Objectives: The aim of this study was to assess and compare the characteristics of commonly used initial arch wires by their load DEFLECTION graphs.Materials and Methods: This study tested three wire designs namely copper nickel titanium (CNT), nickel titanium (NiTi), and multi-strand NiTi (MSNT) arch wires engaged in passive self-ligating (PSL) brackets, active self-ligating (ASL) brackets or conventional brackets. To evaluate the mechanical characteristics of the specimens, a three-point bending test was performed. The testing machine vertically applied force on the midpoint of the wire between the central incisor and canine teeth to obtain 2 and 4mm of DEFLECTION. The force level at maximum DEFLECTION and characteristics of plateau (the average plateau load and the plateau length) were recorded. Two-way ANOVA and Tukey’s test were used at P<0.05 level of significance.Results: Force level at maximum DEFLECTION and plateau length were significantly affected by the amount of DEFLECTION. The type of arch wires and brackets had significant effects on force level at maximum DEFLECTION, and plateau length. However, the bracket type had no significant effect on the average plateau force.Conclusion: With any type of brackets in DEFLECTIONs of 2 and 4mm, MSNT wire exerted the lowest while NiTi wire exerted the highest force level at maximum DEFLECTION and plateau phase. The force level at maximum DEFLECTION and the plateau length increased with raising the amount of primary DEFLECTION, however the average plateau force did not change significantly.

A theoretical study has been carried out on sandwich beams strengthened mechanically by two external steel plates attached to their tension and compression sides with so-called ‘‘shear connectors ‘‘. This study is based on the individual behaviour of each component of the composite sandwich section (i.e. reinforced concrete beam and upper steel plate and lower steel plate). The approach has been developed to simulate the behaviour of such beams, and is based on neglecting the separation between the three layers; i.e., the DEFLECTIONs are equal in each element through the same section. The differential equations reached were solved analytically. DEFLECTION was calculated by using the approach for several beams, tested in two series, and close agreements were obtained with the experimental values. Furthermore, the interaction efficiency between the three elements in a composite sandwich beam has been considered thoroughly, from which the effect of some parameters, such as plate length upon the behaviour of such beams, were studied.

Traditional engineering materials lack the necessary properties that are needed in aerospace as well as other modern industries. In order to address the aforementioned problem, a number of different materials are used in concert. With the help of functionally graded material, all the necessary characteristics can be achieved. A fast transition between two different materials can lead to debonding, thermal stresses, residual stresses, and stress concentrations; a gradual change in material properties might mitigate these problems. This work provides a comparison of the analytical solutions for the DEFLECTIONs in Two Dimensional Functionally Graded Taper Beam (2D-FGTB) under a uniformly distributed load, adapting Reddy’s higher-order shear deformation theory. All the material properties of the beam are graded along the thickness and length dimensions using the power-law formula. The thickness of the beam is assumed to change linearly along its length. Equations of motion are derived based on Hamilton's principle and Navier’s solutions. A parametric investigation is conducted to explore the effects of various material and geometrical parameters on the mechanics of 2D-FGTB. These parameters are found to be very significant in studying the static responses of 2D-FGTB.

Different arbitrary shapes of plates are used in civil, marine and aerospace engineering. They may undergo large DEFLECTIONs due to large transverse loads and hence, the nonlinear analysis must be carried out on the structures. In view of the above an elegant finite element formulation is developed for analyzing the geometrically nonlinear static behavior of arbitrary shaped thin plates using superparametric element. This element is capable of accommodating different geometries just like isoparametric element. The efficacy of the element is shown by presenting different numerical examples.

DEFLECTION analysis of a simply supported microbeam subjected to a concentrated load at the middle isinvestigated on the basis of a shear deformable beam theory and non-classical theory. Effects of shear deformationand small size are taken into consideration by hyperbolic shear deformable beam theory and modified straingradient theory, respectively. The governing differential equations and corresponding boundary conditions areobtained by implementing minimum total potential energy principle. Navier-type solution is employed to achievean analytical solution for DEFLECTIONs of simply supported homogeneous microbeams. The effects of sheardeformation, material length scale parameter and slenderness ratio on the bending response of microbeams areinvestigated in detail.