Research On The Protective Performance Of A Vehicle's High-strength Bolt Structure

In the military warfare,army used vehicles often use high-strength bolts to connect,but the vehicles are usually to cause bolts to fall off in the mine explosion conditions.After the bolts fail,it results in a significant impact on the vehicle body structure and vehicle defense capabilities.Therefore,the research of high-strength bolt structure protection performance to improve vehicle protection has great and far-reaching significance.Taking a military transport vehicle as the research object,this paper studies the influence of bolt on the protective performance of military vehicles and how to select the high-strength military vehicles based on the bolt design criteria,bolt modeling and simulation method,explosion theory,vehicle explosion simulation and vehicle explosion test Strength bolts and optimize the protection of high-strength bolt structure.The main research process is as follows:First of all,based on the calculation method of the prestressing force of high strength bolts and the design standards,the finite element modeling method of bolt and the method of applying bolt pretension are studied.The conclusion is drawn that in the protective vehicle model,the analog of solid element bolt and the using prestress instead of bolt preload are more appropriate.Then,taking the constrained square target as an example,the advantages and disadvantages of the commonly used explosion simulation algorithms ALE and SPH are compared,it’s concluded that ALE is the most suitable simulation algorithm for the vehicle explosion.For the important protective materials of whole vehicle such as bullet-proof steel,the SHTB test was performed to obtain the J-C constitutive model of the material,and other materials using the elastoplastic model.In addition,through the finite element modeling and calculation of the complete vehicle,the calculated dummy response,acceleration response and body failure morphology are compared with the vehicle explosion test,and it is concluded that the failure of the bolt has a significant impact on the vehicle’s protective performance.A detailed analysis of the sub-frame bolt failure timing and failure of the mechanical properties is carried out,and the sub-frame bolts are reselected.Finally,based on the multi-objective optimization algorithm,the protective components of high strength bolts are optimized and the optimized protective structure is simulated in explosion case.Compared with the experimental results,the structure of the bolted protective components is verified to improve the protection of the vehicle performance.