Elasto-Plastic Buckling Analysis of Rigidly Jointed Single Layer Reticulated Domes

1992 ◽  
Vol 7 (4) ◽  
pp. 363-368 ◽  
Author(s):  
Toshiro Suzuki ◽  
Toshiyuki Ogawa ◽  
Kikuo Ikarashi

The purpose of this paper is to examine the elasto-plastic buckling behaviours of a rigidly jointed single layer reticulated dome to a static load applied at its centre. The numerical formulation is based on the incremental finite element method incorporating geometric and material nonlinearities. The buckling behaviour is investigated in regard to the shell geometry, the member property and the material property. The nonlinear buckling load and the deformation of the dome are discussed based on parametric study.

Author(s):  
Chithranjan Nadarajah ◽  
Tom Schachinger

A parametric study of square local thin areas on cylindrical shells under external pressure was conducted using finite element method. The study concentrated on both elastic and as well as plastic buckling of the local thin areas. From the study, conservative screening curves were developed to address the structural integrity of the local thin area under external pressure.


2014 ◽  
Vol 4 (4) ◽  
pp. 26-33
Author(s):  
P.Deepak Kumar ◽  
◽  
Ishan Sharma ◽  
P.R. Maiti ◽  
◽  
...  

Author(s):  
Ah-Young Park ◽  
Satish Chaparala ◽  
Seungbae Park

Through-silicon via (TSV) technology is expected to overcome the limitations of I/O density and helps in enhancing system performance of conventional flip chip packages. One of the challenges for producing reliable TSV packages is the stacking and joining of thin wafers or dies. In the case of the conventional solder interconnections, many reliability issues arise at the interface between solder and copper bump. As an alternative solution, Cu-Cu direct thermo-compression bonding (CuDB) is a possible option to enable three-dimension (3D) package integration. CuDB has several advantages over the solder based micro bump joining, such as reduction in soldering process steps, enabling higher interconnect density, enhanced thermal conductivity and decreased concerns about intermetallic compounds (IMC) formation. Critical issue of CuDB is bonding interface condition. After the bonding process, Cu-Cu direct bonding interface is obtained. However, several researchers have reported small voids at the bonded interface. These defects can act as an initial crack which may lead to eventual fracture of the interface. The fracture could happen due to the thermal expansion coefficient (CTE) mismatch between the substrate and the chip during the postbonding process, board level reflow or thermal cycling with large temperature changes. In this study, a quantitative assessment of the energy release rate has been made at the CuDB interface during temperature change finite element method (FEM). A parametric study is conducted to analyze the impact of the initial crack location and the material properties of surrounding materials. Finally, design recommendations are provided to minimize the probability of interfacial delamination in CuDB.


2016 ◽  
Vol 61 (1) ◽  
pp. 149-152 ◽  
Author(s):  
L.W. Żukowska ◽  
A. Śliwa ◽  
J. Mikuła ◽  
M. Bonek ◽  
W. Kwaśny ◽  
...  

The general topic of this paper is the computer simulation with use of finite element method (FEM) for determining the internal stresses of selected gradient and single-layer PVD coatings deposited on the sintered tool materials, including cemented carbides, cermets and Al2O3+TiC type oxide tool ceramics by cathodic arc evaporation CAE-PVD method. Developing an appropriate model allows the prediction of properties of PVD coatings, which are also the criterion of their selection for specific items, based on the parameters of technological processes. In addition, developed model can to a large extent eliminate the need for expensive and time-consuming experimental studies for the computer simulation. Developed models of internal stresses were performed with use of finite element method in ANSYS environment. The experimental values of stresses were calculated using the X-ray sin2ψ technique. The computer simulation results were compared with the experimental results. Microhardness and adhesion as well as wear range were measured to investigate the influence of stress distribution on the mechanical and functional properties of coatings. It was stated that occurrence of compressive stresses on the surface of gradient coating has advantageous influence on their mechanical properties, especially on microhardness. Absolute value reduction of internal stresses in the connection zone in case of the gradient coatings takes profitably effects on improvement the adhesion of coatings. It can be one of the most important reasons of increase the wear resistance of gradient coatings in comparison to single-layer coatings.


Author(s):  
C. Nadarajah

Weld neck flanges on piping systems are susceptible to flange face corrosion when they are exposed to corrosive environments. This paper examines the maximum amount of corrosion a weld neck flange face could tolerate without loosing structural integrity and hence the flange is fit for service. A parametric study using finite element method was used to examine the entire range of weld neck flanges listed in ASME B16.5 Code, Pipe Flanges and Flanged Fittings. From the study, a number of tables were developed limiting the amount of corrosion for the various classes and sizes of flanges.


2017 ◽  
Vol 29 (7) ◽  
pp. 1379-1393 ◽  
Author(s):  
Erasmo Carrera ◽  
Enrico Zappino ◽  
Guohong Li

This article presents a family of one-dimensional finite element method models with node-dependent kinematics for the analysis of beam structures with piezo-patches. The models proposed are built by applying Carrera unified formulation. Carrera unified formulation permits to obtain finite element method stiffness matrices through so-called fundamental nuclei whose form is independent of the assumptions made for the displacement/electrical field over the cross section of a beam. In the previous works, uniform kinematic assumptions have been applied to all the nodes within the same element. The present contribution proposes to use different kinematics on different nodes, leading to node-dependent kinematic finite element method formulations. In such an approach, non-uniform cross sections introduced by piezo-patches can be considered. With the help of layer-wise models, piezoelectric and mechanical domains each can possess individual constitutive relations. Meanwhile, node-dependent kinematics can integrate equivalent single layer models and layer-wise models to reach an optimal balance between accuracy and use of computational resources. Static governing equations for beam elements with node-dependent kinematics accounting for electromechanical effects are derived from the principle of virtual displacements. The competence of the proposed approach is validated by comparing the obtained results with solutions taken from the literature and ABAQUS three-dimensional modelling. Both extension and shear actuation mechanisms are considered.


2013 ◽  
Vol 658 ◽  
pp. 335-339
Author(s):  
Somsak Siwadamrongpong ◽  
Supakit Rooppakhun ◽  
Pakorn Burakorn ◽  
Natchaya Murachai

Presently, large passenger vehicles are known to have high risk of an injury due to accident and insufficient of safety regulation. The strength of seat is one of important issues that affect to injury level of passenger. Therefore, suitable structure strength and design of the seat are very important to prevent injuries and passenger life. This study was to evaluate strength of the seat structure for bus according to preliminary safety regulation of Department of Land Transport. Finite element analysis is employed by using a static load. The seat model was simplified and simulated. Stress and impact scenario between seat-back and back of manikin will be investigated. The strength and deflection of the seat will be evaluated. This study is expected to provide the seat model which will be safe and satisfied according to the regulation.


1992 ◽  
Vol 7 (4) ◽  
pp. 265-273 ◽  
Author(s):  
Toshiro Suzuki ◽  
Toshiyuki Ogawa ◽  
Kikuo Ikarashi

In the present paper, the effect of imperfection on the elastic buckling load and mode shapes of externally-loaded single layer reticulated domes is investigated. The types of buckling concerned here are the general buckling, the local (dimple) buckling and the buckling of a member. As to the geometric parameter of a dome, the slenderness factor S is adopted which represents the openness and slenderness of the dome. The maximum value of the imperfection is assumed to be the normal random variable. The buckling loads are computed by the linear and the nonlinear buckling analysis using the finite element method. The statistical values are calculated by the three-points estimates method. The main points of interest are the influence of the shape and the extent of an imperfection on the buckling load.


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