Abstract:The extended bond-based peridynamic （XPD） model resolved the limitation of fixed Poisson’s ratio in the classical model for small deformation problems. In this paper， a novel implementation using the finite deformation formulation is proposed to deal with geometrical nonlinear problems. The rotation of solid is calculated by the polar decomposition of the deformation gradient tensor derived from the least square fitting of the local displacement field. Therefore， the deformed part of the bond deflection can be separated from the general displacements， and then correct large deformation predictions can be obtained by integrating each bond force of the deformed system. Several benchmark studies are presented to demonstrate the predictive ability of the proposed model.

Abstract:Based on the theories of Timoshenko’s beams and Vlasov’s thinwalled members, a new geometrically nonlinear beam element model is developed by placing an interior node in the element and applying independent interpolation to bending angles and warp, in which factors such as shear deformation, coupling of flexure and torsion, and second shear stress are all considered. Thereafter, geometrical nonlinear strain in TotalLagrangian is formulated and geometrical stiffness matrix is deduced. Examples manifest that the developed model is accurate and feasible in analyzing thinwalled structures.

Abstract:Combined with a project example of flexible giant Ferris wheel,mechanical performance of rim and cable was analyzed.The rational initial prestressing force was chosen to optimize the structural behaviour.The initial imperfection was considered to perform the stability analysis of rim and overall structure.Nonlinear buckling characteristics was researched.Taking both the geometrical and material nonlinearity into account,the elasto-plastic limit bearing capacity analysis was carried out and its results comprehensively revealed the structural characteristics.The results of analytical study indicate that nonlinear characteristics of flexible giant Ferris wheel is obvious due to the introduction of prestressed cable.Mechanical performance of the structure depends on the initial prestressing force.The wheel consisting of radiate spoke cables and space truss provides strong lateral stiffness as well as torsional stiffness and the stability performance is favorable.The mechanism of plastic development is appropriate and its failure mode belongs to the strength failure.The elasto-plastic limit bearing capacity is so large that the wheel can satisfy the need both for operating condition and for storm condition.