## Archive for June, 2012

#### Model Calibration Using Optimization Techniques

06/27/2012

 Fatma Koçer-Poyraz -  Director of Business Development

Introduction:

When we think of optimization, we naturally think of finding the design with minimum cost, maximum performance, etc. However, we can use optimization methods for objectives other than minimizing or maximizing. One of these use cases is to meet a set of target values; so we need neither to minimize a response nor maximize it. We instead need to make sure that it achieves the target value.

A typical application comprises model calibration problems, such as simulation material model calibration to match to test data. We can formulate these cases as minimizing the difference between sets of data leading us down the path to use optimization methods for efficient and effective solution- finding.  How we calculate the difference may depend on the application, but a very common calculation that works well for most problems is to minimize the sum of normalized-difference-squared. Another common calculation may involve calculating the area between two curves.

The first aspect of solving such problems easily is the method selection. The second aspect is the ease of setup, and the third aspect is the post-processing. In HyperStudy, we have an objective function formulation called System Identification. System identification allows users to set target values to a number of responses and automatically creates the difference equation and uses it as the objective function. In the pos- processing site, HyperStudy lists the values of all objectives, the delta between them, and the targets and the normalized deltas. We will now go through an application that uses system identification for material model calibration. (more…)

#### Learning Spotlight: HyperStudy

06/26/2012

This short video demonstrates an effective process of calibrating multiple models using design of experiments (DoE) and optimization methods in HyperStudy. We applied this process to calibrate a ductile aluminum alloy modeled in RADIOSS block as an elasto-plastic material using Johnson-Cook model to match to test data.

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#### NASA: A Safer Landing with Water Impact Analysis

06/26/2012

Using Altair’s own HyperWorks virtual simulation suite, Altair ProductDesign built an accurate finite element model of the module from CAD data supplied by NASA, as well as a section of water and air which matched the conditions from the lake used during the physical tests. The effect on the module’s structure during impact was simulated to gauge how well the results correlated with the physical tests. The results showed excellent correlation between the simulation and physical tests, identifying areas where the model, input parameters and meshing methods could be improved to give a more accurate prediction of the event.

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#### Anaglyph Furthers Relationship With Altair by Adding its Composite and Laminate Analysis Software to Altair’s HyperWorks Partner Alliance

06/26/2012

HyperWorks users now can access CoDA and LAP through the partner program with their HyperWorks licenses

The Laminate Analysis Program (LAP) is used to analyze any type of composite laminate.  Typically, the software is used in the preliminary design for tailoring a stacking sequence, then analyzing the composite component with other methods, such as FE, and finally optimizing the design by inspecting the laminate behavior layer by layer. CoDA synthesizes the properties of composite layers or laminates to be used in a seamless manner within the design modules. This integration allows for instantaneous assessment of the effect of changes on any input parameters. CoDA also provides “what-if” scenarios for users to rapidly evaluate graphically any output result as a function of variable input data. Altair HyperWorks customers can now access CoDA and LAP through the HWPA with their existing HyperWorks units.

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#### Product Updates – June 2012

06/26/2012

SimLab 11.0 Released

SimLab V11.0 contains many new  features and enhancements for solver interface, Performance improvements in handling large models & Node matching Assembly etc.

It also  includes a new simplified Volume Mesher user interface, upgrade to latest version of Parasolid and Abaqus libraries.

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06/26/2012

## Topic details:

Frequency Response Analysis is used to calculate the response of a structure subject to steady state oscillatory excitation. Typical applications are NVH (Noise, Vibration and Harshness) analyses of vehicles, rotating machinery and transmissions. The analysis is to compute the response of the structure, which is actually transient, in a static frequency domain. The loading is sinusoidal. The loads can be forces, displacements, velocity and acceleration. The response occurs at the same frequency and damping would lead to a phase shift. The outputs from a frequency response analysis are displacements, velocities, accelerations, forces, stresses and strains. The responses are usually complex numbers that are either given as magnitude and phase angle or as real and imaginary part.

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#### Map Thickness from Geometry to FE Model

06/26/2012

Topic details:
The new Mid-Mesh Thickness utility allows the automatic mapping of thickness from any legacy geometry to a representative FE model.

There are several options to control how the thicknesses are applied to nodes, elements or properties plus auto-correction factors are available for complex use cases.

Currently the tool is available for RADIOSS (Block), OptiStruct, Abaqus, LS-DYNA, and Nastran user profiles.

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