Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were establi...Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were established. Analytic solutions of combined differential equations were also established. Partial degree of freedom was adopted to establish a new FEA element of three-dimensional beam, taking into account the slip effect. Slip and its first-order derivative were introduced into the nodes of composite box beams as generalized degree of freedom. Stiffness matrix and load array of beam elements were established. A three-dimensional nonlinear calculation program was worked out. The results show that the element is reliable and easy to divide and is suitable for special nonlinear analysis of large-span composite box beams.展开更多
We study the effect of ＂ghost forces＂ for a quasicontinuum method in three dimension with a planar interface. ＂Ghost forces＂ are the inconsistency of the quasicontinuum method across the interface between the atom...We study the effect of ＂ghost forces＂ for a quasicontinuum method in three dimension with a planar interface. ＂Ghost forces＂ are the inconsistency of the quasicontinuum method across the interface between the atomistic region and the continuum region. Numerical results suggest that ＂ghost forces＂ may lead to a negilible error on the solution, while lead to a finite size error on the gradient of the solution. The error has a layer-like profile, and the interfacial layer width is of O（ε）. The error in certain component of the displacement gradient decays algebraically from O（1） to O（ε） away from the interface. A surrogate model is proposed and analyzed, which suggests the same scenario for the effect of ＂ghost forces＂. Our analysis is based on the explicit solution of the surrogate model.展开更多
基金Project(50708112) supported by the National Natural Science Foundation of ChinaProject(IRT1296) supported by the Program for Changjiang Scholars and Innovative Research Team in University
文摘Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were established. Analytic solutions of combined differential equations were also established. Partial degree of freedom was adopted to establish a new FEA element of three-dimensional beam, taking into account the slip effect. Slip and its first-order derivative were introduced into the nodes of composite box beams as generalized degree of freedom. Stiffness matrix and load array of beam elements were established. A three-dimensional nonlinear calculation program was worked out. The results show that the element is reliable and easy to divide and is suitable for special nonlinear analysis of large-span composite box beams.
基金supported by National Natural Science Foundation of China(Grant Nos.1093201191230203 and 11021101)
文摘We study the effect of ＂ghost forces＂ for a quasicontinuum method in three dimension with a planar interface. ＂Ghost forces＂ are the inconsistency of the quasicontinuum method across the interface between the atomistic region and the continuum region. Numerical results suggest that ＂ghost forces＂ may lead to a negilible error on the solution, while lead to a finite size error on the gradient of the solution. The error has a layer-like profile, and the interfacial layer width is of O（ε）. The error in certain component of the displacement gradient decays algebraically from O（1） to O（ε） away from the interface. A surrogate model is proposed and analyzed, which suggests the same scenario for the effect of ＂ghost forces＂. Our analysis is based on the explicit solution of the surrogate model.
