Study On Damaga Of Composite Structures Subjected To Combined Action Of Shock Wave And Fragments Based On Peridynamics

With the wide application of all kinds of advanced anti-ship weapons in modern marine war,the threat of ships is becoming more and more serious.Depending on its powerful maneuverability and precision guidance ability,anti-ship missile produces air blast shock wave and high-speed fragment clusters to form a joint action damage to the main body of the ship,which is the main threat to large surface ships.The protective bulkhead structure is the last defense barrier of the ship and the guarantee of the vitality of the ship.However,the existing steel bulkhead is not enough to resist the damage caused by the combined action of shock wave and fragments.Thickening the bulkhead to improve the protective ability will increase the weight and weaken the maneuverability.Therefore,the lightweight,good mechanical properties and designable fiber reinforced composites have gradually become a new choice of protective structural materials.Therefore,it is of great engineering significance to carry out the damage research of composite structures under the combined action of shock wave and fragment clusters.Although the composite material has excellent performance,its damage mode is complex,and the traditional method has singularity for the problem of structural discontinuity.Therefore,a new meshless method,peridynamics(PD),is adopted in this paper.Its theoretical equation uses integral form instead of differential partial derivative term,which avoids the singularity of structural discontinuity.The damage definition in the constitutive model can well simulate the damage of composite structures under the combined action of shock wave and fragment clusters.In this paper,according to the load characteristics of composite structure,the load is decomposed into fragment clusters load and shock wave fragment clusters combined action.Firstly,the history and development of peridynamics are reviewed,and the research status of structural damage under fragment load and shock wave load in the field of ship protection is briefly introduced.Secondly,the theory of peridynamics is introduced in detail,and its motion equation,damage definition and other parameters are deduced.Then,the bond-based peridynamics method is introduced,and the bond-based Pd complex model is constructed.Then,the damage mode and damage process of fiber reinforced composite laminates and stiffened plates under the action of high-speed fragments are analyzed by using the above theoretical method,and the influence of the number of fragments and other key factors on the penetration ability of fragments is considered.Finally,the numerical simulation is carried out.The damage mode and overall deformation of composite plate and stiffened plate under combined action of shock wave and fragment clusters are analyzed,and the influence law of load order on damage ability of combined action is considered.From the above analysis and a series of conclusions,the effectiveness of PD method for structural damage analysis is verified,and the conclusion of engineering significance is given for the application of composite materials in ships.