4.1.24 VDLOAD: nonuniform loads

Product: ABAQUS/Explicit  

I. Nonuniform body forces

Elements tested

CPE3    CPE4R    CPS3    CPS4R    CAX3    CAX4R    C3D4    C3D6    C3D8R   

M3D3    M3D4R    SAX1    S3R    S4R    T2D2    T3D2   

Features tested

Nonuniform body forces.

Problem description

In this verification test all the available element types are tested by loading them with a nonuniform body force. All the element nodes are fixed in position, and the reaction forces generated at the nodes are used to verify the element load calculations. The purpose of this test is to verify the element load calculations, not to test all the capabilities of user subroutine VDLOAD.

The material model is isotropic linear elasticity. The material properties used are defined as follows: Young's modulus = 193.1 × 109, Poisson's ratio = 0.3, and density = 785.

In the first step a nonuniform body force of 1.0 × 105 is applied in the x-direction for all the elements except the axisymmetric elements, where it is applied in the r-direction. The amplitude function for this nonuniform body force is defined such that the load is ramped on over the first half of the step and held constant for the rest of the analysis. In the second step another nonuniform body force of 1.0 × 105 is applied in the y-direction for all the elements except the axisymmetric elements, where it is applied in the z-direction. This load is applied using the same amplitude function that was used in the first step. For C3D4, C3D6, C3D8R, S3R, S4R, M3D3, and M3D4R elements, another nonuniform body force of 1.0 × 105 is applied in the z-direction in a third step. This load also has the same amplitude function that was used in the first step.

Results and discussion

The results for all of the elements agree with the analytical values, which are included at the top of the input file.

Input files

element_nbody.inp

Input data used for this test.

element_nbody.f

User subroutine used for this test.

II. Nonuniform pressure load

Elements tested

*DLOAD option
B21    B31    CPE3    CPE4R    CPS3    CPS4R    CAX3    CAX4R    C3D4    C3D6    C3D8R    M3D3    M3D4R    R2D2    RAX2    R3D3    R3D4    SAX1    S3R    S4R   

*DSLOAD option
CPE3    CPE4R    CPS3    CPS4R    CAX3    CAX4R    C3D4    C3D6    C3D8R    M3D3    M3D4R    R2D2    RAX2    R3D3    R3D4    SAX1    S3R    S4R   

Features tested

Nonuniform pressure load prescribed with the *DLOAD and *DSLOAD options.

Problem description

In this verification test all the available element types are tested by loading them with a nonuniform pressure load. All the element nodes are fixed in position, and the reaction forces generated at the nodes are used to verify the element load calculations. The purpose of this test is to verify the element load calculations, not to test all the capabilities of user subroutine VDLOAD.

The material model is isotropic linear elasticity. The material properties used are defined as follows: Young's modulus = 193.1 × 109, Poisson's ratio = 0.3, and density = 785.

In the first step a nonuniform pressure of 1.0 × 105 is applied on element edges (for CPE3, CPE4R, CPS3, CPS4R, CAX3, CAX4R, SAX1, R2D2, and RAX2 elements) or element faces (for C3D4, C3D6, C3D8R, S3R, S4R, M3D3, M3D4R, R3D3, and R3D4 elements). For the beam elements (B21 and B31) a nonuniform force per unit length of 1.0 × 105 is applied in the y-direction. The amplitude function for this nonuniform pressure load is defined such that the load is ramped on over the first half of the step and held constant for the rest of the analysis. In the second step a nonuniform pressure of 1.0 × 105 is applied on a different element edge (for CPE3, CPE4R, CPS3, CPS4R, CAX3, and CAX4R elements) or element face (for C3D4, C3D6, and C3D8R elements). For the beam elements (B21 and B31) a nonuniform force per unit length of 1.0 × 105 is applied in the x-direction. These loads are applied using the same amplitude function that was used in the first step.

Results and discussion

The results for all of the elements agree with the analytical values, which are included at the top of the input file.

Input files

element_npres.inp

Input data for element-based loads used for this test.

surface_npres.inp

Input data for surface-based loads used for this test.

element_npres.f

User subroutine used for this test.