Roof crush laboratory tests (simulating rollover car behavior) usually take 10 to 30 seconds to crush the car to the required maximum displacement of the crushing panel. Therefore, it is clearly an almost static or quasi-static problem. It is apparent that a natural way to obtain a solution is to use an implicit/static approach to solve roof crush problems.
However, in practice, explicit codes are used with much factor-adjusting. The problem is very difficult to solve implicitly due to buckling, self-contact and material and geometric nonlinearities. Absolutely essential here are robust finite elements and clean solution techniques. To demonstrate the capability of ADINA in handling this class of problems, we present a roof crush analysis by implicit solution with ADINA.
The above animation depicts the result of the analysis. In the figure that follows, comparisons are made between implicit and explicit solutions obtained by Ford engineers. In the explicit solution case, different results were obtained for different speeds and/or mass data. With ADINA, the implicit solution was obtained on a 1.7 GHz dual processor PC in a single run of less than 11 hours, whereas four runs are needed in the explicit solution case.
