Local Stresses and Thermoelastic Properties of Composite Laminates Containing Micro Cracks

1992 ◽  
pp. 283-308 ◽  
Author(s):  
Peter Gudmundson ◽  
Sören Östlund ◽  
Weilin Zang
Keyword(s):  
Composite Laminates ◽  
Thermoelastic Properties ◽  
Micro Cracks ◽  
Local Stresses

A simple portable low-pressure healant-injection device for repairing damaged composite laminates

2017 ◽  
Vol 45 (4) ◽  
pp. 360-375 ◽  
Author(s):  
WL Lai ◽  
AYH Cheah ◽  
RCO Ruiz ◽  
NGW Lo ◽  
KQJ Kuah ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Composite Laminates ◽  
Low Pressure ◽  
Reinforced Composites ◽  
Injection Device ◽  
Destructive Testing ◽  
Micro Cracks ◽  
Flow Through ◽  
Injection Unit ◽  
Fibre Reinforced Composites

This article presents the outcomes of an undergraduate design-for-industry team-driven project to develop a portable low-pressure healant-injection device. The developed healant-injection device is intended to use for teaching purpose. The students practice some of the techniques of repairing damaged composite laminates, as part of an engineering composite-related course, which mainly covers the fundamentals and applications of composite laminates. The healant-injection device works by introducing resin into damaged site that can assist the healant to flow through the network of micro-cracks in a low-pressure environment. The device comprises three components: a chamber featuring a (rectangular box) cover made from acrylic that is intended to cover a damaged surface in a low-pressure environment, an injection unit and a vacuum pump unit. Only the vacuum chamber was designed from scratch by the team; the other components were sourced commercially. The repair of composite laminates can be performed using a low viscosity resin, which is made to flow through a hole on the roof of the chamber, assisted by the injection unit (fluid dispenser), from which the resin flows into the damaged (micro-cracks) site; the very low pressure environment (25–29 inHg) in the chamber facilitates the removal of air pockets in the cracks. The composite laminates featured in this project are carbon fibre reinforced composite laminates, which are of great interest to the aerospace industry. Testing and evaluation were carried out by the team to assess the performance of the healant-injection device using impacted carbon fibre reinforced composites. To assist the team to study the effectiveness of the repair, (a) an ultrasonic C-scan equipment for non-destructive testing was used to assess the extent of the healant flow into the crack regions within the damaged carbon fibre reinforced composites and (b) a compression after impact test was carried out to assess the recovery of the compressive strength of the repaired carbon fibre reinforced composites compare to the pristine and damaged samples in different number of carbon-fibre plies (10, 16, 24 and 32).

A Micromechanics Model for Thermoelastic Properties of Plain Weave Fabric Composites

1994 ◽  
Vol 116 (4) ◽  
pp. 517-523 ◽  
Author(s):  
H. T. Hahn ◽  
R. Pandey
Keyword(s):  
Representative Volume Element ◽  
Composite Laminates ◽  
Volume Element ◽  
Thermoelastic Properties ◽  
Micromechanics Model ◽  
Plain Weave ◽  
Representative Volume ◽  
Thermal Expansion Coefficients ◽  
Weave Fabric ◽  
Effective Thermal Expansion

A micromechanics model is presented to predict thermoelastic properties of composites reinforced with plain weave fabrics. A representative volume element is chosen for analysis and the fiber architecture is described by a few simple functions. Equations are developed to calculate various phase fractions from geometric parameters that can be measured on a cross section. Effective elastic moduli and effective thermal expansion coefficients are determined under the assumption of uniform strain inside the representative volume element. The resulting model is similar to the classical laminated theory, and hence is easier to use than other models available in the literature. An experimental correlation is provided for a number of Nicalon SiC/CVI SiC and Graphite/CVI SiC composite laminates.

Extended Kantorovich method for local stresses in composite laminates upon polynomial stress functions

2016 ◽  
Vol 32 (5) ◽  
pp. 854-865 ◽  
Author(s):  
Bin Huang ◽  
Ji Wang ◽  
Jianke Du ◽  
Yan Guo ◽  
Tingfeng Ma ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Kantorovich Method ◽  
Extended Kantorovich Method ◽  
Local Stresses ◽  
Stress Functions

Plasticity Analysis of Laminated Composite Plates

1982 ◽  
Vol 49 (4) ◽  
pp. 740-746 ◽  
Author(s):  
Y. A. Bahei-El-Din ◽  
G. J. Dvorak
Keyword(s):  
Composite Laminates ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Plates ◽  
Plastic Behavior ◽  
Elastic Plastic ◽  
Local Stresses ◽  
The Individual ◽  
Hardening Rules ◽  
Yield Conditions

Elastic-plastic behavior of symmetric metal-matrix composite laminates is analyzed for the case of in-plane mechanical loading. The overall response of the laminate at each instant is derived from the elastic-plastic deformation of the individual fibrous layers, and from their mutual constraints. Constitutive equations of the laminated plates are presented in terms of initial yield conditions, hardening rules, and instantaneous compliances. Local stresses, hardening parameters, and strains are found in each lamina and in the fiber and matrix phases within each lamina. Specific results are obtained with the continuum model of elastic-plastic fibrous composites [1] which has been recently developed by the authors. Comparisons of analytical results with experimental measurements are made for certain laminated plates.

Three-dimensional thermoelastic properties of general composite laminates

2017 ◽  
Vol 52 (13) ◽  
pp. 1799-1808 ◽  
Author(s):  
Orzuri Rique ◽  
Johnathan E Goodsell ◽  
Wenbin Yu ◽  
R Byron Pipes
Keyword(s):  
Exact Solution ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Three Dimensional ◽  
Thermoelastic Properties ◽  
Rule Of Mixtures ◽  
Anisotropic Solid ◽  
Complete Set ◽  
Anisotropic Layers

This paper presents a hybrid rule of mixtures for calculating the complete set of effective three-dimensional thermoelastic properties of a composite laminate when it is approximated as an equivalent, homogeneous, anisotropic solid. The laminate can be made of generally anisotropic layers with arbitrary layup sequence. This hybrid rule of mixtures is based on the exact solution obtained using the recently discovered mechanics of structure genome. Since mechanics of structure genome minimizes the loss of accuracy for homogenization, the three-dimensional thermoelastic properties obtained using the mechanics of structure genome-based hybrid rule of mixtures will be the most accurate one could obtain for composite laminates. The results of the hybrid rule of mixtures are compared with several other representative methods for predicting thermoelastic properties of composite laminates.

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