A degenerate solid element formulation for large deformations of thin shell structures

Author(s):  
Tau Wu ◽  
Walter Horn ◽  
Tau Wu ◽  
Walter Horn
2015 ◽  
Vol 12 (02) ◽  
pp. 1550004 ◽  
Author(s):  
N. V. Swamy Naidu ◽  
B. Sateesh

The development of a new four node 24 degree of freedom bilinear degenerated shell element is presented for the analysis of shell structures. The present finite element formulation considers the assumed covariant transverse shear strains to avoid the shear locking problem and the assumed covariant membrane strains, which are separated from covariant in-plane strains, to overcome the membrane locking problem. The formulation also includes the deviation of the normal torsional rotation of the mid surface in the governing equation. This element is free from serious shear and membrane locking problems and undesirable spurious kinematic deformation modes. The element is tested for rigid body modes and distorted edges to meet the patch test requirements. The versatility and accuracy of this new degenerated shell element is demonstrated by solving several numerical examples for thick and thin plates.


Author(s):  
Haigui Fan ◽  
Wenguang Gu ◽  
Longhua Li ◽  
Peiqi Liu ◽  
Dapeng Hu

Buckling design of axially compressed cylindrical shells is still a challenging subject considering the high imperfection-sensitive characteristic in this kind of structure. With the development of various design methods, the energy barrier concept dealing with buckling of imperfection-sensitive cylindrical shells exhibits a promising prospect in recent years. In this study, buckling design of imperfection-sensitive cylindrical shells under axial compression based on the energy barrier approach is systematically investigated. The methodology about buckling design based on the energy barrier approach is described in detail first taking advantage of the cylindrical shells whose buckling loads have been extensively tested. Then, validation and discussion about this buckling design method have been carried out by the numerical and experimental analyses on the cylindrical shells with different geometrical and boundary imperfections. Results in this study together with the available experimental data have verified the reliability and advantage of the buckling design method based on energy barrier approach. A design criterion based on the energy barrier approach is therefore established and compared with the other criteria. Results indicate that buckling design based on energy barrier approach can be used as an efficient way in the lightweight design of thin-shell structures.


2017 ◽  
Vol 869 ◽  
pp. 50-61
Author(s):  
Matthias Sabel ◽  
Christian Sator ◽  
Ralf Müller ◽  
Benjamin Kirsch

The formation of chips in cutting processes is characterised by large deformations and large configurational changes and therefore challenges established modeling techniques. To overcome these difficulties, the particle finite element method (PFEM) combines the benefits of discrete modeling techniques with methods based on continuum mechanics. In this work an outline of the PFEM, as well as an explanation of the finite element formulation are provided. The impact of the boundary detection on the structural integrity is studied. The numerical examples include a tensile test as well as cutting simulations. The paper is concluded by a comparison of cutting forces with analytical results.


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