Pengtao Cao, In Abaqus, an integration point is a location within an element where the primary variables are solved. These points are used to numerically integrate the constitutive response of the element. The number and location of integration points depend on the element type and the integration technique used. For example, full integration elements typically use multiple integration points, while reduced integration elements use fewer points. Integration points are not the same as material points. Material points are used to describe solution-dependent material properties, whereas integration points are used to solve the constitutive response of the element.
There is an Abaqus "utility routine" called GETVRM. The routine can be used with output variable key (or 'VAR') set equal to IVOL to retrieve the integration point volume.
For example, if you have predicted a density of some quantity at the integration point, the total amount of that quantity in the part of the element around the integration point will equal the density multiplied by IVOL.
Pengtao Cao, In finite element analysis, elements are discretized into smaller regions for numerical integration. Each element contains several integration points where the field variables (such as stress, strain, and displacement) are evaluated.
To access the integration point volume in an Abaqus subroutine, you typically need to use the User Subroutine Interface provided by Abaqus. The specific subroutine and method depend on the type of analysis and the specific requirements of your simulation.