xPSD: An External Solver to Compute Linear Responses to Random Base Excitations (PSD) in Structures Using ANSYS with the Large Mass Method
It is sometimes desirable to incorporate one's own solver with a finite element model created using commercial finite element software. ANSYS facilitates such efforts through the use of User-Defined Features  (UDF's) and the ANSYS Application Programmers Interface (API). This paper summarizes one such application developed by the authors for a customer with very specific needs in the calculation of structural response to random base excitations. The software solution described in this report differs substantially with the PSD random vibration solver offered by ANSYS Inc. in several respects - both in theoretical approach taken and program architecture. The net result offers the user a reduction in computer storage requirements and calculation speed for the analysis of structures subjected to a single random base excitation.