scholarly journals The effect of temperature on fatigue strength and damage of FRP composite laminates

2021 ◽  
Author(s):  
Hossein Mivehchi
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Damage Model ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Frp Composites ◽  
Frp Composite

The present study intends to investigate the effect of temperature on cumulative fatigue damage of laminated fibre-reinforced polymer (FRP) composites. The effect of temperature on fatigue damage is formulated based on a previously proposed residual stiffness fatigue damage model. The fatigue strength of FRP composite laminates is also formulated to have temperature dependent parameters. The research work is divided into three main parts; the first part reviews the fatigue damage mechanism is fibre-reinforced composites based on stiffness degradation. The recent residual stiffness of Varvani-Shirazi was used as the backbone structure of damage analysis in this thesis. This model is capable of damage assessment while the effects of maximum stress, stress ratio and fibre orientation of FRP composites were recognized. The Varvani-Shirazi damage model was further developed to assess fatigue damage of FRP composites at various temperatures (T). Inputs of the damage model are temperature dependent parameters including Young's modulus (E), ultimate tensile strength(ðult) and fatigue life (Nf). As the next part of the proposed analysis, the temperature dependency of each parameter is formulated, and the relations of E-T and ðult-T are substituted in the Varvani-Shirazi fatigue model. Finally, all terms and equations are evaluated with the experimental data available in the literature. Six sets fatigue data were used in this thesis to evaluate fatigue of FRP specimens. The predicted results were found to be in good agreement with the experimentally obtained data. The proposed fatigue damage model was found promising to predict the fatigue damage of unidirectional (UD) and women FRP composites at different temperatures. Temperature dependant parameters of Young's modulus, ultimate tensile strength, and S-N diagram were also found to be responsive when used of UD, cross-ply, and quasi-isotropic FRP laminates.

scholarly journals The effect of temperature on fatigue strength and damage of FRP composite laminates

2021 ◽  
Author(s):  
Hossein Mivehchi
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Damage Model ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Frp Composites ◽  
Frp Composite

The present study intends to investigate the effect of temperature on cumulative fatigue damage of laminated fibre-reinforced polymer (FRP) composites. The effect of temperature on fatigue damage is formulated based on a previously proposed residual stiffness fatigue damage model. The fatigue strength of FRP composite laminates is also formulated to have temperature dependent parameters. The research work is divided into three main parts; the first part reviews the fatigue damage mechanism is fibre-reinforced composites based on stiffness degradation. The recent residual stiffness of Varvani-Shirazi was used as the backbone structure of damage analysis in this thesis. This model is capable of damage assessment while the effects of maximum stress, stress ratio and fibre orientation of FRP composites were recognized. The Varvani-Shirazi damage model was further developed to assess fatigue damage of FRP composites at various temperatures (T). Inputs of the damage model are temperature dependent parameters including Young's modulus (E), ultimate tensile strength(ðult) and fatigue life (Nf). As the next part of the proposed analysis, the temperature dependency of each parameter is formulated, and the relations of E-T and ðult-T are substituted in the Varvani-Shirazi fatigue model. Finally, all terms and equations are evaluated with the experimental data available in the literature. Six sets fatigue data were used in this thesis to evaluate fatigue of FRP specimens. The predicted results were found to be in good agreement with the experimentally obtained data. The proposed fatigue damage model was found promising to predict the fatigue damage of unidirectional (UD) and women FRP composites at different temperatures. Temperature dependant parameters of Young's modulus, ultimate tensile strength, and S-N diagram were also found to be responsive when used of UD, cross-ply, and quasi-isotropic FRP laminates.

scholarly journals Fatigue Strength of Acacia Mangium

2019 ◽  
pp. 29-32
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Endurance Limit ◽  
Acacia Mangium ◽  
Vertical Axis ◽  
Life Cycles ◽  
Grain Angle ◽  
Sinusoidal Waveform ◽  
Fatigue Endurance

The works in this study is to investigate and understand the nature of Acacia mangium axial fatigue strengths under repeated stress. Acacia mangium trees were cut to produce oven-dried Small Clear Specimens that were then tested until fracture in parallel to the grain direction. This was carried out in order to discover its Ultimate Tensile Strength, which was later identified as 143.87 MPa, in parallel to the grain direction (0° grain angle). In the next phase, specimens were tested for fatigue strengths in repeated-tensile sinusoidal waveform loading at 100 Hz frequency. The stress levels for this test were at the ratios of 80, 60, 40, 30, 20 and 10% of the Ultimate Tensile Strength (0° grain angle) for the construction of Life (N) - Stress (S) plots and empirical correlation. It was observed that the Acacia Mangium N-S (Wöhler) plots have an exponential correlation with the N – intercept of vertical axis at five (5) million cycles, while the intercept of horizontal, S – axis, was at 143.87 MPa. The study also observed that Acacia mangium achieves 106 life cycles at 10% stress level. For this reason, it is concluded that the material has a fatigue endurance limit at 10% of the Ultimate Tensile Strength for 0° grain angle.

scholarly journals Microtomographic Analysis of Impact Damage in FRP Composite Laminates: A Comparative Study

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
M. Alemi-Ardakani ◽  
A. S. Milani ◽  
S. Yannacopoulos ◽  
L. Bichler ◽  
D. Trudel-Boucher ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Impact Damage ◽  
Glass Fibers ◽  
Impact Testing ◽  
Frp Composites ◽  
Frp Composite ◽  
Flexural Testing ◽  
Close Relationship ◽  
High Level ◽  
Tomographic Analysis

With the advancement of testing tools, the ability to characterize mechanical properties of fiber reinforced polymer (FRP) composites under extreme loading scenarios has allowed designers to use these materials in high-level applications more confidently. Conventionally, impact characterization of composite materials is studied via nondestructive techniques such as ultrasonic C-scanning, infrared thermography, X-ray, and acoustography. None of these techniques, however, enable 3D microscale visualization of the damage at different layers of composite laminates. In this paper, a 3D microtomographic technique has been employed to visualize and compare impact damage modes in a set of thermoplastic laminates. The test samples were made of commingled polypropylene (PP) and glass fibers with two different architectures, including the plain woven and unidirectional. Impact testing using a drop-weight tower, followed by postimpact four-point flexural testing and nondestructive tomographic analysis demonstrated a close relationship between the type of fibre architecture and the induced impact damage mechanisms and their extensions.

Terahertz Ray Nondestructive Characterizations in FRP Composites

2010 ◽  
Vol 123-125 ◽  
pp. 839-842 ◽  
Author(s):  
Je Woong Park ◽  
Kwang Hee Im ◽  
David K. Hsu ◽  
Chien Ping Chiou ◽  
Daniel J. Barnard
Keyword(s):  
Composite Laminates ◽  
Electromagnetic Properties ◽  
Reflection Mode ◽  
Frp Composites ◽  
Frp Composite ◽  
Application Systems ◽  
Spectroscopy System ◽  
Terahertz Ray ◽  
Characterization Procedure ◽  
Good Agreement

Recently, terahertz ray imaging has emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques, and new application systems are under processing development for the area applications. In this study, a new time-domain spectroscopy system was utilized for detecting and evaluating layup effect and flaw in FRP composite laminates. Extensive experimental measurements in reflection mode were made to map out the T-ray images. Especially in this characterization procedure, we estimated the electromagnetic properties such as the refractive index. Estimates of properties are in good agreement with known data. Furthermore layup effect and flaw of FRP composite laminates were observed in reflection mode and limitations will be discussed in the T-ray processing.

Fatigue Life Prediction of Composite Laminate

2012 ◽  
Vol 472-475 ◽  
pp. 591-595 ◽  
Author(s):  
Jun Liu ◽  
Feng Peng Zhang
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Life Prediction ◽  
Plate Theory ◽  
Damage Model ◽  
Prediction Method ◽  
Fatigue Life Prediction ◽  
Fatigue Properties ◽  
Adjacent Layer

Abstract. based on the accumulating fatigue damage model, with single ply plate theory and experiment data as the foundation, consider the interaction between adjacent layer and material degradation, a kind of fatigue life prediction method of fiber reinforced composite laminates is developed. The stiffness decline of each ply during cyclic loading is determined by the fatigue damage variable and the load amplitude and the fatigue life of any laminates can be predicted using the fatigue properties of single ply plate. Using this method a 3D Finite element model is established by ABAQUS software and the fatigue life and the fatigue damage evolution of a T300 / QY8911 laminats are analyzed, the results are more closer to the experimental results.

The effect of temperature on fatigue damage of FRP composites

2010 ◽  
Vol 45 (14) ◽  
pp. 3757-3767 ◽  
Author(s):  
H. Mivehchi ◽  
A. Varvani-Farahani
Keyword(s):  
Fatigue Damage ◽  
Effect Of Temperature ◽  
Frp Composites

The fatigue and ultimate tensile strengths of metals between 4⋅2 and 293° K

1957 ◽  
Vol 242 (1229) ◽  
pp. 203-211 ◽  
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Brittle Fracture ◽  
Low Temperatures ◽  
Fatigue Characteristics

The fatigue of copper, silver, gold, aluminium, magnesium, zinc and iron has been investigated at 4⋅2, 20, 90 and 293° K. Except for zinc and iron, which exhibit brittle fracture at low temperatures, the fatigue characteristics improve very considerably as the temperature is reduced. The ultimate tensile strength of all the metals was also taken at each temperature and there was shown to be a marked correlation between the increase in the tensile strength at low temperatures and the increase in the fatigue strength. The results are discussed with reference to current ideas on the mechanism of fatigue.

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.

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