Element Model For Static Analysis Research Articles

A modified quasi-3D theory and mixed beam element method for static behaviour analysis of functionally graded beams

This paper develops a modified quasi-3D theory and the mixed beam element model for static analysis of functionally graded beams. The modified quasi-3D theory encompasses two innovations. Firstly, the accurate distribution of transverse shear stress is derived from the differential equilibrium equation that describes the relationship between stresses, rather than the traditional one derived from geometric relations and constitutive equations. Secondly, the effect of distributed loads associated with transverse stretching deformation, a factor typically overlooked in the existing quasi-3D theory-based beam models, is involved. In the development of beam finite element model, the mixed variational principle is firstly utilized to formulate the model of a quasi-3D theory-based beam element, where generalized displacements and internal forces are treated as two types of independent field quantities. Two numerical examples are conducted to investigate the validity and accuracy of the proposed theory and beam element. Numerical results indicate that the proposed mixed beam element can accurately predict the stress distributions over the cross-section and produce accurate displacement solutions. Meanwhile, it is noted that the effect of distributed loads related to the transverse stretching deformation should be correctly considered in the analysis of functionally graded beams based on quasi-3D theory.

A finite element model for static analysis of curved thin-walled beams based on the concept of equivalent layered composite cross section

In this study, an accurate 1D finite element model with low degrees of freedom (DOFs) is presented for the static extensional-shearing-bending analysis of curved thin-walled beams. In order to incorporate the nonclassical effects like transverse shear flexibility in the formulation, the concept of equivalent layered composite cross section (ELCS) is employed. Based on this new concept, the cross section of a thin-walled beam is replaced with an equivalent layered composite one. A global–local layered beam theory is employed to describe the displacement fields of the curved beams. A curved beam finite element with three nodes and 13 DOFs is developed for the approximation of the unknown variables of the displacement fields. For validation of the proposed model, the results of 1 D models of other researchers as well as the results of the 2D/3D finite element simulations (ABAQUS) are employed. Needlessness to the shear correction factor, satisfaction of zero-conditions of shear stresses on the upper and lower planes of the curved beam, high accuracy in the prediction of structural responses, and significant reduction in the time of computations are some of distinct features of the proposed finite element model.

CAD-Based Bit Design for Inner Wall Descaling of Water Injection Pipe

Water pipeline scaling serious by prolonged use, result in a substantial diameter narrowed, reduced water efficiency. In order to solve this problem, analyzes the deposition feature and the dill descaling method, research on dill descaling theory and chip formation process. Choose multi-tooth bit as a foundation. According to the characteristics of processing object, improved the structure and cutting teeth distribution, get a new type of scaling drill. Take the inside wall of injection pipe and scale as research object, established finite element model for static analysis, get stress graph and stress curve, showed the wall stress state in drilling process.

Modeling of torsion actuation of beams using inclined piezoelectric actuators

The present work is preliminary studies on the development of finite element model for static analysis of advanced beam structure subjected to axial, transverse, and torsion loads in addition to the torsion actuation due to the piezoelectric actuators. These types of smart structures can be used as element of mechanical system, helicopter rotor blade, and/or blades for turbomachinery. The equation of motion of the structure system is derived using the energy variation approach. The model assumes that the structure behaves as a Bernoulli–Euler beam in bending and extension, while torsion is introduced by utilizing a cross-sectional warping function, which dependent upon the cross- section geometry of the structure. A linear and hermit cubic shape functions are used to model the axial and transverse deformations, while quadratic interpolation shape function is introduced to model the torsion deformation. The bending, torsion, and axial coupling are introduced in the stiffness and mass matrices. The electric potential is considered as function of the thickness and the length of the beam element. A MATLAB interactive code is developed to validate the model. The obtained results are compared to the available analytical and finite element results and found reasonable.

Optimization Design Research on Descaling Bit of Water Pipeline Wall

Water pipeline scaling serious by prolonged use, result in a substantial diameter narrowed, reduced water efficiency. Mechanical cleaning is a kind of economic and security cleaning method, current drilling scaling equipment cannot clean effectively. In order to solve this problem, analyzes the dill descaling method. Choose multi-tooth bit as a foundation. Established finite element model for static analysis, gets three direction force diagram. Optimal design drill structure, created a new type of scaling drill. Compared two kinds force analysis results, by improving the structure, distributed stress on multiple cutting tooth, improved cutting conditions, enhanced the drill descale and feed ability, and improved the working life of the unit. Carried out static and dynamic finite element analysis, provide a theoretical basis for follow-up design.

A layerwise mixed least-squares finite element model for static analysis of multilayered composite plates

A layerwise finite element model is developed in a mixed least-squares formulation for static analysis of multilayered composite plates. The model assumes a layerwise variable description of displacements, transverse stresses and in-plane strains, taken as independent variables. The mixed formulation allows to completely and a priori fulfil the known C z 0 requirements, which refer to the zig-zag form of displacements in the thickness direction and the interlaminar continuity of transverse stresses, due to compatibility and equilibrium reasons, respectively. This contrasts with layerwise displacement-based models that usually cannot a priori account for the interlaminar continuity of transverse stresses. In addition, the benefit of mixed least-squares formulation, as opposed to mixed weak form models, is that it leads to a variational unconstrained minimization problem, where the finite element approximating spaces can be chosen independently. Numerical examples are shown to assess the layerwise mixed least-squares model predictive capabilities compared to three-dimensional elasticity solutions and also other finite element results available in literature. Most notably, the present model is able to achieve accurate results in very good agreement with three-dimensional solutions and is shown to be insensitive to shear-locking.