Theoretical And Experimental Study On Mechanical Properties Of Weld Zone Of Aluminum Alloy Welded Joints

Aluminum alloy welded joint is a conventional connecting structure widely used in engineering,which may be subjected to all kinds of deformation,such as tension,compression,shear and torsion during their service.More often,a combination of different deformation loading,such as tensile-shear loading,is simultaneously applied to a single welded joint.In this paper,the stress-strain constitutive relations of weld zone of aluminum alloy welded joints under uniaxial tensile,shear and tensile-shear loading were studied.The width of weld zone of aluminum alloy welded joints is narrow and the mechanical properties of weld zone has a great gradient,As a result,it is difficult to determine the mechanical properties of the weld zone by cutting it to test on mini-specimens.On the other hand,the stress-strain constitutive relation of material in the weld zone can’t be directly determined by the welded joints test.Therefore,in this paper,both the experimental and numerical analysis were conducted to study the mechanical properties of A2219 aluminum alloy welded joints of welded joint under tensile loading,shear loading and tensile-shear loading.Firstly,the strain history of weld zone of friction stir welding joints of A2219 aluminum alloy under tensile,shear and tensile-shear loading were measured by opticalmeasurement system.The nominal stress-strain curves of each optical measurement point in the weld zone were obtained.Secondly,the stress-strain constitutive relation of materials under uniaxial tensile,shear loading and tensile-shear loading were deduced respectively,which is expressed in Ramberg-Osgood equation forms.Finally,by fitting the nominal stress-strain curves obtained by test,the starting mechanical properties parameters in equation were obtained.By the help of finite element software ABAQUS,the mechanical property parameters of materials in the weld zone of the three specimens were determined by the inverse calculation method.The mechanical properties parameters obtained of weld zone of tensile specimens,shear specimens and tensile-shear specimens of aluminum alloy welded joints were compared.The results showed that the mechanical properties parameters of the three types of specimen in the same geometric location of weld zone were basically the same.Therefore,tensile test on the aluminum alloy welded joint can be used to determine the mechanical properties of the weld zone,which can be applied to evaluate mechanical behavior of welded joints subjected to shear or tensile-shear loading.