Modifikasi Teknik Discrete Shear Gap Pada Elemen Balok Timoshenko Berbasis Kriging

Metode elemen hingga berbasis Kriging (MEH-K) yang dikembangkan oleh Plengkhom & Kanok-Nukulchai adalah salah satu pengembangan dari metode elemen hingga (MEH). Seperti yang diperkirakan tenyata dalam analisis MEH-K untuk balok dan pelat lentur, fenomena shear locking masih terjadi. Adapun kesimpulan dari pengujian elemen balok Timoshenko yang menggunakan MEH-K dengan teknik discrete shear gap (DSG) berhasil mengeliminasi fenomena shear locking, tetapi hanya berlaku untuk shape function cubic. Adanya penelitian ini adalah untuk memodifikasi teknik DSG pada elemen balok Timoshenko berbasis Kriging agar bebas dari fenomena shear locking. Dari penelitian ini, didapatkan bahwa dengan memodifikasi teknik DSG, elemen balok Timoshenko berbasis Kriging dengan orde berapapun bebas dari fenomena shear locking yaitu menghasilkan nilai deformasi yang akurat dan nilai gaya geser yang berbentuk piecewise constant

Locking-free two-layer Timoshenko beam element with interlayer slip

A new locking-free strain-based finite element formulation for the numerical treatment of linear static analysis of two-layer planar composite beams with interlayer slip is proposed. In this formulation, the modified principle of virtual work is introduced as a basis for the finite element discretization. The linear kinematic equations are included into the principle by the procedure, similar to that of Lagrangian multipliers. A strain field vector remains the only unknown function to be interpolated in the finite element implementation of the principle. In contrast with some of the displacement-based and mixed finite element formulations of the composite beams with interlayer slip, the present formulation is completely locking-free. Hence, there are no shear and slip locking, poor convergence and stress oscillations in these finite elements. The generalization of the composite beam theory with the consideration of the Timoshenko beam theory for the individual component of a composite beam represents a substantial contribution in the field of analysis of non-slender composite beams with an interlayer slip. An extension of the present formulation to the non-linear material problems is straightforward. As only a few finite elements are needed to describe a composite beam with great precision, the new finite element formulations is perfectly suited for practical calculations. (c) 2007 Elsevier B.V. All rights reserved

Lmit and shakedown analysis based on solid shell models

The paper treats the formulation of the shakedown problem and, as special case, of the limit analysis problem, using solid shell models and ES-FEM discratization technology. In this proposal the Discrete shear gap method is applied to alleviate the shear locking phenomenon

Application of continuum laws in discontinuity analysis based on a regularised displacement jump

The application of continuum constitutive laws in embedded strong discontinuity analysis is examined. By adopting a regularised discontinuity (approximating the unbounded strain field resulting from a displacement jump with a bounded function), the strain field in a body is always bounded, hence continuum laws can be applied. However, this must be done with some caution since the ‘fictitious’ strain state at the discontinuity can lead to spurious behaviour that does not arise in the conventional application of classical constitutive laws. Particularly addressed is stress locking as a function of the displacement regularisation in some plasticity models. It is also shown that the regularisation function can have a serious impact on convergence behaviour for some types of constitutive models