Wei Feng

Bio: Wei Feng is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Bending of plates & Finite element method. The author has an hindex of 2, co-authored 2 publications receiving 19 citations.

A 3-node flat triangular shell element with corner drilling freedoms and transverse shear correction

Abstract: The formulation, implementation and testing of simple, efficient and robust shell finite elements have challenged investigators over the past four decades. A new 3-node flat triangular shell element is developed by combination of a membrane component and a plate bending component. The ANDES-based membrane component includes rotational degrees of freedom, and the refined nonconforming element method-based bending component involves a transverse shear correction. Numerical examples are carried out for benchmark tests. The results show that compared with some popular shell elements, the present one is simple but exhibits excellent all-around properties (for both membrane-and bending-dominated situations), such as free of aspect ratio locking, passing the patch test, free of shear locking, good convergence and high suitability for thin to moderately thick plates. The developed element has already been adopted in a warpage simulation package for injection molding. Copyright © 2011 John Wiley & Sons, Ltd.

Determination method of plastic injection technological parameter and injection moulding machine

Abstract: The present invention relates to a method for setting plastic injection process parameter. Said method includes the following steps: using lots of injection examples as basis and creating example data base, according to plastic injection condition of objective example utilizing example inference method to search the example most approximate to objective example in the example data base so as to obtain the approximate plastic injection process parameter, and utilizing the example to absorb and modify said process parameter so as to define the process parameter of objective example. Said invention also provides an injection moulding machine including injection moulding main machine, memory, process paramete processor and controller.

Development of a strain-smoothed three-node triangular flat shell element with drilling degrees of freedom

Abstract: This paper proposes a three-node triangular flat shell element based on the assumed natural deviatoric strain (ANDES) formulation. The free parameters included in the ANDES formulation are presented for better use of the proposed element in curved shell geometries. In order to further enhance the element behavior, a strain smoothing technique is applied to the derivation of the membrane stiffness of the proposed element. Furthermore, in order to avoid the drill rotation locking that is typically induced by the drilling degrees of freedom, a simple modification factor is introduced. Various benchmark examples are tested in order to verify the performance of the proposed element. Our objective is to improve the performance of the 18DOF triangular shell element.The ANDES formulation is adopted for membrane component.In order to enhance the element behavior further, a strain smoothing technique is applied.To avoid the drill rotation locking, a simple modification factor is introduced.The proposed element is validated using various benchmark problems.

The strain-smoothed MITC3+ shell finite element

Abstract: In this paper, we propose the strain-smoothed MITC3+ shell finite element. The membrane strain field of the continuum mechanics based 3-node triangular shell element (MITC3+) is smoothed using the recently developed strain-smoothed element (SSE) method. The strain-smoothed MITC3+ shell element passes basic tests (patch, isotropy and zero energy mode tests) and shows significantly improved membrane behavior in various numerical examples. The major advantage of the SSE method is that no additional degree of freedom is required for solution improvement.

A novel hybrid shell element formulation (QUAD+ and TRIA+) : a benchmarking and comparative study

Abstract: This paper introduces a novel hybrid finite element (FE) formulation of shell element to enable assembly process simulation of compliant sheet-metal parts with higher efficiency and flexibility. Efficiency was achieved by developing both new hybrid quadrilateral and triangular elements. Quadrilateral element (QUAD+) was formulated by combining area geometric quadrilateral 6 (AGQ6) nodes and mixed interpolated tensorial components (MITC) to model membrane and bending/shear component respectively. Triangular element (TRIA+) was formulated by merging assumed natural deviatoric strain (ANDES) for membrane and MITC for bending/shear component. Flexibility was addressed by developing an open-source C++ code, enhanced by the OpenMP interface for multiprocessing programming. Tests and benchmarks were compiled and executed within Matlab using the MEX API interface. Extensive benchmark studies were accomplished to evaluate the performance of the proposed hybrid formulation and the shell formulations used in three FEM packages - ABAQUS, ANSYS and COMSOL- under static linear elastic condition with small strain assumption. It was observed that the proposed QUAD+ and TRIA+ elements performed better amongst the FE packages, especially when there was in-plane mesh distortion, with errors below 3%. It was also identified that the best efficiency is obtained by adopting dominant QUAD+ elements compared to the TRIA+ when working on complex geometries. This paper also contributes to present a wide set of benchmark studies required to verify new release of FE packages using shell element or evaluate the performance of new shell formulations.

A corotational flat triangular element for large strain analysis of thin shells with application to soft biological tissues

Abstract: A flat triangular element for the nonlinear analysis of thin shells is presented. The formulation relies on (i) a polar decomposition based corotational framework and (ii) a core-element kinematic description adopting the multiplicative superposition of membrane and bending actions. The resulting element is a refined yet simple three-node displacement-based triangle accounting for thickness extensibility and initial shell curvature, and equipped with a fully consistent tangent stiffness. Numerical tests involving shell structures made of rubber-like materials or fibred biological tissues show the effectiveness of the proposed element and its suitability to problems characterized by large displacements, large rotations, large membrane strains and bending. A Matlab toolkit implementing the present formulation is provided as supplementary material.

An efficient flat shell element

Abstract: Up to now, various flat shell’s elements are created by combining plane and bending plate elements. In the case of complicated problems with coarse distorted mesh, only using efficient element leads to the accurate responses. These kinds of the elements are insensitive to the distortion. In fact, they can identify and remove the related errors. In this paper, two internal and boundary fields are deployed in a hybrid functional for formulating the proposed plane element. The method is established 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, and element’s boundary field is achieved by considering the beam behavior. Finally, the high efficiency of author’s element is assessed by solving several numerical samples.