I am attempting to create a 27-node solid 3D user-defined element with the LS-Dyna object code. However, it appears to me that the object code is hard coded in many, many places for 8-node solid elements. For example in the dyn21usld.f file and then in the usrsld() subroutine, the main subroutine the calls the user-defined element subroutine, declares the bmtrx variable as:<\/p>\n
common\/bel7loc\/bmtrx(nlq,3,3,8*(3+NXDOFUE))<\/p>\n
where (based on my interpretation):<\/p>\n
nlq – number of elements in current block<\/p>\n
3,3 – matrix of shape function derivatives<\/p>\n
8*(3+NXDOFUE) – number of nodes,8, times the number of degrees of freedom per node<\/p>\n
This matrix is hard coded in many places throughout the dyn21usld.f file. Also, this is just one example of the hard coded nature of an 8-noded element there are also other variables such as the bvec array, as well as, do-loops that appear to be hard-coded for 8-nodes. <\/p>\n
Q1: Can user-defined elements be developed with more than 8-nodes per element? <\/p>\n
Q2: Does that require tracing through all the places where an 8-node element is assumed? <\/p>\n
Q3: Is there an easier way to develop a user-defined element with more than 8-nodes rather than finding all the places where it is hard-coded?<\/p>\n
Q4: How will the rest of the program know how many nodes are being used for the element? <\/p>\n
Q5: Am I correctly interpreting that at least some of the variables and do-loops are hard-coded for 8-node solid elements? <\/p>\n
<\/p>\n
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