Plate and shell structures

Modeling Structural Complexity

Steel plate under blast load
Complex steel plate structures commonly found in civil and mechanical construction can be modeled in great detail with MARS. Contact conditions between all entities in the model ensure that plates do not penetrate each other. Rivet, bolt, or weld elements are used to hold plates and braces together. Numerical simulation (left) and the test results (right) of a blast resistant door subjected to close-in charge.
Numerical simulation (left) and the test results (right) of a blast resistant door subjected to close-in charge.
Figure 1. Detail of a MARS FE model of a steel-plate cell structure typical of many engineering projects.
Laceration and 2D fragmentation
The MARS laceration algorithm is essentially a two-dimensional version of the solid fragmentation algorithm presented earlier. Cracks can develop between clusters of shell elements depending on specified local failure criteria. Cracks can propagate or coalesce to form tears. All material is fully accounted for as all mass is maintained and balanced.
Shown above are the results of a MARS simulation of the break up of plate bolted to a fixed reactive structure subjected to a large blast load.
Reinforced concrete wall responces to blast
The structural response of reinforced concrete structures to blast loads and fragment impacts is a problem of great interest to the defense community. MARS features unique methods to treat rebar-concrete interaction. Rebars are modeled using strings of beam finite elements capable of bending and torque resistance. Rebars are independently generated and embedded in the concrete. Non-linear relationships govern the bond slip behavior to simulate rebar pull-out.
A MARS simulation computes the response when a blast explodes near a reinforced concrete. The concrete breaks up under the extreme loading conditions and the reinforcing rebars (shown in red) become exposed.
Vehicle responces to blast
Conversion filters in MARS translate models developed for other codes. In the example below, the model of a Ford Taurus, developed at GWU for crash simulations, was employed to simulate the effect of surface charges applied on the vehicle.
Shown above is the model of a Ford Taurus (developed at GWU) subjected to external charge loads.