The Study Of Thermodynamic Behavior Of AHSS Plate

Advanced High Strength Steel(AHSS)refers to steel that is reinforced by phase change to steel.These steel grades usually contain bainite,martensite or retained austenite.AHSS is generally include two-phase steel(DP),phase change induced plastic steel(TRIP),composite steel(CP),martensitic steel(M),twin induced plastic steel(TWIP)and thermoformed steel(HF),etc.In recent years,the application of AHSS in the automotive industry is also more and more widely.In this paper,combining various external conditions and the self-property of the material,the AHSS plate has been considered as the research object,and the thermodynamic behavior of AHSS is studied.Firstly,based on the Von Karman equation,classical thin plate theory,thermoelastic theory,Hamilton principle and modified nonlinear Hertzian contact theory,the nonlinear control equation of rectangular AHSS plate under impact loading is obtained.Then,the finite difference method,Newmark method,Galerkin method,Newton-Cotes numerical integration method and iterative method have applied to solve the whole problem.Finally,the influence of geometric size,mechanical load,temperature,moisture and viscoelastic effect on the nonlinear dynamic response of AHSS plate is discussed and analyzed by numerical examples.Based on the above methods,the thermoelastic behavior for a rectangular AHSS plate under the impact load,the thermomechanical behavior of a rectangular AHSS plate with HSLA stiffeners under the impact load,the thermoviscoelastic dynamic response for a rectangular AHSS plate under laser processing and the investigation on a rotating AHSS circular plate under a coupled hygrothermal field have been studied.The research of this thesis enriches and develops new materials,nonlinear dynamics and thermodynamic coupling theory.It will also provide some theoretical basis for further study of the mechanical behavior,optimization design and experimental study of AHSS plate structure,which has certain engineering practice significance.