The Jacobian (i.e., stiffness) matrix used in the full Newton technique to solve nonlinear problems. The quasi-Newton technique is an alternative solution approach that can be less expensive than the default full Newton technique. The difference between the two approaches lies in the number of times that the Jacobian is reformed. The quasi-Newton technique reforms this matrix less often than the full Newton method, allowing for the possibility of a faster solution. The user has no control over how often the Jacobian is reformed in the full Newton technique, whereas with the quasi-Newton approach this can be adjusted. The kernel matrix is the mathematical derivation of the quasi-Newton technique, in which the kernel matrix is an approximate representation of the inverse of the full Jacobian.
For more information:An input option in Abaqus/Standard, Abaqus/Explicit, and Abaqus/CFD that indicates the kind of data definitions specified in option blocks. For example, if you want to use a particular material in an analysis, you must add an option block beginning with the keyword *MATERIAL to the input file. Keywords are always preceded by an asterisk and appear in uppercase characters in the Abaqus documentation.
For more information:The first line of an option block in an Abaqus input file. Keyword lines begin with a particular keyword, followed, in some cases, by parameters associated with the keyword. For example, the keyword line of an option block describing a material might appear as *MATERIAL, NAME=name. In this case *MATERIAL is the keyword and NAME is a parameter that allows you to specify the name of the material being defined.
For more information:Words or phrases on a keyword line that are used to define the behavior of an option. Parameters can stand alone or have a value, and they may be required or optional. An example is the keyword parameter TYPE used with the keyword *ELEMENT to specify what type of element (such as solid, beam, or shell) is being defined. See also input parameter to learn how input parameters are used in Abaqus/Design.