, the optimization constraints of insensitivity to distortion, rotational invariance and not having parasitic shear error are employed. In addition, the equilibrium equations will be established based on some constraints among the strain states. The authors...

. The number of the strain states decreases when the conditions among strain states are satisfied. Several numerical tests are used to demonstrate the performance of the proposed elements. Famous elements, which were suggested by other researchers, are used...

Various corotational schemes for solid, shell, bending plate and beam elements have been proposed so far. Nevertheless, this approach has rarely been utilized for membrane problems. In this paper, a new quadrilateral element ...

In this paper, a plane quadrilateral element with rotational degrees of freedom is developed. Present formulation is based on a hybrid functional with independent boundary displacement and internal optimum strain field. ...

based on the optimum strain states. Furthermore, Trefftz functionals for independent internal and boundary fields are employed to formulate the suggested bending element. In this procedure, the optimum strain states construct the internal field...

matrix of the frame element. In the proposed

method, some virtual inelastic springs are attached to the elastic element. Such springs model plasticity in the

strain states beyond the rigid body modes of the element. The stiffness matrix...

matrix of

the frame element. In the proposed method, some virtual inelastic springs are attached to the

elastic element. Such springs model plasticity in the strain states beyond the rigid body modes

of the element. The stiffness...

A new four-sided element is proposed for plane stress and strain problems. This generalized shape

element is formulated based on the strain states. Error assessment, improvement and increase of the

efficiency can conveniently...