激光熔融316L不锈钢方管T形相贯节点的轴压性能OA

To investigate the mechanical properties of the integrally formed square stainless steel tubular T-joints fabricated by selective laser melting(SLM).12 square tubular T-joints using 316L stainless steel power with varying width ratios,width-to-thickness ratios,and thickness ratios were printed.The main geometric parameters of the T-joints were obtained via three-dimensional laser scanning,and the forming accuracy and surface features were analyzed.Axial compression tests were then conducted to obtain the failure modes,load-deformation curves and key performance parameters of the T-joints.The differences between the bearing capacity test results and the bearing capacity predictions given by relevant domestic and international standards were evaluated.The results show that for specimens with the same side length of the chord tubular section,the bearing capacity significantly increased as the width ratio gone from 0.6 to 1.0,reaching nearly 10 times the original value and exhibiting various failure modes.The factors influencing the bearing capacity of the joints were,in order of importance,the width ratio,which played a controlling roll,the width-to-thickness ratio,which had a certain influence,and the thickness ratio,which had a relatively small influence.The failure modes of the T-joints included plastic failure of the chord flange,buckling failure of the chord web and combined failure modes,with local buckling of the brace involved in some specimens.For several T-joints,the measured bearing capacities were lower than the predictions of the Chinese standard GB 50017-2017;thus,design based on this standard may be non-conservative.The bearing capacity predictions of the international standard CIDECT and the European standard EN 1993-1-8:2020 generally provided the lower-bound values relative to the test values,indicating that design based on these standards is safe.