Study On The Coupling Effect Between Solitary Waves And Fiber Reinforced Composite Plate With Internal Defects

Solitary waves were initially a special form of motion in ocean waves,but later researchers discovered that highly nonlinear solitary waves can be generated in one-dimensional particle chains composed of granular media.The characteristic information carried by solitary waves can be used for non-destructive testing and evaluation of the mechanical properties of engineering structures in the field of engineering,and has a very broad application occasions.Based on the interaction between solitary waves and composite plates with different damage types,a complete set of coupled differential equations for one-dimensional particle chain and composite plate with different damage types is established.Analyze the characteristic information of reflected solitary waves and the variation patterns between different types and degrees of damage,in order to achieve the goal of using highly nonlinear solitary waves for non-destructive testing and structural health diagnosis of fiber reinforced composite plate containing internal defects.The main research contents of this article:(1)Study on the motion characteristics of one-dimensional particle chain and establish differential equations for their coupling with composite laminates.According to Hertz contact law,the relationship between contact force F and compression δ when two elastic particles come into contact with each other is derived,and the differential equations of motion for one-dimensional homogeneous particle chain and one-dimensional composite particle chain are established.The force of the end particle on the composite laminated plate is regarded as a concentrated force,and the displacement of the plate from the initial position after the plate is subjected to the concentrated force is obtained.Finally,the differential equations of the coupling between the particle chain and the composite plate are obtained.(2)Study on the coupling effect between solitary waves and composite plate with interior delamination damage.Based on the continuum damage model of micromechanics theory,the relationship between the stiffness coefficients of laminated plate with interior delamination damage is determined by using the classical invariant theory,and the coupling differential equations of one-dimensional particle chain and composite laminated plate with interior delamination damage are obtained.Using the fourth order Runge-Kutta method to solve the differential equations,analyze the effects of thickness,average diameter of cracks,and density of cracks on reflected waves in glass/epoxy and graphite/epoxy composite material plate.And analyze the variation law of reflected waves when using one-dimensional homogeneous chain(γ=1)and one-dimensional composite chain(γ=0.125)to detect interior delamination damage in composite plate.(3)Study on the coupling effect between solitary waves and composite plate with interfacial slip damage.The second-order tensor is used as the internal state variable to represent the basic damage entity,and the relationship between stress-strain and damage is derived.The specific expression of the engineering elastic modulus with the change of damage when the interface slip damage occurs due to matrix cracking is obtained,and the coupling differential equations of one-dimensional particle chain and interfacial slip damage composite plate are constructed.The effects of crack opening displacement and fiber volume fraction on solitary waves in one-dimensional homogeneous chain and one-dimensional composite chain are studied.Finally,the propagation characteristics of solitary waves in one-dimensional composite particle chains placed vertically are analyzed.