The Modal analysis gives two orthogonal bending modes with identical natural frequency.<\/span><\/p>\n The used response spectrum is constant for 1Hz-1000Hz with acceleration of 1000mm\/s².<\/span><\/p>\n The response spectrum is applied in both horizontal directions X&Y.<\/span><\/p>\n For Modal Combination CQC is used with 2% damping.<\/span><\/p>\n The orthogonal combination technique is SRSS (default in ANSYS).<\/span><\/p>\n The RSA results in a normal stress of 1.2759MPa at the fixed end of the beam, constant around the circumference of the circular cross section.<\/span><\/p>\n The bending moments at the fixed end of the beam are Mx=1000Nmm, My=1000Nmm.<\/span><\/p>\n In total Mtotal=SQRT(1000²+1000²)=1414.2Nmm.<\/span><\/p>\n Taking this moment Mtotal for stress calculation via Mtotal\/W gives a normal stress of 1.8006MPa.<\/span><\/p>\n So there is exactly a factor of sqrt(2) between the directly received stress results and the stress result calculated via the bending moment.<\/span><\/p>\n 1.8006\/1.2759=sqrt(2)<\/span><\/p>\n This raises the question: What is the correct approach for verification of the cross-section? Should I use the stresses calculated directly in the RSA, or should I use the bending moment? Where is the mistake \/ misinterpretation?<\/p>\n Thanks for help.<\/p>\n","protected":false},"template":"","class_list":["post-462332","topic","type-topic","status-publish","hentry","topic-tag-responsespectrumanalysis-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t<\/span><\/p>\n
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