Fatigue Damage in On-Axis and Off-Axis Woven-Fiber/Resin Composite

2011 ◽  
Vol 488-489 ◽  
pp. 230-233
Author(s):  
John Montesano ◽  
Zouheir Fawaz ◽  
Kamran Behdinan ◽  
Cheung Poon
Keyword(s):  
Resin Composite ◽  
Damage Mechanism ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Woven Fabric ◽  
Test Results ◽  
Damage Development ◽  
Strain Behaviour ◽  
Observed Behaviour ◽  
High Degree

In this study the tensile static and fatigue behaviour of a woven-fabric laminate is investigated in both the on-axis and off-axis material directions. Emphasis is placed on the development of damage and its influence on the stress-strain behaviour of the laminate. The test results illustrate that there is a high degree of anisotropic behaviour due to anisotropic damage development, which is evident by the variation of the material behaviour between the on-axis and off-axis test specimens. The fatigue tests also suggest that the on-axis specimens exhibit noticeable stiffness degradation, while the off-axis specimens do not. The qualitative results provide significant insight into the type of damage mechanism responsible for the observed behaviour.

Fatigue Damage Evaluation in CFRP Woven Fabric Composites Through Dynamic Modulus Measurements

2004 ◽  
Author(s):  
Hideaki Kasano ◽  
Osamu Hasegawa ◽  
Chiaki Miyasaka
Keyword(s):  
Fatigue Damage ◽  
Material Properties ◽  
Elastic Moduli ◽  
Fatigue Loading ◽  
Damage Function ◽  
Fatigue Tests ◽  
Woven Fabric ◽  
Damage Development ◽  
Dynamic Elastic Moduli ◽  
Number Of Cycles

Advanced fiber reinforced composite materials offer substantial advantages over metallic materials for the structural applications subjected to fatigue loading. With the increasing use of these composites, it is required to understand their mechanical response to cyclic loading [1–4]. Our major concern in this work is to macroscopically evaluate the damage development in composites during fatigue loading. For this purpose, we examine what effect the fatigue damage may have on the material properties and how they can be related mathematically to each other. In general, as the damage initiates in composite materials and grows during cyclic loading, material properties such as modulus, residual strength and strain would vary and, in many cases, they may be significantly reduced because of the progressive accumulation of cracks. Therefore, the damage can be characterized by the change in material properties, which is expected to be available for non-destructive evaluation of the fatigue damage development in composites. Here, the tensiontension fatigue tests are firstly conducted on the plain woven fabric carbon fiber composites for different loading levels. In the fatigue tests, the dynamic elastic moduli are measured on real-time, which will decrease with an increasing number of cycles due to the degradation of stiffness. Then, the damage fimction presenting the damage development during fatigue loading is determined from the dynamic elastic moduli thus obtained, from which the damage function is formulated in terms of a number of cycles and an applied loading level. Finally, the damage function is shown to be applied for predicting the remaining fifetime of the CFRP composites subjected to two-stress level fatigue loading.

scholarly journals Cyclic fatigue behaviour of hydrothermally aged 3Y-TZP ceramics in 4-point bending tests

2021 ◽  
Vol 15 (2) ◽  
pp. 184-194
Author(s):  
Renato Souza ◽  
Roberto Duarte ◽  
Manuel Alves ◽  
Juliana Daguano ◽  
Santos dos ◽  
...  
Keyword(s):  
Bending Strength ◽  
Ceramic Materials ◽  
Cyclic Fatigue ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Bending Test ◽  
Test Results ◽  
Transformation Toughening ◽  
Bending Tests ◽  
M Phase

Fatigue is one of the most important properties to be considered in ceramic dental implants due to cyclic mechanical stresses arising from the chewing process. In this work, the fatigue behaviour of hydrothermally degraded ZrO2-based ceramics stabilized with 3mol% Y2O3 (3Y-TZP) was studied in 4-point bending tests. Samples of 3Y-TZP were compacted (100MPa), sintered at 1475 ?C for 2 h, polished and hydrothermally degraded in an autoclave as described in the ISO-13356 standard. The samples were characterized by their relative density, crystalline phase composition, microstructure and surface roughness. The highly dense (>99.6%TD) sintered 3Y-TZP ceramics has only tetragonal t-ZrO2 phase, even after hydrothermal ageing. Furthermore, the ceramic materials presented a Vickers hardness of 12.7?0.2GPa, a fracture toughness of 7.1?0.3MPa?m1/2 and a 4-point bending strength of 940.1?67MPa. Based on the bending test results 5 different stress levels for the fatigue tests were selected and conducted by cyclic 4-point bending obtaining the S-N curve. Weibull statistics was used for the statistical analysis. The fatigue tests indicate that the limit of fatigue resistance of this 3Y-TZP ceramics is around 550MPa, i.e. higher than the limits established in the ISO-13356 standard for the use of Y-TZP ceramics for the manufacture of implants. The fatigue behaviour of the investigated 3Y-TZP ceramics was related to the toughening mechanisms acting in Y-TZP ceramics, such as transformation toughening related to t?m phase transformation and microcracking.

The fatigue behaviour of fibrous composite materials

1989 ◽  
Vol 24 (4) ◽  
pp. 235-244 ◽  
Author(s):  
P T Curtis
Keyword(s):  
Composite Materials ◽  
High Performance ◽  
Fibrous Composite ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Damage Development ◽  
Reinforced Composite ◽  
Organic Matrices ◽  
Development Processes ◽  
Laminated Materials

The fatigue behaviour of high performance continuous fibre reinforced composite materials based on organic matrices has been reviewed. Methods of performing fatigue tests are discussed. Fatigue damage development processes are reviewed for typical unidirectional and laminated materials and fatigue performance compared for different materials. The effects of stress concentrators and environmental exposure are considered and the use of alternative forms of composite such as woven materials discussed. A comparison with the fatigue of metals is made.

scholarly journals Numerical Simulation of the Fatigue Behaviour of a Friction Stirred Channel Aluminium Alloy

2018 ◽  
Vol 165 ◽  
pp. 21008
Author(s):  
Catarina Vidal ◽  
Ricardo Baptista ◽  
Virgínia Infante
Keyword(s):  
Maximum Stress ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Single Step ◽  
Test Results ◽  
Friction Stir ◽  
Paris Law ◽  
Critical Areas ◽  
Crack Propagation Direction ◽  
Crack Growth Curve

Friction stir channelling (FSC) is one of the most promising innovations based on the friction stir concepts. FSC uses a non-consumable tool, similar to that used to perform the friction stir welding (FSW) process, to produce continuous and integral channels, with any path, in monolithic aluminium alloys components in a single step. This paper presents the mechanical behaviour of friction stirred channel components in particular the fatigue resistance of the channels analysed. Finite element analyses were performed taking into account the maximum stress values applied in experimental fatigue tests of the aluminium components. The energy release rate for different crack lengths was obtained using the software ABAQUS. The fatigue crack growth curve was established according to the Paris Law, and the crack propagation direction was calculated using the maximum tangential stress (MTS) criterion. During the analysis it was observed that the critical areas are located in the vicinity of the channels corners, as it was observed in the fracture surfaces of the experimental fatigue test results.

scholarly journals Fretting Fatigue Behaviour of Alloy Steel in the Very High Cycle Region

2019 ◽  
Vol 300 ◽  
pp. 18002
Author(s):  
Yoshinobu Shimamura ◽  
Reo Kasahara ◽  
Hitoshi Ishii ◽  
Keiichiro Tohgo ◽  
Tomoyuki Fujii ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Fatigue Behaviour ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Test Results ◽  
Torsional Fatigue ◽  
Very High

It is well known that fretting fatigue strength is much lower than the fatigue strength of smooth specimens and the fatigue limit disappears. Many studies on fretting fatigue have been reported but most of the studies have not cover fatigue properties in the very high cycle regime more than 107 cycles. In this study, an accelerated fretting fatigue testing method was developed by using an ultrasonic torsional fatigue testing machine with a clamping fretting pad. Fretting fatigue tests of CrMo steel were conducted by using the developed method. Test results showed that fretting fatigue failure occurs in the very high cycle region.

Effect of Shape of Fiber Bundle on Damage Development of Woven Fabric Composities

2006 ◽  
Vol 55 (2) ◽  
pp. 224-229 ◽  
Author(s):  
Takao OTA ◽  
Hikaru YOSHIZUMI ◽  
Hirokazu TSUCHIHASHI ◽  
Takashi MATSUOKA ◽  
Kazuhiko SAKAGUCHI
Keyword(s):  
Fiber Bundle ◽  
Woven Fabric ◽  
Damage Development

An improved nonlinear model considering relative velocity for the friction behavior between untwisted glass-fiber tow and roller

2021 ◽  
pp. 004051752110308
Author(s):  
Yang Liu ◽  
Zhong Xiang ◽  
Xiangqin Zhou ◽  
Zhenyu Wu ◽  
Xudong Hu
Keyword(s):  
Friction Coefficient ◽  
Glass Fiber ◽  
Relative Velocity ◽  
Friction Model ◽  
Woven Fabric ◽  
Test Results ◽  
Application Process ◽  
Friction Behavior ◽  
Improved Model

Friction between the tow and tool surface normally happens during the tow production, fabric weaving, and application process and has an important influence on the quality of the woven fabric. Based on this fact, this paper studied the influence of tension and relative velocity on the three kinds of untwisted-glass-fiber tow-on-roller friction with a Capstan-based test setup. Furthermore, an improved nonlinear friction model taking both tension and velocity into account was proposed. According to statistical test results, firstly, the friction coefficient was found to be positively correlated with tension and relative velocity. Secondly, tension and velocity were complementary on the tow-on-roller friction behavior, with neither being superior to the other. Thirdly, an improved model was found to present well the nonlinear characteristics between friction coefficient and tension and velocity, and predicational results of the model were found to agree well with the observations from Capstan tests.

Fatigue Behaviour of Friction Stir Welded Steel Joints

2014 ◽  
Vol 891-892 ◽  
pp. 1488-1493 ◽  
Author(s):  
José Azevedo ◽  
Virgínia Infante ◽  
Luisa Quintino ◽  
Jorge dos Santos
Keyword(s):  
Base Material ◽  
Welding Process ◽  
Steel Structures ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Welded Steel ◽  
Shipbuilding Industry ◽  
Friction Stir ◽  
Steel Joints

The development and application of friction stir welding (FSW) technology in steel structures in the shipbuilding industry provide an effective tool of achieving superior joint integrity especially where reliability and damage tolerance are of major concerns. Since the shipbuilding components are inevitably subjected to dynamic or cyclic stresses in services, the fatigue properties of the friction stir welded joints must be properly evaluated to ensure the safety and longevity. This research intends to fulfill a clear knowledge gap that exists nowadays and, as such, it is dedicated to the study of welded steel shipbuilding joints in GL-A36 steel, with 4 mm thick. The fatigue resistance of base material and four plates in as-welded condition (using several different parameters, tools and pre-welding conditions) were investigated. The joints culminate globally with defect-free welds, from which tensile, microhardness, and fatigue analyses were performed. The fatigue tests were carried out with a constant amplitude loading, a stress ratio of R=0.1 and frequency between 100 and 120 Hz. The experimental results show the quality of the welding process applied to steel GL-A36 which is reflected in the mechanical properties of joints tested.

A Reliability-Based Approach to Assess Fatigue Behaviour Based on Small Incomplete Data Sets

2008 ◽  
Vol 44-46 ◽  
pp. 871-878 ◽  
Author(s):  
Chu Yang Luo ◽  
Jun Jiang Xiong ◽  
R.A. Shenoi
Keyword(s):  
Incomplete Data ◽  
Standard Procedure ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Small Sample ◽  
Data Sets ◽  
Safe Life ◽  
A New Technique ◽  
And Performance

This paper outlines a new technique to address the paucity of data in determining fatigue life and performance based on reliability concepts. Two new randomized models are presented for estimating the safe life and pS-N curve, by using the standard procedure for statistical analysis and dealing with small sample numbers of incomplete data. The confidence level formulations for the safe and p-S-N curve are also given. The concepts are then applied for the determination of the safe life and p-S-N curve. Two sets of fatigue tests for the safe life and p-S-N curve are conducted to validate the presented method, demonstrating the practical use of the proposed technique.

Effects of T5 and T6 Heat Treatments Applied to Rheocast A356 Parts for Automotive Applications

2008 ◽  
Vol 141-143 ◽  
pp. 237-242 ◽  
Author(s):  
Mario Rosso ◽  
Ildiko Peter ◽  
R. Villa
Keyword(s):  
Fatigue Behaviour ◽  
Cyclic Stress ◽  
Industrial Applications ◽  
Fatigue Tests ◽  
Controlled Cooling ◽  
Test Analysis ◽  
Heat Treated ◽  
Mechanical Performances ◽  
Semi Solid ◽  
Number Of Cycles

The correlation between the evaluation of the mechanical and of the fatigue behaviour of the rheocast, T5 and T6 heat treated SSM A356 aluminium alloy with respect to the microstructures of the component has been investigated. The study has been carried out on a suspension arm injected in a rheocasting 800 tons plant in Stampal S.p.A. The new rheocasting is a process that allows obtaining the alloys in a semisolid state directly from the liquid state, by controlled cooling of the molten alloys. The resulting microstructures are very fine, free from defects and homogeneous: these characteristics improve the mechanical properties of the alloys and specially the response to cyclic stress, an important issue for a suspension component. After a preliminary tensile test analysis, axial high frequency fatigue tests have been carried out at room temperature on specimen cut out from the suspension arm to determine the Wöhler curve and the number of cycles to failure. The results of this work allow a comparison of the effects of heat treatment process, T5 or T6, on Semi-Solid components for industrial applications in the automotive field. On the basis of these analysis the correlation between microstructure and mechanical performances can be established.

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