Thick Composite Plates Subjected to Lateral Loading

1987 ◽  
Vol 54 (3) ◽  
pp. 611-616 ◽  
Author(s):  
D. S. Cairns ◽  
P. A. Lagace
Keyword(s):  
Experimental Data ◽  
Analytical Solution ◽  
Experimental Test ◽  
Stress Function ◽  
Orthotropic Plate ◽  
Composite Plates ◽  
Failure Criteria ◽  
Lateral Loading ◽  
Rigid Sphere ◽  
Damage Initiation

An analytical solution for an orthotropic plate subjected to general lateral loading is presented. The solution uses a stress function approach to obtain the localized stresses and strains due to the loading by an axisymmetric rigid sphere. Plots of load versus local indentation are compared with experimental test data previously reported in the literature. The analysis agrees well with the experimental data and could be used in conjunction with failure criteria to predict damage initiation in such a localized region.

scholarly journals Introduction to Macroscopic Optimal Design in the Mechanics of Composite Materials and Structures

2021 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
Aleksander Muc
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Constitutive Relations ◽  
A Priori ◽  
Chemical Properties ◽  
Composite Plates ◽  
Failure Criteria ◽  
Lagrange Equations ◽  
Homogenization Methods ◽  
Mechanics Of Composite Materials

The main goal of building composite materials and structures is to provide appropriate a priori controlled physico-chemical properties. For this purpose, a strengthening is introduced that can bear loads higher than those borne by isotropic materials, improve creep resistance, etc. Composite materials can be designed in a different fashion to meet specific properties requirements.Nevertheless, it is necessary to be careful about the orientation, placement and sizes of different types of reinforcement. These issues should be solved by optimization, which, however, requires the construction of appropriate models. In the present paper we intend to discuss formulations of kinematic and constitutive relations and the possible application of homogenization methods. Then, 2D relations for multilayered composite plates and cylindrical shells are derived with the use of the Euler–Lagrange equations, through the application of the symbolic package Mathematica. The introduced form of the First-Ply-Failure criteria demonstrates the non-uniqueness in solutions and complications in searching for the global macroscopic optimal solutions. The information presented to readers is enriched by adding selected review papers, surveys and monographs in the area of composite structures.

Stress Concentrations in Cylindrically Orthotropic Composite Plates With a Circular Hole

1981 ◽  
Vol 48 (3) ◽  
pp. 563-569 ◽  
Author(s):  
N. J. Hoff
Keyword(s):  
Closed Form ◽  
Circular Hole ◽  
Orthotropic Plate ◽  
Composite Plates ◽  
Stress Concentrations ◽  
Orthotropic Composite ◽  
Closed Form Solutions ◽  
Cylindrically Orthotropic

The equations governing the distribution of the stresses in a cylindrically orthotropic plate with a circular hole are solved for the case when the plate is subjected to uniform uniaxial traction. Closed-form solutions are given for the circumferential stresses along the edge of the hole.

Probabilistic Finite-Element Analysis of S2-Glass Epoxy Composite Beams for Damage Initiation Due to High-Velocity Impact

2016 ◽  
Vol 2 (4) ◽  
Author(s):  
Shivdayal Patel ◽  
Suhail Ahmad ◽  
Puneet Mahajan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Velocity ◽  
Laminated Composite ◽  
Composite Plates ◽  
High Velocity Impact ◽  
Element Analysis ◽  
Fiber Failure ◽  
Velocity Impact ◽  
Damage Initiation

The safety predictions of composite armors require a probabilistic analysis to take into consideration scatters in the material properties and initial velocity. Damage initiation laws are used to account for matrix and fiber failure during high-velocity impact. A three-dimensional (3D) stochastic finite-element analysis of laminated composite plates under impact is performed to determine the probability of failure (Pf). The objective is to achieve the safest design of lightweight composite through the most efficient ply arrangement of S2 glass epoxy. Realistic damage initiation models are implemented. The Pf is obtained through the Gaussian process response surface method (GPRSM). The antisymmetric cross-ply arrangement is found to be the safest based on maximum stress and Yen and Hashin criteria simultaneously. Sensitivity analysis is performed to achieve the target reliability.

A General Correlation for Pool Film Boiling Heat Transfer From a Horizontal Cylinder to Subcooled Liquid: Part 2—Experimental Data for Various Liquids and Its Correlation

1990 ◽  
Vol 112 (2) ◽  
pp. 441-450 ◽  
Author(s):  
A. Sakurai ◽  
M. Shiotsu ◽  
K. Hata
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Analytical Solution ◽  
Boiling Heat Transfer ◽  
Radiation Effects ◽  
Approximate Analytical Solution ◽  
Horizontal Cylinder ◽  
Film Boiling ◽  
System Pressure ◽  
Horizontal Cylinders

Experimental data of pool film boiling heat transfer from horizontal cylinders in various liquids such as water, ethanol, isopropanol, Freon-113, Freon-11, liquid nitrogen, and liquid argon for wide ranges of system pressure, liquid subcooling, surface superheat and cylinder diameter are reported. These experimental data are compared with a rigorous numerical solution and an approximate analytical solution derived from a theoretical model based on laminar boundary layer theory for pool film boiling heat transfer from horizontal cylinders including the effects of liquid subcooling and radiation from the cylinder. A new correlation was developed by slightly modifying the approximate analytical solution to agree better with the experimental data. The values calculated from the correlation agree with the authors’ data within ± 10 percent, and also with other researchers’ data for various liquids including those with large radiation effects, though these other data were obtained mainly under saturated conditions at atmospheric pressure.

scholarly journals Semi-analytical solution for the problem of extended Pom-Pom fluid flow in a round pipe

2021 ◽  
Vol 2057 (1) ◽  
pp. 012007
Author(s):  
A I Kadyirov ◽  
E K Vachagina
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Analytical Solution ◽  
Solution Method ◽  
Parametric Method ◽  
Single Equation ◽  
Weissenberg Number ◽  
Normal Stresses ◽  
Rheological Equation ◽  
Rheological Equation Of State

Abstract A semi-analytical solution to the problem of the steady flow of viscoelastic single equation eXended Pom-Pom (XPP) fluid in a round pipe using the four-mode rheological equation of state of XPP is presented. An original parametric method for solving the set problem is used. The resulting method is applicable for solving a similar problem in a flat slit. The developed solution method is tested by comparing it with numerical results and experimental data. Using a polyacrylamide solution as an example, the influence of the Weissenberg number on the axial velocity profiles and the components of normal stresses is studied.

Investigation of Bending Fatigue of Composite Plates by Using Infrared Thermography

2011 ◽  
Vol 268-270 ◽  
pp. 406-411 ◽  
Author(s):  
Ömer Sinan Şahin ◽  
Murat Selek ◽  
Şirzat Kahramanlı
Keyword(s):  
Infrared Thermography ◽  
Heat Generation ◽  
Temperature Rise ◽  
Epoxy Composite ◽  
Composite Plates ◽  
Fatigue Loading ◽  
Thermal Camera ◽  
Thermal Images ◽  
Bending Fatigue ◽  
Damage Initiation

In this study, the temperature rise of composite plates with a hole during fatigue loading was investigated. Woven glass/epoxy composite plates with eight plies were subjected to bending fatigue loading and materials were observed by using a thermal camera during the test. Previous works showed that a heat generation can form due to internal friction and damage formation. Therefore, a thermographic infrared imaging system was used to detect the temperature rise of composite specimens. During the tests, the thermal images of the specimens have been recorded by a thermal camera and then transferred to the image processing program which has been developed by using MATLAB. By using these thermal images, the spot temperatures of the specimen were obtained by using artificial neural networks. The obtained temperatures show local increase at places where the heat generation localized. These regions considered being the probable damage initiation sites. It is shown in this study that most probable damage initiation zones in the woven glass/epoxy composite material can be detected by using infrared thermography (IRT) approach prior to failure.

PROGRESSIVE DAMAGE FAILURE ANALYSIS OF POST-BUCKLED COMPOSITE SINGLE-STRINGER PANEL WITH TEFLON INSERTS

2021 ◽  
Author(s):  
VIJAY K. GOYAL ◽  
AUSTIN PENNINGTON ◽  
JASON ACTION
Keyword(s):  
Experimental Data ◽  
Composite Structures ◽  
Laminated Composites ◽  
Compressive Loading ◽  
Weight Ratio ◽  
High Strength ◽  
Material Model ◽  
Stiffened Panels ◽  
Damage Initiation ◽  
Critical Aspects

The high strength-to-weight and stiffness-to-weight ratio materials, such as laminated composites, are advantageous for modern aircraft. Laminated composites with initial flaws are susceptible to delamination under buckling loads. PDA tools help enhance the industry’s understanding of the mechanisms for damage initiation and growth in composite structures while assisting in the design, analysis, and sustainment methods of these composite structures. The global-local modeling approach for the single-stringer post-buckled panel was evaluated through this effort, using Teflon inserts to simulate the defect of damage during manufacturing. This understanding is essential for designing the post-buckled structure, reducing weight while predicting damage initiation location, and addressing a potential design review for future aircraft repairs. In this work, the initial damage was captured with Teflon inserts as the starting configuration; and any reference to the damage initiation refers to any damage beyond the “initial unbonded region.” The effort aims to develop, evaluate, and enhance methods to predict damage initiation and progression and the failure of post-buckled hat-stiffened panels using multiple Abaqus FEA Virtual Crack Closure Technique (VCCT) definitions. Validation of the PDA using the VCCT material model was performed on a large single-stringer panel subjected to compressive loading. The compressive loading of the panel caused the skin to buckle before any damage began to occur locally. In addition, comparisons are made for critical aspects of the damage morphology, such as a growth pattern that included delamination from the skin-stiffener interface to the skin and ply interfaces. When compared against the experimental data produced through the NASA Advanced Composites Project (ACP), the present model captured damage migration from one surface to another, and model validations were ~5% of the experimental data.

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