COMPUTER-SIMULATION OF LARGE FRAME STRUCTURES

A weapon test canister frame provides a structural platform for a weap on device and associated diagnostic instrumentation. The underground e nvironment in which a test canister is placed results in the canister being subjected to large static loads. Excessive canister deflection u nder load may result in misalignment of optical lines-of-sight, with r esulting degradation of the quality of the experimental physics data w hich is obtained. Each weapon test costs tens of millions of dollars a nd takes months or years to design and construct, and thus it is essen tial that the canister structure maintains functionality and prevents excessive deformation under load. In the current paper, a discussion o f computer modeling and model verification for canister structures is presented. Two different approaches for performing computer simulation of the response of canister structures are discussed. One approach co nsists of a brute force detailed finite element model in which a class ical finite element technique is employed to model the structure in gr eat detail. The second approach employs a reduced-order, equivalent co ntinuum model to represent the canister structure. The continuum model is based on a special purpose methodology which allows representation of the global behavior of large canister structures with an efficient and economical model. Canister modeling results for both modeling app roaches are presented in this paper and compared to experimental data from actual canister tests. Finally, the utility of numerical simulati ons in identifying an effective technique for canister frame stiffenin g is discussed.