Topic
Limit load
About: Limit load is a research topic. Over the lifetime, 1682 publications have been published within this topic receiving 21305 citations.
Papers published on a yearly basis
1 / 2
Papers
1 Jan 1984
TL;DR: In this article, the authors consider three types of models of increasing complexity: the first model is a perfectly-plastic model, which employs Young's modulus and Poisson's ratio for describing the elastic properties; and a cohesion and a friction angle for the determination of the strength.
Abstract: With reference to practical engineering problems it is shown that considerable differences may be encountered between the results from associated and those from nonassociated plasticity theories. Next, the need for a non-associated plasticity theory is demonstrated by considering test results for sand, concrete and rock. Elementary material parameters are discussed such as Young's modulus and Poisson's ratio for the description of the elastic properties; and a cohesion and a friction angle for the determination of the strength. The salient difference from associated plasticity theory concerns the introduction of a dilatancy angle which controls the inelastic (plastic) volume changes. This dilatancy angle is not only a suitable parameter for the description of soils, but also appears to be useful for concrete and rock. Basically, the paper consists of three parts as we consider three types of models of increasing complexity. The first model is a perfectly-plastic model, which employs the five aforementioned parameters. It is based on test data rather than on Drucker's hypothesis of material stability. The consequences thereof are examined. The second model is a straightforward extension of the first model by augmenting it with friction hardening and cohesion softening. This novel idea is introduced to account for the degradation of the cohesion of cemented granular materials with increasing inelastic deformation. The model is employed in an analysis which shows that plastic deformations tend to localize in thin shear bands, which may occur even before peak strength is reached. Finally, a review is given of concepts for modelling hysteresis and strain accumulation in cyclic loading. The concept of a bounding surface in addition to a yield surface is discussed and is adapted for use in a sophisticated model for loose and cemented granular materials under cyclic loading.
984 citations
TL;DR: In this article, the compressive response of polyester urethane open-cell foams with relative densities of about 0.025 was analyzed using experiments coupled with several levels of modeling.
486 citations
TL;DR: In this paper, a combination of experimentation and analysis is used to identify and study the mechanisms that govern the failure of unidirectional fiber composites under compression, and failure was found to lead to kink bands with distinct orientations and widths.
453 citations
TL;DR: In this article, a method for computing rigorous upper bounds under plane strain conditions is described, based on a linear three-noded triangular element, which has six unknown nodal velocities and a fixed number of unknown multiplier rates, and uses the kinematic theorem to define a kinematically admissible velocity field as the solution of a linear programming problem.
416 citations
TL;DR: In this paper, a technique for computing rigorous upper bounds on limit loads under conditions of plane strain is described, which assumes a perfectly plastic soil model and employs finite elements in conjunction with the upper bound theorem of classical plasticity theory.
Abstract: This paper describes a technique for computing rigorous upper bounds on limit loads under conditions of plane strain. The method assumes a perfectly plastic soil model, which is either purely cohesive or cohesive-frictional, and employs finite elements in conjunction with the upper bound theorem of classical plasticity theory.
The computational procedure uses three-noded triangular elements with the unknown velocities as the nodal variables. An additional set of unknowns, the plastic multiplier rates, is associated with each element. Kinematically admissible velocity discontinuities are permitted along specified planes within the grid. The finite element formulation of the upper bound theorem leads to a classical linear programming problem where the objective function, which is to be minimized, corresponds to the dissipated power and is expressed in terms of the velocities and plastic multiplier rates. The unknowns are subject to a set of linear constraints arising from the imposition of the flow rule and velocity boundary conditions. It is shown that the upper bound optimization problem may be solved efficiently by applying an active set algorithm to the dual linear programming problem.
Since the computed velocity field satisfies all the conditions of the upper bound theorem, the corresponding limit load is a strict upper bound on the true limit load. Other advantages include the ability to deal with complicated loading, complex geometry and a variety of boundary conditions. Several examples are given to illustrate the effectiveness of the procedure.
412 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 3 |
| 2024 | 16 |
| 2023 | 33 |
| 2022 | 52 |
| 2021 | 41 |
| 2020 | 48 |