OptiStruct is a proven, modern structural solver with comprehensive, accurate and scalable solutions for linear and nonlinear
analyses across statics and dynamics, vibrations, acoustics, fatigue, heat transfer, and multiphysics disciplines.
The OptiStruct Example Guide is a collection of solved examples for various solution sequences and optimization types and provides
you with examples of the real-world applications and capabilities of OptiStruct.
This section presents nonlinear small displacement analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
Structure quarter symmetric pipe model with pretension bolt and a gasket seal, demonstrates the usage of gasket material
and gasket seal specific results for diagnostics.
The structural analyses of a cylinder head under various loading conditions can be accomplished by means of finite element
analysis using OptiStruct. The results, combined with each analysis concerning the different operating processes of the engine, can be separated
mainly into two parts.
This section presents nonlinear large displacement analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
This section presents nonlinear transient analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
This section presents normal modes analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
This section presents complex eigenvalue analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
This section presents thermal and heat transfer analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
This section presents analysis technique examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
This section presents shape optimization example problems, solved using OptiStruct. Each example uses a problem description, execution procedures and results to demonstrate how OptiStruct is used in shape optimization.
The examples in this section demonstrate how topography optimization generates both bead reinforcements in stamped
plate structures and rib reinforcements for solid structures.
The examples in this section demonstrate how the Equivalent Static Load Method (ESLM) can be used for the optimization
of flexible bodies in multibody systems.
This section presents multiphysic examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
This section presents response spectrum examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
This section presents nonlinear explicit analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
The OptiStruct Example Guide is a collection of solved examples for various solution sequences and optimization types and provides
you with examples of the real-world applications and capabilities of OptiStruct.
This section presents nonlinear small displacement analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
The structural analyses of a cylinder head under various loading conditions can be accomplished by means of finite element
analysis using OptiStruct. The results, combined with each analysis concerning the different operating processes of the engine, can be separated
mainly into two parts.
The structural analyses of a cylinder head under various loading conditions can be
accomplished by means of finite element analysis using OptiStruct.
The results, combined with each analysis concerning the different operating processes of the
engine, can be separated mainly into two parts.
The capacity of gasket sealing mainly depends upon the pre-stressing of the bolts, which
are the source of the maximum external loading on the inner structure of the cylinder
head.
The location of the weakest contact pressure on the raised portion of the gasket can be
transferred as a result of the effect of thermal stress or strain, which may cause the
increase in pressure and escaping of the gas.
Based on the above use case, Nonlinear Static Analysis is demonstrated for the Altair inline-four engine block model, as shown in Figure 1. The key features such as 3D pretension bolts, gasket material
modeling, friction contact and bore deformations are highlighted.
Note: There are a few
orphan grids in the model, which may lead to some differences in contour results when the
H3D results are plotted in HyperView. If results are different
from what is illustrated in this document, then mask the orphan grids in HyperView and then plot the contour again.
The analytical procedure could further be divided
into three load steps by means of the superposition principle for simulating various
operating processes of the engine, so the structural analysis are composed of the outputs of
these three load steps.
FE Model
Element Types
CHEXA
CTETRA
The linear material properties are:
MAT1
Young’s Modulus
21500 MPA
Poisson's Ratio
0.3
MGASK
Direct Tensile Modulus
0.001
Transverse Shear Modulus
12000
Assembly Loadings
The major percentage of the loading applied to the engine is the assembly loading.
This mainly refers to the pre-stressing of the bolts, and it plays an important role in
preventing gas from escaping from the internal part of the engine.
Thermal Loadings
In the case of thermal loadings, the nodal temperatures resulting from the prescribed
thermal analysis are assigned to all corresponding nodes of the FEM model of the second
cylinder head in order to calculate the thermal stress/strain of the cylinder head
structure.
The gas pressure created as a result of the firing of the spark plug is imposed on the
surface of the combustion chamber. However, the magnitude of the gas pressure varies with
different durations of the cycle. For the steady-state analysis, the average gas pressure is
introduced into the loading conditions for the simulation here.
The nonlinear static
analysis material properties are:
Case 1
Assembly Loadings
Applied pretension loading (41.25 KN) in head bolts