Research On Design Optimization Of Blast Resistance Of Pyramidal Lattice And BRAS Sandwich Panels

Today,local wars such as terrorist attacks frequently occur.In military operations such as anti-terrorism,military vehicles often face attacks from explosive devices such as mines,which seriously threaten the safety of the occupants and materials inside the military vehicles.In order to improve the armor protection performance of military vehicles,this paper launched a design optimization study on the protection structure of military vehicles such as floor and body.As a new type of multi-functional structure,the sandwich structure shows excellent performance in terms of anti-dynamic impact and explosion energy absorption.This structure can be widely used in military vehicles,aerospace and ship protection.Lattice core sandwich structures,corrugated sandwich structures,honeycomb structures,etc.are common sandwich structures.The complexity,size and arrangement of the core layer of the sandwich structure provide researchers with a shortcut to realize the diversification of the structural design,making it possible to improve the blast resistance by changing the specific form of the core of the sandwich structure.In this thesis,a pyramid lattice structure sandwich panel with a variable cross-section web core and a corrugated sandwich structure called BRAS(Blast Resistant Adaptive Sandwich)are focused.Numerical analysis is used and LS-DYNNA? is selected as solver for simulation.A finite element model was established in Hyperworks? 14.0 and the reliability verification of the finite element modeling method was performed.The anti-blast performance of several structures and the effect of the structural parameters on blast resistance were analyzed.Based on the parametric analysis,the structural parameters are used as design variables,and the blast resistance is used as the optimization objective.The integrated process such as parametric modeling is used to obtain the required design of experiment(Do E).Multi-objective optimization and robust design are conducted,and finally we obtained a set of optimal structural design(Pareto fronts)under specific loading conditions,which provides options for the structural design of military vehicle protective armor.The results show that the energy absorption capacity of the variable cross-section web pyramidal lattice sandwich panel is better than that of the constant cross-section web pyramidal lattice sandwich panel under certain load conditions,while the back face-sheet deformation is increased.Similarly,the energy absorption capacity of the BRAS structure is significantly stronger than that of the USDH(Unidirectionally Stiffened Double Hull)and TC(Triangular Corrugated)structures,but the back face-sheet deformation of BRAS structure will also increase.For the variable cross-section web pyramid lattice sandwich panel and BRAS structure,their energy absorption characteristics and resistance to deformation are always difficult to improve in synergy,and the blast resistance changes caused by load conditions are also very obvious.Through the multi-objective optimization design on the blast resistance of the two structures under specific working conditions,the optimal design superior to the initial design is obtained.