Fatigue Reliability Study On The Clinched Joint Of Aluminum Alloy-foam Metal "Sandwich" Structure

The usage of new lightweight sheet,like aluminum alloy,magnesium alloy and polymer material,is wilder than before,which takes a great challenge to existing plate connection technologies.As a mechanical connection technology,clinch is convenient and has no special requirements for the materials,which makes it to be a great potential plate connection technology.Clinch still has some weakness,for example,the static strength of clinched joint isn't high enough.In this article,a method of improving the mechanical properties of clinched joint by adding foam metal interlayer is presented.The single lap and cross lap clinched joints of Al5052 aluminum alloy with different foam metal interlayer were prepared respectively,then tensile-shear strength and peel strength of that were tested.The test results show that adding foam metal interlayer can effectively improve the tensile-shear strength of clinched joints;The fracture and microstructures of the joints failured in tensile-shear and peel test were annlyzed by scanning electron microscope;On the baisis of static test,the fatigue tests of Al5052 aluminum alloy clinched joints with no interlayer and foam copper and foam iron-nickel interlayer were made to study the influence of foam metal on the fatigue life of the clinched joint,the test results show: adding foam metal interlayer can greatly improve the fatigue life of clinched joint;Fracture analysis results show that after adding foam metal interlayer,the neck of clinched joint is more prone to generate fatigue crack source.So far,there is no research about adding foam metal interlayer to improve the mechanical properties of the clinched joint,in terms of safety and reliability,the reliability analysis about the fatigue life of the clinched joints of Al5052 aluminum with foam copper and foam iron-nickel interlayer were also analyzed in this paper,and the P-F-N curves under different survival rates were fitted.