In Sweden, cavity walls constructed with autoclaved aerated concrete (AAC) inner leaves and clay brick outer leaves were a common design choice during the 1950s to 1970s. These walls often result in relatively extensi...
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This paper introduces a novel approach for planning smooth trajectories of robotic manipulators by leveraging multiquadric radial basis functions (MQ-RBFs). The proposed approach aims to achieve optimal trajectories b...
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Externally bonded reinforcement (EBR) was used to increase load bearing capacity of light weight aggregate concrete (LWA) masonry walls subjected to eccentric axial compression. Ladder type masonry reinforcement, high...
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This paper proposes a topology optimization framework for three-dimensional continuum structures subjected to design-dependent loads, including gravity, centrifugal, and hydrostatic pressure loads. First, this study u...
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A general and robust solution procedure for non-linear finite element equations with limit points is developed. At each equilibrium iteration the magnitude of the load is adjusted such that the residual force is ortho...
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A general and robust solution procedure for non-linear finite element equations with limit points is developed. At each equilibrium iteration the magnitude of the load is adjusted such that the residual force is orthogonal to the current displacement increment from the last equilibrium state. The method implements the physical condition that the orthogonal residual force will neither increase nor decrease the magnitude of the current displacement increment vector. The orthogonality condition is formulated directly in terms of conjugate variables and therefore does not contain any scaling parameters. Passage of load and displacement limit points is discussed as well as the relation to line search, minimum residual, and are-length methods. The method is illustrated by two examples.
The fatigue resistance of a single-lap aluminium adhesive joint to cyclic loading in combined shear and bending mode is investigated by nonlinear finite element analysis and crack propagation experiments. The epoxy ad...
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The fatigue resistance of a single-lap aluminium adhesive joint to cyclic loading in combined shear and bending mode is investigated by nonlinear finite element analysis and crack propagation experiments. The epoxy adhesive is modelled by an elasto-plastic overlay material model. The initial cycles build up a residual stress state, leading to nearly linear material behaviour in the following cycles. Fatigue crack propagation is modelled by removing adhesive elements. Two series of experiments with one-sided cyclic load were carried out. The crack length was monitored by measuring the bending compliance around the end of the overlap with clip-gauges. The crack length is determined as a simple linear function of the measured compliance. The experiments show nearly constant rate crack growth until failure, with no appreciable crack initiation period. The rate of crack growth is proportional to the stress level to the power m = 6.2. Fatigue life results are given in the form of S-N curves for adhesive thickness of 0.1 and 0.3 mm. There is no systematic influence of the thickness of the adhesive on the fatigue life. This supports the use of a crack propagation and fatigue life criterion formulated in terms of the energy release rate.
A general format, based on equilibrium states, is developed for the stiffness matrix of elastic beam elements. The stress states are described relative to the line connecting the element end points, whereby the extern...
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A general format, based on equilibrium states, is developed for the stiffness matrix of elastic beam elements. The stress states are described relative to the line connecting the element end points, whereby the external work takes a common form independent of the shape of the beam element. The resulting stiffness matrix is obtained by simple, explicit combinations of a small number of stress energy terms. Examples include a Timoshenko beam with flexible joints, a beam of variable cross-section, and a strongly curved circular beam.
This paper presents an efficient, pointer based profile solver with standard matrix indexing. Constrained equations Ax = b where x contains known and unknown values are solved and the full vectors x and b are obtained...
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This paper presents an efficient, pointer based profile solver with standard matrix indexing. Constrained equations Ax = b where x contains known and unknown values are solved and the full vectors x and b are obtained. Pseudo-code algorithms are formulated for a row oriented form of the LDL(T) factorization and implemented directly as a C code. The solver is implemented in C because of the close relation between two-dimensional arrays and pointers which makes it possible to write a clear and efficient code.
In the orthogonal residual procedure for solution of non-linear finite element equations, the load is adjusted in each equilibrium iteration to satisfy an orthogonality condition to the current displacement increment....
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In the orthogonal residual procedure for solution of non-linear finite element equations, the load is adjusted in each equilibrium iteration to satisfy an orthogonality condition to the current displacement increment. It is shown here that the quasi-Newton formulation of the orthogonal residual method consists of a simple one-term correction of the displacement subincrement, and that this correction leads to orthogonality between the corrected displacement subincrement and the current increment of the internal force vector, thus defining a dual orthogonality algorithm. It is demonstrated how the algorithm can be implemented to combine a single update of the stiffness matrix for each load increment in normal circumstances with full updates locally if increasing stiffness is encountered. The algorithm is illustrated by examples.
A state of plane stress is illustrated by means of two families of curves, each family representing constant values of a derivative of Airy's stress function. The two families of curves farm a map giving in the fi...
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A state of plane stress is illustrated by means of two families of curves, each family representing constant values of a derivative of Airy's stress function. The two families of curves farm a map giving in the first place an overall picture of regions of high and low stress, and in the second place, the map comprises a complete graphic representation of the stress at any point.
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