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Lumped damage mechanics or LDM is a branch of structural mechanics that is concerned with the analysis of frame structures. It is based on continuum damage mechanics and fracture mechanics. It combines the ideas of these theories with the concept of plastic hinge〔Marante, M.E., Flórez-López, J., “Three-Dimensional Analysis Of Reinforced Concrete Frames Based On Lumped Damage Mechanics” International Journal of Solids and Structures Vol 40, No 19, 5109-5123, 2003.〕 LDM can be defined as the fracture mechanics of complex structural systems. In the models of LDM, cracking or local buckling as well as plasticity are lumped at the inelastic hinges. As in continuum damage mechanics, LDM uses state variables to represent the effects of damage on the remaining stiffness and strength of the frame structure. In reinforced concrete structures, the damage state variable quantifies the crack density in the plastic hinge zone;〔 in unreinforced concrete components and steel beams, it is a dimensionless measure of the crack surface;〔Amorim, D.L.N.D.F., Proença, S.P.B.,Flórez-López, J. “Simplified modeling of cracking in concrete: Application in tunnel linings” Engineering Structures, 70, pp. 23-25 (2014)〕 in tubular steel elements, the damage variable measures the degree of local buckling〔Marante, M.E., Picón, R., Guerrero, N. And Flórez-López, J. “Local buckling in tridimensional frames: experimentation and simplified analysis” 9(2012) 691 – 712 Latin-American Journal of Solids and Structures.〕 The LDM evolution laws can be derived from continuum damage mechanics〔〔Santoro M, Kunnath S. Damage-based RC beam element for nonlinear structural analysis. Eng. Struct. 2013; 49:733–742.〕 or fracture mechanics.〔〔 In the latter case, concepts such as the energy release rate or the stress intensity factor of a plastic hinge are introduced. LDM allows for the numerical simulation of the collapse of complex structures with a fraction of the computational cost and human effort of its continuum mechanics counterparts. LDM is also a regularization procedure that eliminates the mesh-dependence phenomenon that is observed in structural analysis with local damage models 〔Toi, Y., Hasegawa, K.H.,. "Element-size independent, elasto-plastic damage analysis of framed structures using the adaptively shifted integration technique" Comput. Struct. 2011; 89, 2162-2168〕 ==References== * * * * 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lumped damage mechanics」の詳細全文を読む スポンサード リンク
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