3.11.1 Design sensitivity analysis

Product: ABAQUS/Design  

I. Basic procedure tests for continuum elements

Elements tested

CPE3    CPE3H    CPE4    CPE4H    CPE4H    CPE4I    CPE4IH    CPE4R    CPE4RH    CPE6    CPE6H    CPE6M    CPE6MH    CPE8    CPE8H    CPE8R    CPE8RH   

CPS3    CPS4    CPS4I    CPS4R    CPS6    CPS6M    CPS8    CPS8R   

CPEG3    CPEG3H    CPEG4    CPEG4H    CPEG4I    CPEG4IH    CPEG4R    CPEG4RH    CPEG6    CPEG8    CPEG8H    CPEG8R    CPEG8RH   

C3D4    C3D4H    C3D6    C3D6H    C3D8    C3D8H    C3D8I    C3D8IH    C3D8R    C3D8RH    C3D10    C3D10H    C3D10M    C3D10MH    C3D15    C3D15H    C3D20    C3D20H    C3D20R    C3D15V    C3D15VH    C3D27    C3D27H    C3D27R    C3D27RH   

CAX3    CAX3H    CAX4    CAX4H    CAX4I    CAX4IH    CAX4R    CAX4RH    CAX6    CAX6H    CAX6M    CAX6MH    CAX8    CAX8H    CAX8R    CAX8RH   

CGAX3    CGAX3H    CGAX4    CGAX4H    CGAX4R    CGAX4RH    CGAX6    CGAX6H    CGAX8    CGAX8H    CGAX8R    CGAX8RH   

Features tested

This section includes a general set of simple tests to verify the design sensitivity analysis (DSA) technique for stress/displacement continuum elements for static steps. Geometrically linear and nonlinear tests are done for both total and incremental DSA formulations. In addition, selected problems also test static perturbation steps and frequency steps. A full range of design parameters is used, including those related to sizing (e.g., material properties, thickness) and shape (i.e., nodal coordinates). The results verified are primarily displacement sensitivities for static steps and eigenvalue sensitivities for frequency steps.

Problem description

All problems are one- or two-element models with elastic or hyperelastic material properties. The models are fixed at one end and loaded using displacements, point loads, or distributed loads at the opposite end. At least one material property and one nodal coordinate are used as design parameters for each test; a sizing parameter, such as thickness, is also used as a design parameter if appropriate for the particular model.

Results and discussion

All sensitivity results are verified by comparison to hand calculations or to overall finite difference results.

Input files

pdsatotcpe.inp

Total DSA with plane strain stress/displacement elements.

pdsainccpe.inp

Incremental DSA with plane strain stress/displacement elements.

pdsatotcps.inp

Total DSA with plane stress stress/displacement elements.

pdsainccps.inp

Incremental DSA with plane stress stress/displacement elements.

pdsatotcpeg.inp

Total DSA with generalized plane strain stress/displacement elements.

pdsainccpeg.inp

Incremental DSA with generalized plane strain stress/displacement elements.

pdsatotc3d.inp

Total DSA with three-dimensional stress/displacement continuum elements.

pdsaincc3d.inp

Incremental DSA with three-dimensional stress/displacement continuum elements; includes frequency step.

pdsatotcax.inp

Total DSA with axisymmetric stress/displacement continuum elements; includes frequency step.

pdsainccax.inp

Incremental DSA with axisymmetric stress/displacement continuum elements.

pdsatotcgax.inp

Total DSA with axisymmetric stress/displacement elements with twist.

pdsainccgax.inp

Incremental DSA with axisymmetric stress/displacement elements with twist.

II. Basic procedure tests for structural elements

Elements tested

B21    B21H    B22    B22H    B23    B23H    B31    B31H    B31OS    B31OSH   

B32    B32H    B32OS    B32OSH    B33    B33H   

M3D3    M3D4    M3D4R    M3D6    M3D8    M3D8R    M3D9    M3D9R   

MAX1    MAX2    MGAX1    MGAX2   

S4R    S4R5    S4    S3R    STRI3    S8R    S8R5    S9R5    STRI65   

SAX1    SAX2    SAXA14    SAXA24   

T2D2    T2D2H    T2D3    T2D3H    T3D2    T3D2H    T3D3    T3D3H   

Features tested

This section includes a general set of simple tests to verify the design sensitivity analysis (DSA) technique for membrane and shell elements. Geometrically linear and nonlinear tests are done for both total and incremental DSA formulations. A full range of design parameters is used, including those related to sizing (e.g., material properties, thickness) and shape (i.e., nodal coordinates). All problems test static steps, and some selected problems also test frequency steps.

Problem description

All problems are two-element models with elastic or composite material properties. The models are fixed at one end and loaded using displacements, point loads, or distributed loads at the opposite end. At least one material property and one nodal coordinate are used as design parameters for each test; a sizing parameter, such as thickness, is also used as a design parameter if appropriate for the particular model.

Results and discussion

All sensitivity results are verified by comparison to hand calculations or to overall finite difference results.

Input files

pdsatottruss.inp

Total DSA with truss elements.

pdsainctruss.inp

Incremental DSA with truss elements; includes frequency step.

pdsatotm3d.inp

Total DSA with membrane elements.

pdsaincm3d.inp

Incremental DSA with membrane elements; includes frequency step.

pdsatotmax.inp

Total DSA with axisymmetric membrane elements.

pdsaincmax.inp

Incremental DSA with axisymmetric membrane elements.

pdsatotmaxa.inp

Total DSA with axisymmetric membrane elements with twist.

pdsaincmaxa.inp

Incremental DSA with axisymmetric membrane elements with twist.

pdsaincbeam.inp

Incremental DSA with beam elements.

pdsatots3d.inp

Total DSA with shell elements; includes frequency step.

pdsaincs3d.inp

Incremental DSA with shell elements; includes frequency step.

pdsatotsax.inp

Total DSA with axisymmetric shell elements; includes frequency step.

pdsaincsax.inp

Incremental DSA with axisymmetric shell elements.

pdsatotsaxa.inp

Total DSA with axisymmetric shell elements with asymmetric deformations.

pdsaincsaxa.inp

Incremental DSA with axisymmetric shell elements with asymmetric deformations.

pdsatotbeam.inp

Total DSA with beam elements.

III. Basic procedure tests for special-purpose elements

Elements tested

GK2D2    GK2D2N    GKPS4    GKPS4N    GKPS6    GKPS6N    GKAX2    GKAX2N    GKAX4   

GKAX4N    GKAX6    GKAX6N    GKPE4    GKPE6   

GK3D2    GK3D2N    GK3D4L    GK3D4LN    GK3D8    GK3D8N    GK3D6    GK3D6N   

GK3D18    GK3D12M    GK3D18N    GK3D12MN   

Features tested

This section includes a general set of simple tests to verify the design sensitivity analysis (DSA) technique for gasket elements. Geometrically nonlinear tests are done for both total and incremental DSA formulations.

Problem description

All problems are static problems with gaskets sandwiched between continuum elements. The design parameters chosen govern the gasket section properties.

Results and discussion

The results are verified by comparing them with the results from the overall finite difference method.

Input files

pdsainctwogasket.inp

Incremental DSA with two-dimensional gasket elements.

pdsatottwogasket.inp

Total DSA with two-dimensional gasket elements.

pdsaincthreegasket.inp

Incremental DSA with three-dimensional gasket elements.

pdsatotthreegasket.inp

Total DSA with three-dimensional gasket elements.

IV. Elastic material verification tests

Elements tested

CPE4I    CAX4    C3D8    S4R   

Features tested

This section includes simple tests to verify DSA for the isotropic elasticity, hyperelasticity (Ogden and polynomial models), and hyperfoam material options. The elastic material models are tested as geometrically linear cases that include temperature dependence. The hyperelastic models are tested as geometrically nonlinear cases with the material properties input as coefficients (no test data input). The material coefficients are chosen as the design parameters. For all problems sensitivities of element and node responses are verified for static steps, and for selected problems sensitivities of eigenvalues and eigenfrequencies are verified for frequency steps.

Problem description

The tests are performed on a square or a cylindrical block discretized with four to eight elements. The block is held fixed at one end and loaded using prescribed displacements or point loads at the other end. Key material coefficients used in defining the material models are the primary design parameters, while some shape parameters are made design parameters as appropriate.

Results and discussion

All response sensitivities are verified by comparison to overall finite difference results.

Input files

mdsatotaxel.inp

Total DSA, elastic axisymmetric model.

mdsatotaxelt.inp

Total DSA, elastic axisymmetric model with temperature dependence.

mdsatot3del.inp

Total DSA, elastic three-dimensional model.

mdsatot3delt.inp

Total DSA, elastic three-dimensional model with temperature dependence.

mdsainc2dhyp.inp

Incremental DSA, hyperelastic (polynomial) two-dimensional model.

mdsainc3dhyp.inp

Incremental DSA, hyperelastic (polynomial) three-dimensional model.

mdsainc2dhyo.inp

Incremental DSA, hyperelastic (Ogden) two-dimensional model.

mdsainc3dhyo.inp

Incremental DSA, hyperelastic (Ogden) three-dimensional model.

mdsainc2dhyf.inp

Incremental DSA, hyperfoam two-dimensional model; includes frequency step.

mdsainc3dhyf.inp

Incremental DSA, hyperfoam three-dimensional model.

mdsaoritrs.inp

Incremental DSA, elastic with engineering constant model, shell element with orientation.

V. Contact verification tests

Elements tested

C3D8    C3D10M    CPE4    CPE6M    S4R   

Features tested

This section includes a set of simple tests to verify DSA for contact between solid displacement elements and rigid surfaces with small-sliding and finite-sliding surface interaction. Both analytical and discrete rigid surfaces are used. The interaction between the rigid and deformable surfaces is assumed to be frictionless for all small-sliding surface interactions. Isotropic Coulomb friction with a friction coefficient of 0.2 is assumed for the finite-sliding tests. Two-dimensional and three-dimensional first-order solids with hyperelastic material models are tested. Shape parameters that affect the slave surface and friction coefficient are chosen as the design parameters, and the sensitivities of the contact responses CPRESS and CDISP are verified.

Problem description

The tests are performed on a square block discretized with four to eight elements. The structure is held fixed at one end, and a rigid die is pushed onto the other end using prescribed displacements. The incremental DSA formulation is used in all tests. Shape parameters that change the shape of the slave surface are chosen as the primary design parameters.

Results and discussion

The response sensitivities are verified by comparison to overall finite difference results.

Input files

idsaincsm2d_arig.inp

Incremental DSA, small-sliding, two-dimensional model, analytical rigid surface.

idsaincsm2d_arig_surf.inp

Incremental DSA, small-sliding, two-dimensional model, analytical rigid surface, surface-to-surface constraint enforcement method.

idsaincsm2d_drig.inp

Incremental DSA, small-sliding, two-dimensional model, discrete rigid surface.

idsaincsm2d_drig_surf.inp

Incremental DSA, small-sliding, two-dimensional model, discrete rigid surface, surface-to-surface constraint enforcement method.

idsaincsm2dm_arig.inp

Incremental DSA, small-sliding, two-dimensional model, modified triangles, analytical rigid surface.

idsaincsm2dm_arig_surf.inp

Incremental DSA, small-sliding, two-dimensional model, modified triangles, analytical rigid surface, surface-to-surface constraint enforcement method.

idsaincsm3d_arig.inp

Incremental DSA, small-sliding, three-dimensional model, analytical rigid surface.

idsaincsm3d_arig_surf.inp

Incremental DSA, small-sliding, three-dimensional model, analytical rigid surface, surface-to-surface constraint enforcement method.

idsaincsm3d_drig.inp

Incremental DSA, small-sliding, three-dimensional model, discrete rigid surface.

idsaincsm3d_drig_surf.inp

Incremental DSA, small-sliding, three-dimensional model, discrete rigid surface, surface-to-surface constraint enforcement method.

idsaincsm3dm_arig.inp

Incremental DSA, small-sliding, three-dimensional model, modified tetrahedra, analytical rigid surfaces.

idsaincsm3dm_arig_surf.inp

Incremental DSA, small-sliding, three-dimensional model, modified tetrahedra, analytical rigid surfaces, surface-to-surface constraint enforcement method.

idsainc2d_arig.inp

Incremental DSA, finite-sliding, two-dimensional model, analytical rigid surface with friction.

idsatot2d_arig.inp

Total DSA, finite-sliding, two-dimensional model, analytical rigid surface with friction.

idsainc2d_drig.inp

Incremental DSA, finite-sliding, two-dimensional model, discrete rigid surface with friction.

idsatot2d_drig.inp

Total DSA, finite-sliding, two-dimensional model, discrete rigid surface with friction.

idsainc3d_arig.inp

Incremental DSA, finite-sliding, three-dimensional model, analytical rigid surface with friction.

idsatot3d_arig.inp

Total DSA, finite-sliding, three-dimensional model, analytical rigid surface.

idsainc3d_drig.inp

Incremental DSA, finite-sliding, three-dimensional model, discrete rigid surface with friction.

idsatot3d_drig.inp

Total DSA, finite-sliding, three-dimensional model, discrete rigid surface.

idsaincshell.inp

Incremental DSA, finite-sliding, structural model, analytical rigid surface with friction.

VI. Miscellaneous tests

Features tested

This section includes various tests used to verify the behavior of the *DSA CONTROLS option. Output variables, unsupported elements, and restart are also verified.

Problem description

Elements are subjected to concentrated or distributed loads. Static analyses are performed.

Results and discussion

The response sensitivities are verified by comparison to overall finite difference results.

Input files

cdsatotpar.inp

Total DSA testing user perturbation size control.

cdsaincpar.inp

Incremental DSA testing user perturbation size, gravity loading, and mass sensitivity controls.

cdsatottol.inp

Total DSA testing sizing frequency and tolerance controls.

cdsainctol.inp

Incremental DSA testing sizing frequency and tolerance controls.

cdsaunspele.inp

Incremental DSA testing unsupported elements (beam, spring, gasket, and connector elements with the supported C3D8 element).

mdsaoritrs_static_restart.inp

Restart static analysis with DSA.

mdsaoritrs_frequency_restart.inp

Restart frequency analysis with DSA.

cdsaincpar_restart.inp

Restart nonlinear frequency analysis with DSA.

cdsaincload.inp

Incremental DSA with design-dependent concentrated loads.

cdsatotload.inp

Total DSA with design-dependent concentrated loads.