This research presents an experimental and theoretical investigation of the effect of cutouts on the stress and strain of composite laminate plates subjected to static loads. The experimental program covers measurement of the normal strain at the edges of circular and square holes with different number of layers and types of composite materials by using strain gages technique under constant tensile loads. A numerical investigation has been achieved by using the software package (ANSYS), involving static analysis of symmetric square plates with different types of cutouts. The numerical results include the parametric effects of lamination angle, hole dimensions, types of hole and the number of layers of a symmetric square plate. The experimental results show good agreement compared with numerical results. It is found that increasing the number of layers reduces the value of normal strain at the edges of circular and square holes of a symmetric plate and the maximum value of stress occurs at a lamination angle of (30o) and the maximum value of strain occurs at a lamination angle of (50o) for the symmetric square plates subjected to uni-axial applied load. The hole dimensions to width of plates ratio is found to increase the maximum value of stress and strain of a symmetric square plate subjected to uniaxial applied load. Moreover, the value of maximum stress increases with the order of type of circular, square, triangular and hexagonal cutout, whereas the value of maximum strain increases with the order of type of circular, square, hexagonal and triangular cutout.
Viscoelasticity, as its name implies, is a generalization of elasticity and viscosity. Many industrial applications use viscoelastic matrix with reinforcement fiber to obtained better properties. Tensile testing of matrix and one types of fabric polyamide composites was performed at various loading rates ranging from (8.16* 10-5 to 11.66 * 10-5 m/sec) using a servohydraulic testing apparatus. The kind of reinforcement, random glass fiber (RGF), and the kind of matrix, epoxy (E) are used shown that the linear strain (،ـ 0.5) for the three parameter model gives a good agreement with experimental results. The results showed that both tensile strength and failure strain of these matrices and composites tend to decrease with increase of strain rate. The experimental results were comparison with numerical results by using ANSYS 5.4 program for simple study case has shown some agreement. Fracture regions of the tested specimens were also observed to study micro mechanisms of tensile failure.
The aim of current work is to investigate the tensioned composite plates with two types of cutouts. Many industrial applications use composite matrix with reinforcement fiber to obtain better properties. The objective of this work is divided into two parts, first the experimental work covers the measuring of the normal strain (εx) at the edges of (circular & square) holes that are perpendicular to the direction of the applied loads with different number of layers and types of cutouts of composite materials by using strain gages technique under constant tensile loads to compare with the numerical results. The second part is numerical work, which involves studying the static analysis of symmetric square plates with different types of cutout (circular – square). In static analysis, the effect of the following design parameters on the maximum stress (σx), strain (εx) and deflection (Ux) is studied. This part of investigation was achieved by using the software finite element package (ANSYS 5.4).
To control on the operation of sheet metal forming without failure, A diagram is used in which the range accepted, failure and critical deformation range are shown. This diagram is known as the Forming limit diagram. It is considered as one of the important tool to determine the formability of sheet metals. Every sheet metal has its own forming limit diagram which determines its formability, strain limit and the forming regions. In this paper, the forming limit diagrams (FLDs) were experimentally evaluated for low carbon steel sheets with different thickness (0.6, 0.75, 0.85, 1.2mm). The highest limit strain in the forming limit diagram is found in the steel sheet at thickness (1.2mm) and the lowest limits in the steel sheet at (0.6mm), this meaning that the formability improve with increase the thickness of steel sheet. The effect of load punch is higher at biaxial stretch path and the lowest at uniaxial tension path. The load punch is change with different thickness of sheet at the same path. The maximum thinning is found in the biaxial stretch path and the lowest of thinning in plane strain path for all sheets.
A numerical study regarding stress, strain, and deflection of a composite plate is presented. The plate, consisting of three layers of Carbon-, Boron-, and Graphite-Epoxy, was fixed at one end and loaded at the other end in a conventional cantilever configuration. Six arrangements were examined and the spatial distribution of stress, strain, and deflection of the upper surface were calculated. Generally, it was found that the order, by which the three layers are arranged, has a great effect on the response of the plate and the maximum stiffness (in terms of deflection) is achieved when using Epoxy with Graphite-Carbon-Boron as the top-central-bottom layers of the plate.
The demand for strengthening structures becomes necessary when an increase in load is inevitable. For instance very little information is available on the time-dependent behaviour of strengthened concrete columns. Also, this is a primary factor hindering the widespread uses of FRP strengthening technologies in the construction implementations. This paper investigates the behaviour of strengthened concrete columns with FRP sheets subjected to long-term loading by non linear finite element analysis using ANSYS computer package. A three-dimensional finite element model has been used in this investigation. This study achieved a good agreement between numerical and experimental results, it was found that the percentage of error of specimens do not pass (5%) for creep strain. In addition, a parametric study was performed to study the effect of different factors on the behaviour of FRP strengthened concrete columns.
The Cooper-Harper rating of aircraft handling qualities has been adopted as a standard for measuring the performance of aircraft. In the present work, the tail plane design for satisfying longitudinal handling qualities has been investigated with different tail design for two flight conditions based on the Shomber and Gertsen method. Tail plane design is considered as the tail/wing area ratio. Parameters most affecting on the aircraft stability derivative is the tail/wing area ratio. The longitudinal handling qualities criteria were introduced in the mathematical contributions of stability derivative. This design technique has been applied to the Paris Jet; MS 760 Morane-Sualnier aircraft. The results show that when the tail/wing area ratio increases the aircraft stability derivative increases, the damping ratio and the natural frequency increases and the aircraft stability is improved. Three regions of flight conditions had been presented which are satisfactory, acceptable and unacceptable. The optimum tail/wing area ratio satisfying the longitudinal handling qualities and stability is (0.025KeywordsLongitudinal Handling---Stability---Tail Design
Composite laminate plates, fabricated by bonding fiber–reinforced layers, were dynamically analyzed under different combinations of number of layers, type of cutout, hole dimensions, angle of lamination and type of dynamic loading . This work was achieved by the well–known engineering software (ANSYS). The toughness of composite plates was evaluated in terms of the normal stress in the direction of loading at the periphery of the cutout. The toughness was found to increase by increasing the number of layers, by setting the lamination angle at around 40o,by selecting hole dimensions to width of plate ratio of around 0.4 and by employing square cutouts or avoiding triangular cutouts. Also, composite plates were found to be more strain-rate-sensitive in ramp loading, with least number of layers and with triangular type of cutout.
An experimental investigation as well as nonlinear analysis is carried out in this paper to study the behavior of polymer members (Epoxy & Polyester) under direct tension. The ANSYS model accounts for nonlinear phenomenon, such as, Tension Softening Material (TSM) and Enhanced Multilinear Isotropic Softening (EMIS) models. The polymer specimens are modeled using PLANE82 element – eight node plane element – eight node plane element, which is capable of simulating the failure behavior of polymer material members. The intention of this paper is thereby to discuss the proposed softening models to validate the complete Stress-Strain and Load-Deflection response of prismatic specimens subjected to uniaxial tension. The outcomes from the verifications of both modeling techniques have shown good agreement with the experimental results obtained from literature.
Deep beams with rectangular cross-sections are widely used in concrete structures. In the present study, reinforced concrete rectangular deep beams cast with self-compacted concrete (SCC) which contains recycled concrete as coarse aggregate (RCA) were tested under directly and indirectly loading conditions. In the experimental work, fifteen deep beams were investigated, the first parameter considered in this study was the shear span to effective depth (a/d) ratio. The other variable is the replacement ratio by which the normal coarse aggregate is replaced by RCA. The beams were cast without the use of shear reinforcement. During the tests, the response of the beams including the cracking load, the ultimate load, concrete strain, and mid-span deflection were recorded. Test results indicate that the presence of RCA caused a reduction in the values of cracking and ultimate loads. For instance, the cracking load was reduced by 9%, 23%, and 50% and the ultimate load was reduced by 2% , 23%, and 25% as RCA replacement increased by 25%, 50%, and 75% respectively for a/d ratio equals 1.0. Further, by increasing the a/d ratio, the ultimate load was decreased due to the lower contribution of arch action shear transfer in the beam with a higher (a/d) ratio.