Study On Dynamic Fracture Toughness Of Fiber Reinforced Composites By SHTB Experimental Numerical Method

With the development of Materials science,Composites have been widely used in the related industries of national economy in recent years due to their superior mechanical properties.Through the analysis of large number engineering accidents,many causes of damage are from the fracture behavior of materials.Fracture behavior is very dangerous and imperceptible,The reason is that it's easy to form internal cracks in the process of production and practical application.When materials are subjected to the load,the existence of cracks make the members to crack at a stress value much less than the strength criterion.Many fracture accidents occurred in the safe load range,so the internal cracks of engineering members have great hidden danger of safety.Therefore,it's very important and far-reaching to research the dynamic fracture of the crack in composite materials,which has become a subject of attention and research by more and more researchers.This paper use the compact tensile specimen model which is made of glass fiber reinforced composites.And using Hopkinson's rod experiment technique to study the mechanical behavior of the sample.At the same time,numerical simulation software is used to verify the experimental process and explore deeper influence of sample-related parameters on the dynamic fracture behavior of composite materials.The main contents of this paper include:Select the compact tensile specimens which were prepared by glass fiber reinforced composite materials,use mechanical testing machine to get the determination basic mechanical properties of the material and the curve of relevant parameters.Hopkinson rod dynamic fracture experiment was carried out by using two kinds of laying materials.The J criterion was used to characterize the dynamic fracture toughness of the material,and the orthogonal experimental data were compared with the experimental data of 45 degree laying laminates.At the same time,numerical simulation soft ware was used to simulate the dynamic fracture experiment,and obtain the dynamic fracture toughness simulation values of two samples.The accuracy and feasibility of numerical simulation were verified.And we can get the stress distribution of specimen.The numerical simulation software was used to study the effect of material parameters variation in the stress distribution and dynamic fracture related parameters.These parameters mainly include changes in the laying angle of the ply,the specimen thickness changes,the crack length changes.When the parameters of the specimen are changed,by using the principle of control variables,research the influence of several relevant mechanical parameters such as the stress change and distribution of the specimen,the initiation time of the specimen,the maximum stress value and the dynamic fracture toughness value,and get the curve and value of these related variables.Then the law of the relevant parameters of composite laminates during the dynamic fracture experiment was obtained,and lay the foundation for the follow-up research work and provide the reference.