The Static Mechanical Properties of Carbon/Epoxy Composite Laminates with Voids

2013 ◽  
Vol 652-654 ◽  
pp. 29-32
Author(s):  
A Ying Zhang ◽  
Dong Xing Zhang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Composite Laminates ◽  
Epoxy Composite ◽  
Empirical Models ◽  
Compressive Properties ◽  
Cfrp Laminates ◽  
Static Mechanical ◽  
Evolution Laws ◽  
Static Mechanical Properties

The effects of voids on the tensile and compressive properties of CFRP laminates were discussed in this paper. The tensile and compressive strength of specimens decreased with the porosity increasing from 0.33% to 1.50%. The empirical models of the tensile strength and the compressive strength of CFRP laminates with different porosities are established by using ORIGIN software. The evolution laws of the tensile strength and the compressive strength with different porosities were corresponding to the form of exponential function.

scholarly journals Experimental Study on Static Mechanical Properties and Moisture Contents of Concrete Under Water Environment

2019 ◽  
Vol 11 (10) ◽  
pp. 2962 ◽  
Author(s):  
Guohui Zhang ◽  
Xiaohang Li ◽  
Zongli Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Compressive Stress ◽  
Water Saturation ◽  
Splitting Tensile Strength ◽  
Crack Mouth Opening Displacement ◽  
Static Mechanical ◽  
Static Mechanical Properties

This paper presents an experiment to investigate the influence of moisture on the static mechanical properties of concrete, and prediction equations for strength and fracture toughness of concrete at different strength grades, relative to water saturation, were established respectively. The research results show that all of the compressive strength, splitting tensile strength, and fracture toughness of concrete exhibit an approximately linearly decreasing trend with the increase in water saturation. For saturated concrete specimens with w/c 0.65, 0.55, 0.42 compared with dry ones, compressive strength decreases by 40.08%, 36.08%, and 33.73%, respectively, splitting tensile strength decreases by 45.39%, 42.61%, and 35.18%, respectively, and fracture toughness decreases by 57.31%, 49.92%, and 46.76%, respectively. The higher the water saturation of concrete, the larger the slope of the ascending part of the uniaxial compressive stress-strain curve, and the smaller the peak strain corresponding to the peak compressive stress, then in this case, both crack mouth opening displacement and loading point deflection corresponding to the critical load on three-point bending beam, decrease. Ingress of water causes the deformation capacity to decrease, and the toughness to weaken, which are unfavorable to the mechanical properties of concrete.

Damage Characterization in Glass/Epoxy Composite Laminates under Normal and Oblique Planes of Cyclic Indentation Loading with AE Monitoring

2021 ◽  
Vol 79 (1) ◽  
pp. 61-77
Author(s):  
A Jayababu ◽  
V Arumugam ◽  
B Rajesh ◽  
C Suresh Kumar
Keyword(s):  
Compressive Strength ◽  
Acoustic Emission ◽  
Cyclic Loading ◽  
Composite Laminates ◽  
Epoxy Composite ◽  
Damage Resistance ◽  
Damage Initiation ◽  
Residual Compressive Strength ◽  
Cyclic Indentation ◽  
Indentation Damage

This work focuses on the experimental investigation of indentation damage resistance in different stacking sequences of glass/epoxy composite laminates under cyclic loading on normal (0°) and oblique (20°) planes. The stacking sequence, such as unidirectional [0]12, angle ply [±45]6S, and cross ply [0/90]6S, were subjected to cyclic indentation loading and monitoring by acoustic emission testing (AE). The laminates were loaded at the center using a hemispherical steel indenter with a 12.7 mm diameter. The cyclic indentation loading was performed at displacements from 0.5 to 3 mm with an increment of 0.5 mm in each cycle. Subsequently, the residual compressive strength of the post-indented laminates was estimated by testing them under in-plane loading, once again with AE monitoring. Mechanical responses such as peak load, absorbed energy, stiffness, residual dent, and damage area were used for the quantification of the indentation-induced damage. The normalized AE cumulative counts, AE energy, and Felicity ratio were used for monitoring the damage initiation and propagation. Moreover, the discrete wavelet analysis of acoustic emission signals and fast Fourier transform enabled the calculation of the peak frequency content of each damage mechanism. The results showed that the cross-ply laminates had superior indentation damage resistance over angle ply and unidirectional (UD) laminates under normal and oblique planes of cyclic loading. However, the conclusion from the results was that UD laminates showed a better reduction in residual compressive strength than the other laminate configurations.

The Mechanical Property of CFRP Laminates with Voids

2013 ◽  
Vol 652-654 ◽  
pp. 25-28 ◽  
Author(s):  
A Ying Zhang ◽  
Dong Xing Zhang
Keyword(s):  
Mechanical Property ◽  
Exponential Function ◽  
Bending Strength ◽  
Empirical Models ◽  
Cfrp Laminates ◽  
Evolution Laws

The effects of voids on the bending strength and ILSS of CFRP laminates were discussed in this paper. The bending strength and ILSS of specimens decreased with the porosity increasing from 0.33% to 1.50%. The empirical models of the bending strength and ILSS of CFRP laminates with different porosities are established by using ORIGIN software. The evolution laws of the bending strength and ILSS with different porosities were corresponding to the form of exponential function.

Hybrid composites made of unidirectional T600S carbon and E-glass fabrics under quasi-static loading

2016 ◽  
Vol 46 (7) ◽  
pp. 1511-1535 ◽  
Author(s):  
Md. Hasan Ikbal ◽  
Azzam Ahmed ◽  
Wang Qingtao ◽  
Zeng Shuai ◽  
Li Wei
Keyword(s):  
Static Loading ◽  
Composite Laminates ◽  
Failure Strain ◽  
Epoxy Composite ◽  
Hybrid Composites ◽  
Experimental Studies ◽  
Tensile Failure ◽  
Compressive Properties ◽  
Element Analysis ◽  
Hybrid Configuration

Finite element analysis and experimental studies are presented on in-plane tensile and compressive properties under quasi-static loading for two types of hybrid composites made by using unidirectional T620S carbon and E-glass fabrics in a common matrix, epoxy resin. Results are also generated for plain T620S carbon/epoxy and plain E-glass/epoxy composite laminates. Quantitative data for tensile and compressive properties are presented. It is observed that for hybrid composites, placing carbon and glass fiber parts alternately in every layer (intralayer configuration) gives higher tensile and compressive strengths. Tensile failure strain is higher for intralayer compared to interlayer hybrid configuration.

EFFECT OF HYBRIDIZATION ON COMPRESSIVE PROPERTIES OF WOVEN CARBON, GLASS AND KEVLAR HYBRID COMPOSITES

2015 ◽  
Vol 76 (9) ◽  
Author(s):  
Norhafiza Muhammad ◽  
Aidah Jumahat ◽  
Nor Merlisa Ali
Keyword(s):  
Compressive Strength ◽  
Composite Materials ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Composite Structures ◽  
Hybrid Composites ◽  
Optical Microscope ◽  
Strain Diagram ◽  
Compressive Properties ◽  
Modes Of Failure

The growing use of high-performance materials, which are made of hybrid composite systems, has increased rapidly in engineering applications. Hybridization of woven carbon, glass and Kevlar fibre offers better mechanical properties of composite materials. This is also an effective way to reduce the cost of advanced composites. At the moment information on compressive properties of hybrid composites is very limited. It is well known that the compressive strength of composite materials is lower than the tensile strength. Therefore, compressive strength becomes one of the most important criteria in designing composite structures. Therefore, this research is aimed to evaluate the compressive properties of hybrid composites and compare to the properties of neat systems. Hybrid composite samples were fabricated using a vacuum bagging system. The compressive properties of Kevlar hybrid with carbon and glass composites were studied using an INSTRON 3382 universal machine with a constant crosshead speed of 1 mm/min. The compressive properties were determined based on the stress-strain diagram. It was observed that for hybrid composites, placing carbon woven cloth layers in the exterior and Kevlar woven cloth in the interior showed higher compressive strength than placing glass woven cloth layers in the exterior and Kevlar woven cloth in the interior. The modes of failure of the hybrid composite laminates were observed and evaluated using optical microscope and scanning electron microscopy (SEM).

scholarly journals Mechanical Properties and Tensile Fatigue of Graphene Nanoplatelets Reinforced Polymer Nanocomposites

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Ming-Yuan Shen ◽  
Tung-Yu Chang ◽  
Tsung-Han Hsieh ◽  
Yi-Luen Li ◽  
Chin-Lung Chiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Carbon Fiber ◽  
Ultimate Tensile Strength ◽  
Composite Laminates ◽  
Epoxy Composite ◽  
Fiber Composite ◽  
Graphene Nanoplatelets ◽  
Carbon Fiber Composite

Graphene nanoplatelets (GNPs) are novel nanofillers possessing attractive characteristics, including robust compatibility with most polymers, high absolute strength, and cost effectiveness. In this study, GNPs were used to reinforce epoxy composite and epoxy/carbon fiber composite laminates to enhance their mechanical properties. The mechanical properties of GNPs/epoxy nanocomposite, such as ultimate tensile strength and flexure properties, were investigated. The fatigue life of epoxy/carbon fiber composite laminate with GPs-added 0.25 wt% was increased over that of neat laminates at all levels of cyclic stress. Consequently, significant improvement in the mechanical properties of ultimate tensile strength, flexure, and fatigue life was attained for these epoxy resin composites and carbon fiber-reinforced epoxy composite laminates.

Test Matrix for Heat Exposure of Aluminum Alloys at Various Times and Temperatures

2014 ◽  
Vol 354 ◽  
pp. 175-181
Author(s):  
Abdulhamid Al-Abduljabbar ◽  
O.S. Es-Said
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Tensile Strength ◽  
Aluminum Alloys ◽  
General Relation ◽  
Heat Exposure ◽  
Thermal Exposure ◽  
Static Mechanical ◽  
Hardness Values ◽  
Static Mechanical Properties

The purpose of this study is to characterize the effects of heat damage on the electrical conductivity and static mechanical properties of aluminum alloys. The data resulting from the experiments of thermal exposure of several aluminum alloys are used to model the relations that describe the dependence of the electrical conductivity and hardness on the two main variables of these experiments: the temperature and the time of exposure. The dependence of yield strength and ultimate tensile strength on hardness values is characterized. For each case, different materials (alloys) exhibit similar general trends although there are different coefficients for each material to satisfy the general relation.

Evaluation of Tensile Strength of Woven Carbon/Epoxy Composite Laminates at Cryogenic Temperatures Using the Open Hole Specimens

2011 ◽  
Vol 39 (4) ◽  
pp. 103132 ◽  
Author(s):  
M. R. Mitchell ◽  
R. E. Link ◽  
Shinya Watanabe ◽  
Yasuhide Shindo ◽  
Tomo Takeda ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Composite Laminates ◽  
Epoxy Composite ◽  
Cryogenic Temperatures ◽  
Open Hole

scholarly journals Hygro-Thermally Curvature-Stable Free-Layer Composite Laminates with Extension-Twist Coupling

2018 ◽  
Vol 27 (3) ◽  
pp. 096369351802700 ◽  
Author(s):  
D Cui ◽  
D K Li ◽  
S M Zhou
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Composite Laminates ◽  
Differential Evolution Algorithm ◽  
Free Layer ◽  
Strong Constraint ◽  
Buckling Strength ◽  
Coupled Effect ◽  
Layer Composite ◽  
Improved Differential Evolution Algorithm

The tensile strength and compressive strength are indispensable indexes during the design process of composite laminates. For hygro-thermally curvature-stable extension-twist coupled laminates, the improved Differential Evolution Algorithm combined with penalty function is adopted to solve the nonlinear strong constraint of free-layer laminates. The synchronous optimization of multiple targets is achieved, which includes extension-twist coupled effect, tensile strength, compressive strength and buckling strength. Results are presented for free-layer graphite/epoxy composites laminates that consist of 1–18 plies. Finally the hygro-thermal effect, extension-twist coupled effect and buckling strength are simulated and verified.

Effects of Interlaminal Contaminants on Mechanical Properties of Composite Laminates

2011 ◽  
Vol 320 ◽  
pp. 52-57
Author(s):  
Liang Luo ◽  
Dong Li Ma ◽  
Li Gong Zhan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Composite Laminates ◽  
Water Contamination ◽  
Epoxy Composite ◽  
Curing Kinetics ◽  
Curing Temperature ◽  
Oil Contamination ◽  
Water Contaminant ◽  
Dsc Curves

In this paper, the influence of interlaminal contaminations of water, oil and paper on the mechanical properties of carbon fiber reinforced epoxy composite laminates was researched. The results showed that the existence of interlaminal layered contaminations greatly degraded the mechanical properties of composite laminates. The deterioration of mechanical properties resulted from oil contamination was most serious. It was concluded that the ultimate tensile strength (UTS), compression strength and ILSS were more seriously influenced than corresponding modules. How those contaminations affected the mechanical properties was discussed. For further understanding of the effecting mechanism of water contamination on the curing kinetics, the DSC curves of prepregs contaminated by water were compared with that of normal prepregs. It was found that the initial curing temperature of specimens with water contaminant was lower than that of control prepregs.

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