Papers by Keyword: Buckling

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Authors: Qi Chao Xue, Guang Ping Zou, Ye Wu, Jia Li, Lei Shang
Abstract: Sandwich plate system (SPS) with polyurethane elastomer is more and more used on ship buildings as grillage. A Comparative Study on critical buckling loads between steel grillage and SPS stiffening plate are carried out in this paper. Plate elements and beam elements are used in numerical simulation and a rectangular model is taken as a calculating example. By using of FEA software ANSYS, ultimate buckling loads are calculated with different influential factors between steel grillage and SPS stiffening plate, including the number of stiffening ribs, inertia moment of stiffening ribs, and the thickness of plates. the analysis results of comparison shows that SPS stiffening plates have better performance than steel grillage under in plane compressive loadings.
Authors: Zhe Li, Khoon Siong Ng, Tie Cheng Wu, Xiao Ping Li
Abstract: Measuring deep brain neural activities with a microelectrode is of greatest importance in uncovering the mechanism of various brain disorders. In this operation, a microelectrode needs to be accurately inserted into deep the brain. However, a microelectrode of high flexibility would bend at encountering a layer of tough tissue during insertion, which would lead to deflection and impaired targeting accuracy. To deal with this problem, a rotational insertion method has been developed in this paper for deflection-free insertion. Rotation helps generate a dynamic anti-bending force to prevent buckling, and this force becomes larger with the increase of rotational speed. Thus, by controlling the rotational speed at which insertion is carried out, deflection-free insertion of a microelectrode deep into brain can be realized. The effectiveness of this method has been experimentally confirmed.
Authors: Zhong Hai Xu, Rong Guo Wang, Wen Bo Liu, Cheng Qin Dai, Lu Zhang, Xiao Dong He
Abstract: In this paper, we predict the delamination buckling behavior in slender laminated composite with embedded delamination under compressive load by using the finite element method (FEM). For the different delamination size and depth position, we illustrate the various parameters effects on buckling behavior.
Authors: Rasoul Khandan, Siamak Noroozi, John Vinney, Philip Sewell, Mehran Koohgilani
Abstract: A semi-analytical approach for analysis of laminated plates with general boundary conditions under a general distribution of loads is developed. The non-linear equations are solved by the Newton-Kantorovich-Quadrature (NKQ) method which is a combination of well-known Newton-Kantorovich method and the Quadrature method. This method attempts to solve a sequence of linear integral equations. In this paper this method is used to propose a semi-analytical model for buckling of laminated plates. The convergence of the proposed method is investigated and the validation of the method is explored through numerical examples and the results compared with finite element method (FEM). There is a good agreement between the NKQ model and FEM results.
Authors: Seung Sik Lee, Soo Ha Chae, Soon Jong Yoon, Sun Kyu Cho
Abstract: The strengths of PFRP thin-walled columns are determined according to the modes of buckling which consist of local mode for short columns, global mode for long columns, and interaction mode between local and global modes for intermediate columns. Unlike the local and global buckling, the buckling strength of interaction mode is not theoretically predictable. Refined theoretical approaches which can account for different elastic properties of each plate component consisting of a PFRP thin-walled member are used. Based on both the analytical buckling loads and the experimentally measured buckling loads from literatures, the accuracies of Ylinen’s equation and modified AISC/LRFD column design equation for isotropic steel columns were compared. From the comparison, it was found that the modified AISC/LRFD column design equation is more suitable for the prediction of the buckling loads of PFRP thin-walled members than Ylinen’s equations.
Authors: Jian Hua Ning, Zheng Ping Hai
Abstract: this paper first determines the deformation modes of punching small-hole punches by analyzing the forms of the stress applied to die working parts. It analyzes the disadvantages of existing methods for preventing the buckling problem in punching small holes such as protective jackets and proposes a method for preventing the buckling of punches by reducing the punching force so as to make it possible to punch smaller holes.
Authors: Mark J. Eaton, Karen M. Holford, C.A. Featherston, Rhys Pullin
Abstract: The presence of impact damage in a carbon fibre composite can reduce its capacity to support an in-plane load, which can lead to an unexpected or premature failure. This paper reports on an investigation into two slender carbon/fibre epoxy panels, one un-damaged and one with an artificial delamination introduced using an embedded section of PTFE. The reported tests form part of a larger series of investigations using differing sizes of artificial delamination and real impact damage. An investigation of wave velocity propagation at varying angles to the composite lay up was completed to assist in source location. The specimens were loaded under, uniaxial in-plane loading and monitored using four resonant acoustic emission sensors. A full field optical measurement system was used to measure the global displacement of the specimens. Analysis of AE waveforms and AE hit rate were used to assess the buckling of the panel. The results compared favourably with the optical measurement results.
Authors: Ionel Mircea Cristutiu, Daniel Luis Nunes
Abstract: Steel pitched-roof portal frame with tapered web elements is one of the most commonly used type of structural system low raised buildings where large free spans are required. In practice it is found that the most efficient solution is generally obtained by using tapered web elements, whiles the flanges are kept prismatic. Besides its economic and structural advantages, this refinement brings additional designing challenges for structural engineers: high slenderness of its resulting cross-sections and the uncertainty of results caused by the increased difficulty of a thorough calculation of the resistance to lateral-torsional buckling of tapered I-section elements. If no lateral restraints, or when they are not effective enough, the lateral torsional mode characterizes the global behavior of frame members or interaction with sectional bucking modes may occur. As slenderer sections they are more sensible to buckling (local and global) as well as more sensitive to imperfections than compact sections. The paper summarizes a numerical study performed by authors on a relevant series of such type of elements. Different types of lateral restraints have been considered along with a variety of patterns of initial imperfections. A sophisticate nonlinear inelastic FEM model was built and different imperfections were used to simulate the behavior of the frames.
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