ドリフトピン接合によるモーメント抵抗接合部を対象とした複合応力検定式におけるべき数の決定方法に関する研究

Abstract

The purpose of this paper is to appropriately judge the decision method for exponents of verification formula for combined stress in the safety side. The decision method allows it to determine by showing the evaluation standard that derived by mechanical model. Relation between each stress and aspect pressure is given by Eq.(2), when bending moment, shear force, and axial force is given at the bending moment resisting joint by drift-pin joint. PM = M⁄j …(2a) PQ = Q⁄2 …(2b) PN = N⁄2 …(2c) Since the directions of bending moment and aspect pressure by axial force are the same direction, it becomes Eq.(3a), and Eq.(6) may be obtained by substituting Eq.(2a) and Eq.(2c) for Eq.(3a) and Eq.(5). P0 = PM + PN …(3a) Py0 = PM + PN …(5) PM⁄Py0 + PN⁄Py0 = M⁄M0 + N⁄N0 = 1 …(6) Therefore, the exponent shall be m=1 in verification formula for combined stress. On the ather hand, due to aspect pressure acts on orthogonality force is given in Eq.(8) for the combined stress by bending moment and shear force. Sine the strength of the drift-pin at any angle is represented by Hankinson's formula (Eq.(7)), the condition which combined stress becomes a yield strength or ultimate strength is when it is to be Eq.(9). Therefore, the verification formula for combined stress by bending moment and shear force is effected by strength at any angle shown by Hankinson's formula. PMQ = √(PM2 + PQ2) …(8) Pyθ = (Py0·Py90)⁄(Py0·sinnθ + Py90·cosnθ) Generally n = 2 …(7) PMQ = Pyθ tanθ = PQ⁄PM } …(9) Moreover, combined stress by bending moment and shear force has big effect on secondary moment of disposition of the drift-pin, and depends on the layouts of the drift-pin, the exponent m=2 may become hazard side. However, by using relation between secondary moment of disposition obtained in a numerical analysis and the exponent shown in Eq.(18), It becomes evaluable in the safety side. m = 0.12×((Ix·P90)⁄(Iy·P0))2 - 0.47×((Ix·P90)⁄(Iy·P0)) + 2.00 …(18) (M⁄M0)m + (Q⁄Q0)m ≤ 1 …(20) For the combined stress of bending moment-axial force-shear force, it becomes combination as the above. Since the directions of bending moment and aspect pressure by axial force are the same direction, the exponent of verification formula for combined stress is to be m=1. Since aspect pressure by shear force acts on orthogonal to resultant force of bending moment and axial force, the exponent of verification formula for combined stress to be m=2. Eq.(21) is shown in verification formula for combined stress using these numbers. {(M⁄M0) + (N⁄N0)}m + (Q⁄Q0)m ≤ 1 …(21)