Failure Properties And Modeling Analysis Of Aeronautic Rivet Connection

Under the transport aircraft crash test,connection failure is one of the main forms of structural failure.In the crash test,the connection structure is susceptible to failure due to impact forces of different speeds and different angles.It is important to study the failure properties of the riveted structure under different loading speeds and loading angles for the study of crashworthiness.As the main failure structure.connection model will greatly affect the simulation accuracy of the overall model.In this paper,the rivets that are easy to fail at the joints during the crash test are investigated.Failure properties of the rivets was analyzed through test,and the finite element modeling method was studied.In order to analyze failure properties of the countersunk and flat head rivets,dynamic tests were performed at different loading speeds and angles.The failure mode is mainly affected by the loading angle,including the rivet head pull-out and the shank shear.The loading speed have no effects on the composite loading test of the countersunk head rivet and the flat head rivet at all angles.There is a linear relationship between the failure load and the loading speed for pure tension and pure shear of the countersunk head rivet.The failure surface of two rivets is established.The maximum tensile load and the maximum shear load of the countersunk head rivets at different loading speeds need to be changed.But the strain rate don't affect the failure surface of the flat head rivet.Considering the influence of the base material,composite loading tests of riveted structures with different connection thicknesses and loading angles were carried out.The loading angle has a greatly influence on the failure mode,and as the thickness of the connecting member decreases,the rivet is more prone to pull-out failure.However,when the failure is the shank sheared,the failure load and failure displacement are less affected by the thickness of the connector.The failure surface of the riveted structure expands slightly as the thickness of the connection increases.Establishing the riveted structure models of different element types and material models to model the riveting test of composite loading,and found that the 8 hexahedral clusters has the best results for failure load simulation,but the failure displacement error is large.The SPR2 model failure load simulation error increases,but still less than 10%,the failure displacement error is small,so the overall simulation result is better.After that,the single lap test was used to verify the model.Then design a double rivets test that can cause the connection plate to fail,and study the modeling method of the connection plate failure.8 Hexahedral cluster model and SPR2 constraint model cannot effectively simulate the failure of the connecting plate.A solid model of "I" with rivet holes must be established to simulate the failure of the connecting plate.