Experimental Investigation And Bearing Capacity Calculation Method Of 6082-T6 Aluminum Alloy Beams With Box-section And H-section

Compared with the traditional 6061-T6 aluminum alloy,6082-T6 aluminum alloy is better in strength,corrosion resistance and weldability.The application prospect of 6082-T6 in civil engineering is good.Experimental and numerical studies of three-point bending beams of box-section and H-section extruded from aluminum alloy of 6082-T6 were performed in this paper.The direct strength method was introduced into the calculation of bearing capacity of aluminum alloy beams.The calculation method of bending strength considering the material nonlinear characteristics and initial geometric imperfection,was put forward for 6082-T6 aluminum alloy bending members with box-section.As well,design approach account for the lateral-torsional buckling and local-overall interaction buckling was proposed in this research.The specific work of this paper is as follows:(1)The mechanical parameters of domestic aluminium alloy 6082-T6 are obtained from tensile tests of 32 coupons and other 143 stress-strain curves,including elastic modulus E0,yield strength f0.2,tensile strength fu,percentage total extension at fracture At,and Poisson's ratio v.Comparison of experimental stress-strain curves of 6082-T6 aluminium alloy and the Ramberg-Osgood constitutive model demonstrates that the Ramberg-Osood model can accurately represent the stress-strain curve of domestic aluminium alloy 6082-T6.The parameter n describing strain hardening can be calculated by Steinhardt Suggestion,taking as n = f0.2/10.(2)25 three-point bending tests of 6082-T6 aluminum alloy was carried out,including 19 box-section beams(Square Hollow Section and Rectangle Hollow Section)and 6 H-section beams.There were two failure modes in box-section beams: material yielding and local buckling.For SHS beams,if ?y?60,both material yielding and local buckling happened;if ?y>60,just material yielding happened.RHS beams was similar with SHS beams except ?y=80 was the dividing line.H-section beams failed by torsional-flexural buckling.(3)An accurate finite element model was established for all three-point bending aluminum alloy beams using the finite element software ABAQUS.The simulation results were compared with the experimental results.It showed that the finite element model can predict the loading and destruction process,deformation and carrying capacity well.The validated model was used to build 936 numerical beams,which considered the effects of some factors,including grid size,initial geometric imperfection,cross-section type and size,minor axis slenderness ratio.(4)Based on direct strength method,the calculation method of bending strength,was put forward for 6082-T6 aluminum alloy bending members with box-section.Compared with the experimental data,finite element results and national design specifications,it showed that the calculation method proposed in this paper can be more accurate and convenient in predicting the bearing capacity of 6082-T6 aluminum alloy three-point bending beams of box-section.(5)Reference to European and Chinese codes,two capacity methods with high accuracy named P-R-fit and P-D-pro were proposed for H-section cross-section based on Perry-Roberson formula and the direct strength method.Both of them can predict the failure modes and related bearing capacity well.