Bonding Influence On Static Strength Of Bolted Joint Of Carbon Laminate And Aluminum Alloy Plate

The static strength tensile tests of carbon fiber composites laminate and aluminum alloy plate joints are carried out,in which four cases are considered including single-bolted bonded joints,single-bolted joints,double-bolted bonded reaming joints and double-bolted reaming joints.Finite element models of the four cases are established.The three-dimensional Hashin and Puck criterions are embedded in the analysis models by subroutine programming.The debonding mechanism of the adhesive layer between the laminate and aluminum plate is studied.The damage evolution process of the carbon fiber laminate is analyzed.The numerical models are revised based on test data.For the corrected single-bolted bonded joint model,the relative error of the initial peak load between the finite element model and the test value is 2.9%,and the error of the second peak load is 14.8%.It is showed that high-strength adhesive layer improves the joint strength and expands safety margin of the single-bolted bonded joint.The higher the adhesive strength,the higher the peak load.When the debonding occurs between the laminate and aluminum plate,the second peak load is lower than the initial one.The second peak load is consistent with the peak load of the non-adhesive single-bolted joint.The joint stiffness and stability of the single-bolted bonded joint with adhesive in the bolt hole are better than that of the joint without adhesive in the bolt hole.For the corrected double-bolted bonded reaming joint models,the relative error of the peak loads between the finite element models and the test values are about 1.70%-28.3%.It shows that high-strength adhesive layer improves the strength of double-bolted bonded reaming joints.The higher the adhesive strength,the higher the peak load.The load of bolt D2 is higher than that of the D1.The increase of D2 diameter improves the ultimate strength of double-bolted bonded reaming joints.After the peak load is met,the bolt hole of the carbon fiber laminate is compressed in a stable buckling-collapsing process,and the load value decreases gradually.The clamped end and loading end interchange of the joint specimens has little influence on the test data.The debonding mechanism of the adhesive layer between the laminate and aluminum alloy plate and the failure evolution process of the carbon fiber laminate under displacement loading are simulated well by the finite element models established in this thesis.