Stress Analysis Of Composite Plates Research Articles

Stress analysis of composite plate with cutout of various shape

Composite plate found numerous applications in various structures due to its superior properties like high stiffness to weight and strength to weight ratio. Generally, cutouts in these structural elements are unavoidable for many purposes like access to internal parts, ventilation and sometimes to prevent resonance. These geometrical discontinuities in the form of cutouts may be of different shapes and arise nonuniform stress in the plate. Therefore, it becomes necessary to analyse stress concentration factor near cutouts and effect of shape of cutouts on axial deformation and stress distribution for better safety and stability of structure. In the present investigation a Carbon/epoxy composite plate with various shape of cutout subjected to in-plane tensile loading is considered. Finite element based plane stress analysis is used for mathematical modeling. A program for the present analysis is developed in MATLAB. Variation of in-plane displacement and stress concentration factor (SCF) with various shape of cutout is determined. The effect of the geometry of hole on the stress distribution around the hole is also studied. The results of various analyses have been presented with the help of tables, graphs, and nodal plots.

Closed-form methodology for stress analysis of composite plates with cutouts and non-uniform lay-up

This study aims to develop a closed-form methodology for estimating the resultant forces in a finite composite plate, weakened by the presence of elliptical cutouts, under membrane loads. Following an innovative approach, the developed methodology can deal, in the presence of cutouts, with a non-uniform lay-up distribution in the plate. To this end, different laminate features, including the stacking sequence, thickness, and even local reinforcements, will be considered as variable inputs. The main motivation behind this research is to increase the range of applicability of the closed-form methodologies devoted to the structural analysis of composite plates with cutouts, with the purpose of using the present methodology in the first phases of component design.

EXPERIMENTAL AND THEORETICAL STRESS ANALYSIS INVESTIGATION FOR COMPOSITE PLATE UNDER THERMAL LOAD

A paper focuses on the investigation ofthe stress-strain for E-glass fiber /polyester composite plates subjected to the uniform temperature at various factors, such as fiber volume fraction and fiber orientation. To study the stress analysis of composite plate two methods are used: The First method is an experimental test by applying a uniform temperature on the composite plate inside the furnace and a measure the deformation of the plate by using dial gage. The second method based on a finite element solution using ANSYS (ver. 15) program. The results presented here that, the maximum strain in longitudinal direction occurs at a ply angle (90º), whereas the minimum value at a ply angle (0º). However, the maximum strain in transverse direction occurs at a ply angle (0º) whereas the minimum value at a ply angle (90º). In general, the magnitude of thermal strain increases with increasing temperature difference (∆T) and decreases with increasing the fiber volume fraction ( Comparison the results of the experimental test with the numerical analysis of the thermal strain and evaluated the agreement between the two methods used, the maximum discrepancywas 19.7%.

Strength degradation and stress analysis of composite plates with circular, square and rectangular notches using digital image correlation

The design of high performance composite structures frequently includes various shape and size discontinuities for various purposes. The zones near to these notches become critical regions under various working loading. The stress concentration factor (SCF), failure process, delamination, and tensile strength degradation of aluminum as well as in E-glass laminated plates are addressed in the current study through a combination of analytical, experimental and numerical studies using finite element (FE) modeling techniques. In the first part of the current work, a series of tensile tests on laminates with various fiber orientation angles and specimens with different notch diameter/width (D/W) ratios are designed and tested to determine the SCF and fracture mechanisms for unnotched/notched specimens. In addition, strain distribution, failure patterns and damage mechanisms of laminated plates with square and rectangular holes with rounded corners have been investigated. The specimens were manufactured from commercially available aluminum and unidirectional E-glass and Medapoxy STR resin epoxy. Digital Image Correlation (DIC) technique is used to obtain full-field surface strain measurements in notched specimens with different fiber orientations and open hole sizes, in order to show their effects on SCF, failure strength and mechanisms. The strain concentration that allowed damage initiation and failure propagation in the notched laminated plates is obtained experimentally and compared with the simulation details. Furthermore, the effect of the delamination defect around the notch that was unavoidable during hole drilling process was also discussed. In the second part of this study, the experimental data was used to verify the capability of two modified stress criterions models for predicting tensile strength for both materials under consideration. It is shown that the modified models are able to predict tensile strengths of notched samples that display different stress gradients. Compared to experimental data, the accuracy of the predicted strength is within 17%. On the other hand, the numerical outputs from finite element analysis (FEA) compare favorably with experimental results, and give a good estimation for stress distribution compared to the approximate analytical results. This experimental work will be very useful for the validation of new analytical stress calculation models, damage initiation as well as failure propagation models.

Effect of Lamination Angle and Thickness on Analysis of Composite Plate Under Thermo Mechanical Loading

Abstract Analytical formulation and solution of stress analysis of composite plate subjected to thermo mechanical loading for various ply orientation and thickness of lamina are studied. The main aim of the paper is to investigate how mechanical and thermo mechanical loading would affect the stress ratio and stress distribution of composite plate. The plate is composed of layers of glass-epoxy composite and the orientation of the layers is assumed to be antisymmetric about the neutral axis of the laminate. The plate is subjected to a combined mechanical loading of tensile force and moment along x direction. The thermo mechanical stress is calculated for different ply orientation and thickness ratio, subjected to a temperature change and mechanical loading. The effect of number of lamina and varying thickness of laminate on the stress ratio and stress distribution is studied. The results in this paper are obtained by use of MATLAB Programming and by Finite element software ANSYS 14. Results obtained from both the methods are compared. Such type of loading finds wide application in aircraft flying at high altitude, marine application, medical devices etc.

Stress Analysis of Composite Plates with a Quasi-Square Cutout Subjected to Uniaxial Tension

Perforated plates and shells with variously shaped cutout are often used in engineering structures. Despite the importance of the effects of cutout on the load-bearing capacity and stress concentration of such plates little research has focused on stress analysis of plates with special shaped cutout. This study investigates problems associated with the maximum stresses in perforated composite plates with quasi-square shaped cutouts. Analytical solution based on Lekhnitskii’s theory of anisotropic plate is utilized for stress analysis of composite plates with central square shaped cutout. The solution is capable of considering large variety of cutout shapes and loading conditions analytically. Parametric studies were conducted to investigate the effects of variation in cutout bluntness and orientation, material properties, and loading direction on the location and the value of the maximum stress in a flat composite plate subjected uni-axial tension load. Based on results presented herein, the maximum normalized stress of perforated composite plates can be significantly changed by using proper combination of material properties, fiber orientation, loading angle, cutout bluntness, and orientation.

Stress Analysis of Composite Plates with Different Types of Cutouts

Stress Analysis of Composite Plates with Different Types of Cutouts

Stress Analysis of Composite Plates with Non-Circular Cutout

The high stress concentration at the edge of a non-circular shaped cutout is of practical importance in designing of the engineering structures. These types of cutout usually are evaluated either experimentally or numerically. In this paper an attempt is made to formulate a simple analytical method for stress analysis in perforated composite plates with non-circular cutouts. The stress concentration of isotropic and composite perforated plates with variety of centrally located non-circular cutout was investigated. Numerical evaluation using commercial finite element code, were conducted to evaluate the analytical results. Parametric studies were conducted to investigate the effects of variation in cutout shape, bluntness, and material properties on the location and the value of the maximum stress in plates subjected to uni-axial tension load. The results presented herein, indicated that the maximum stress in perforated isotropic/composite plates can be significantly change by using proper material properties, cutout shapes and bluntness.

Stress analysis of perforated composite plates

Thin-walled plates and panels of various constructions find wide use as primary structural elements in simple and complex configuration. In aerospace structures, panels with variously shaped cutout are often used. The understanding of the effects of cutout on the load bearing capacity and stress concentration of such plates is very important in designing of complex structures. An analytical investigation is used to study the stress analysis of plates with different central cutout. Particular emphasis is placed on flat square plates subjected to a uni-axial tension load. The results based on analytical solution are compared with the results obtained using finite element methods. The main objective of this study is to demonstrate the accuracy and simplicity of presented analytical solution for stress analysis of composite plates with central cutout. The effect of cutout geometry (circular, square, or special cutouts), material properties (isotropic and orthotropic), fiber angles, and cutout curvature are considered. The results presented herein, indicated that the presented method can be used to determine accurately the stresses and stress concentration in composite plates with special shape cutouts.