Analysis On The Similarity Law Of Dynamic Response For Stiffened Panels Under Blast Loading

It is hard to satisfy the completely similarity law for the dynamic response of structures when they are subjected to dynamic load,which might be caused by the strain-rate sensitivity,fracture and heat effect of the structural materials;besides,owing to manufacturing technical restrictions,the geometry of scaled models cannot comply with the overall geometric scaling factor from that of the prototype,therefore a corresponding geometry distorted model need to be introduced in such cases.In order to obtain a reliable predictive result,a reasonable similarity law is demanded to instruct operating thescaled model experiments.This paper first explored the influence factors that included in the dynamic response of structures by virtue of the similarity theory anddimensional analytical method,and then discussed the similar distortion rules and distortion similarity law for stiffened panels under blast loading.The research work of this paper aims to provide guidance for conducting dynamic load tests and it could be divided into several sections,which are as below:Firstly,the influence of thestrain-rate effect that brings to the similarity law was explored by virtue of dimensional analytical method;then a correction equation was put forward by analyzing the relationship between the impulse per unit area and the strain-rate effect,which took the impulse per unit area as the correction object and could help satisfying the similar relationship of dynamic response between scaled models and the prototype.Secondly,a calculation formula about the impulse per unit area was built based on the relevant references and the value of the impulse per unit area could be obtained by substituting the corresponding values of the mass of TNT and the stand-off distance into it.This formula provides an easy way to adjust the mass of TNT according to the corrected result of the impulse per unit area.Thirdly,a study about the similarity law for the dynamic response between distorted scaled models and the prototype was carried out.The two common correction methods,the FEM predictive coefficient method and the exponent correction method,were compared with each other through the Calladine model example.According to the comparison results,the latter one was chosen as the main method to deal with this kind of issues.Then,a rapid solution to the value of exponent n was proposed,which made the exponent correction method could be more smoothly used in practical engineering.Finally,the similar relationship of dynamic response between a double geometric parameters distorted model(the thickness of the panel and the type of stiffeners were distorted)and the prototype was explored in further.In this section,an improved correction method was proposed based on the exponent correction method and it could achieve a good predictiveresult for the dynamic response of the stiffened panels under blast or internal blast loading.