allowed to be modified during topology optimization. Release directions are also taken into account.

Below, the left column shows the optimized shape for a static load only, and the right column shows the optimized shape for a static load combined with a harmonic (sine or cosine) excitation. The weight of the optimized part is the same for both cases. The found designs are both fully converged results with a zero-one distribution of skipped (i.e. a filling ratio near zero) and remaining elements (i.e. a filling ratio near one).

The bottom of the picture compares the frequency response of the loading point for both cases. The shape found by static loading only shows a much higher amplitude when a harmonic excitation is applied compared to the other case, where the harmonic excitation has been taken into account during optimization. It can be concluded that a topology optimization under harmonic excitation urgently requires an optimizer, which can properly handle static and modal frequency response analysis simultaneously.

An animation of both optimizations over all iterations is shown here.

A paper is available on the engine bracket optimization, too.

Why you should use PERMAS for Topology Optimization in Dynamics? Although the need for a topology optimization with harmonic excitation is obvious, such a feature is not sufficiently supported in many other optimizers. The reason lies in the very nonlinear relation between small changes of structural stiffness and mass and the resulting change of frequency responses. This nonlinearity becomes very critical in case of plastics, because parts of this material show more eigenfrequencies in a typical frequency range than metal parts. Moreover, it is not sufficient to monitor the response just for one frequency, but a monitoring over the complete frequency range is required. PERMAS handles all these cases properly and provides the right means for topology optimization under harmonic excitations. PERMAS delivers a fully converged shape of the optimized parts, which is very close to the final design or can be directly used for production. By using PERMAS, dynamically loaded parts can be successfully optimized and high costs for testing and re-design of parts can be significantly reduced.

PERMAS is making realistic simulations practical. PERMAS provides extremely fast and accurate solutions for realistic simulations of large models and complex situations in time. PERMAS supports better product designs through effective and rapid optimization of complex situations. PERMAS is an integrated FE analysis software. It combines thermo-mechanics, vibro-acoustics, and design optimization. For more information on PERMAS, a Short Description is available here. More detailed information is available from the Product Description here.