Results – Stresses in Frame From the Aluminum Association, Specifications for Aluminum Structures (FOS > 1.5): Maximum fiber stress for 6061-T6 unwelded = 131 MPa Maximum fiber stress for 6061-T6 welded = 75.8 MPa Verification of High stress: Stress classification line through weld gives membrane stress 88.5 MPa and membrane + bending 175.6 MPa which are well below the allowables for secondary stresses of 1.5 Sm for membrane and 3 Sm for membrane + bending from ASME VIII Div.