R. A. Fontes Valente

A new volumetric and shear locking‐free 3D enhanced strain element

This paper focuses on the development of a new class of eight‐node solid finite elements, suitable for the treatment of volumetric and transverse shear locking problems. Doing so, the proposed elements can be used efficiently for 3D and thin shell applications. The starting point of the work relies on the analysis of the subspace of incompressible deformations associated with the standard (displacement‐based) fully integrated and reduced integrated hexahedral elements. Prediction capabilities for both formulations are defined related to nearly‐incompressible problems and an enhanced strain approach is developed to improve the performance of the earlier formulation in this case. With the insight into volumetric locking gained and benefiting from a recently proposed enhanced transverse shear strain procedure for shell applications, a new element conjugating both the capabilities of efficient solid and shell formulations is obtained. Numerical results attest the robustness and efficiency of the proposed approach, when compared to solid and shell elements well‐established in the literature.

Enhanced Assumed Strain Shell and Solid‐Shell Elements: Application in Sheet Metal Forming Processes

Reliable numerical analysis of sheet metal forming processes using commercial finite element programs involves a variety of fields within computational mechanics area. Material models, contact algorithms, robust and fast incremental and iterative solution techniques are among the key factors that a finite element package must rely upon. Nevertheless, the finite element formulation itself still represents a milestone of crucial importance in the overall quality of the final solution. As sheet metal forming processes present very strong test cases to the performance of finite elements, robust formulations are then desired. In this work, classes of finite elements involving only the Enhanced Assumed Strain (EAS) method are analyzed. Starting from an innovative approach to eliminate transverse shear locking in shell elements (S4E6P5 shell element) and going through a new approach for a volumetric and transverse shear locking‐free solid‐shell element with a low number of internal variables (HCiS12 solid‐shell ...

Fully Integrated EAS-Based Solid-Shell Finite Elements in Implicit Sheet Metal Forming Simulations

In this communication sheet metal forming problems are analyzed with the Finite Element Method and a fully‐integrated solid‐shell element, based on the Enhanced Assumed Strain (EAS) method. Among the solid‐shell element’s distinguish features, it should be mentioned the solely use of the EAS approach in dealing with either transverse and volumetric‐based locking pathologies, thus avoiding the inclusion of other mixed methods into the formulation. The adopted methodology is then able to successfully deal with small thickness shell problems within the incompressible range, aspects commonly appearing in sheet metal forming modeling with solid elements.Simulations of this type of forming processes are mainly solved resorting to membrane and shell‐type finite elements, included in explicit commercial programs. Nevertheless, the presented solid‐shell formulation, within a fully implicit approach, provides reliable solutions when compared to experimental results. It is also worth mentioning that the present soli...