In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relat...In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relations, which are given by the increment theory of elastoplasticity. Thus, the finite element equation with the solution of displacement is derived. The assemblage elastoplastic stiffness matrix can be obtained by adding something to the elastic matrix, hence it will shorten the computing time. The determination of every loading increment follows the von Mises yield criteria. The iterative method is used in computation. It omits the redecomposition of the assemblage stiffness matrix and it will step further to shorten the computing time. Illustrations are given to the high-order element application departure from proportional loading, the computation of unloading fitting to the curve and the problem of load estimation.展开更多
The cyclic stress-strain responses (CSSR), Neuber's rule (NR) and cyclic strain-life relation (CSLR) are treated as probabilistic curves in local stress and strain method of low cycle fatigue analysis. The randomn...The cyclic stress-strain responses (CSSR), Neuber's rule (NR) and cyclic strain-life relation (CSLR) are treated as probabilistic curves in local stress and strain method of low cycle fatigue analysis. The randomness of loading and the theory of fatigue damage accumulation (TOFDA) are considered. The probabilistic analysis of local stress, local strain and fatigue life are constructed based on the first-order Taylor's series expansions. Through this method proposed fatigue reliability analysis can be accomplished.展开更多
The whole depth measuring plan and its implementation method of surrounding rock mass pressure on the wall′s of a shafts are described, which is in Suncun Coal Mine with a depth of 1 000 m.Then with the combination o...The whole depth measuring plan and its implementation method of surrounding rock mass pressure on the wall′s of a shafts are described, which is in Suncun Coal Mine with a depth of 1 000 m.Then with the combination of data processing, it is discussed the effects of such factors on the distribution law of shaft surrounding rock pressures as rock quality,burying depth, end effect due to excavating, rock stratum dip, shaft wall structure form and regression formulae relating to the shafts surrounding rock pressures as well as to several other factors.And finally, the measured results were verified according to the comparison between analyses of stress strain of side walls and side wall strain measurements.展开更多
文摘In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relations, which are given by the increment theory of elastoplasticity. Thus, the finite element equation with the solution of displacement is derived. The assemblage elastoplastic stiffness matrix can be obtained by adding something to the elastic matrix, hence it will shorten the computing time. The determination of every loading increment follows the von Mises yield criteria. The iterative method is used in computation. It omits the redecomposition of the assemblage stiffness matrix and it will step further to shorten the computing time. Illustrations are given to the high-order element application departure from proportional loading, the computation of unloading fitting to the curve and the problem of load estimation.
文摘The cyclic stress-strain responses (CSSR), Neuber's rule (NR) and cyclic strain-life relation (CSLR) are treated as probabilistic curves in local stress and strain method of low cycle fatigue analysis. The randomness of loading and the theory of fatigue damage accumulation (TOFDA) are considered. The probabilistic analysis of local stress, local strain and fatigue life are constructed based on the first-order Taylor's series expansions. Through this method proposed fatigue reliability analysis can be accomplished.
文摘The whole depth measuring plan and its implementation method of surrounding rock mass pressure on the wall′s of a shafts are described, which is in Suncun Coal Mine with a depth of 1 000 m.Then with the combination of data processing, it is discussed the effects of such factors on the distribution law of shaft surrounding rock pressures as rock quality,burying depth, end effect due to excavating, rock stratum dip, shaft wall structure form and regression formulae relating to the shafts surrounding rock pressures as well as to several other factors.And finally, the measured results were verified according to the comparison between analyses of stress strain of side walls and side wall strain measurements.
