Buckling load analysis of cracked curved beams using differential quadrature element method

This paper investigates the buckling load of a cracked curved beam subjected to external excitations considering the effects of shear deformations and the geometric nonlinearity due to large deformations. The governing nonlinear equations of motion are derived. The solution consists of just static part, leading to nonlinear differential equations. The differential quadrature element method has been used to solve the problem. First, it is applied to the equilibrium equations, leading to a nonlinear algebraic system of equations that will be solved utilizing an arc length strategy. To verify the validity of the proposed method, the beam is modeled using the finite element method. The great agreement between the results shows the accuracy of the proposed method in predicting the loading of buckling of the beam

A non-dimensional study on both analytic and numeric thermo-elastic behavior of ‎functionally graded thick-walled cylinders under a combination of thermo-‎mechanical loads

Using non-dimensional parameters, the governing equations of the homogeneous and heterogeneous cylinders made of functionally graded material (FGM) were derived under a combination of thermo-mechanical loads. The equations were solved analytically and numerically in a severe temperature and pressure gradient environment. The radial and circumferential stresses together with the radial displacement of FGM cylinder were analytically evaluated and the obtained results of heterogeneous FGM cylinder were compared with conventional homogeneous one. Moreover, in order to assess the accuracy of the derived equations, a numerical solution (NS) was performed using finite element method which was in accordance with the analytical solution (AS). The results of present work show that the use of FGM can optimize the cylinders which are exposed to the joint mechanical and thermal loads

To Improve Total Knee Prostheses Performance Using Three-Phase Ceramic-Based Functionally Graded Biomaterials

One of the common issues that occur after total knee replacement surgery is the aseptic loosening. The problem usually occurs after about 15 years from the surgery. The destructive effects of residual particles due to wear, the stress shielding effect, and micro-movements are the causative factors for this type of loosening. In this research, using the advantages of functionally graded biomaterials (FGBM), it is tried to design a prosthetic system that can reduce the above-mentioned effects. For this purpose, the materials used in the most important part of the prosthesis system, i.e., the femoral part are redesigned so that the bioactivity between the prosthesis and bone, and the stress applied to the adjacent tissues increase simultaneously. In addition, to reduce the effect of wear at contact areas, wear-resistant biocompatible ceramics such as alumina and zirconia are used. The value of stress at the bone-prosthesis interface and adjacent tissues is the most important parameters. Two types of three-phase ceramic-based FGBMs are recommended. The prosthesis with three-phase hydroxyapatite-titanium-zirconia has increased the average stress in the bone tissues around high-risk areas up to 71.8% with respect to a commonly used Cr-Co prosthesis. The result for the prosthesis with three-phase hydroxyapatite-titanium-alumina is up to 65%, respectively. At bone-prosthesis interfaces, an increase of 92% in the stress for both zirconia-based and alumina-based is seen. Briefly, the recommended FGBMs can improve the bone-prosthesis performance in all desired indices

The International Human Epigenome Consortium: A Blueprint for Scientific Collaboration and Discovery.

The International Human Epigenome Consortium (IHEC) coordinates the generation of a catalog of high-resolution reference epigenomes of major primary human cell types. The studies now presented (see the Cell Press IHEC web portal at http://www.cell.com/consortium/IHEC) highlight the coordinated achievements of IHEC teams to gather and interpret comprehensive epigenomic datasets to gain insights in the epigenetic control of cell states relevant for human health and disease. PAPERCLIP