scholarly journals Fatigue behaviour of fibre-reinforced composite T-joints

2018 ◽  
Vol 165 ◽  
pp. 07004
Author(s):  
Ying Wang ◽  
Constantinos Soutis
Keyword(s):  
Fatigue Life ◽  
Testing Machine ◽  
Fatigue Loading ◽  
Maximum Load ◽  
Fatigue Behaviour ◽  
Control Mode ◽  
Static Properties ◽  
T Joints ◽  
Pull Out ◽  
Reinforced Composite

In this paper a study was carried out on the fatigue life of fibre-reinforced composite T-joints subjected to a tensile pull-out loading. The composite T-joints have been made of glass fabric infused with epoxy resin using a vacuum assisted resin transfer moulding technique. Methods such as the use of veil layers, tufting techniques and 3D weave have been employed to improve the interlaminar fracture toughness of the composite T-joints. All the tests were conducted in an Instron testing machine using a specially designed test fixture. Fatigue tests were performed in a load control mode with a stress ratio of R = σmin/σmax = 0.1. The cyclic loading pattern was a sinusoidal wave with a frequency of 6 Hz. The specimens were cycled at a series of constant maximum load values up to failure. Fatigue loads versus life data for each T-joint type were produced at various maximum applied loads. The 3D weave T-joints were found to have the best performance in both static and fatigue loading. Increasing the static properties increases fatigue life performance; the increasing rate in fatigue life is changed with the number of stress cycles. The location for the through-thickness reinforcement plays an important role in improving fatigue life of the Tjoints. Fatigue life is significantly improved if the web is reinforced in through-thickness direction. A finite element (FE) failure model was also created using ABAQUS to determine the location where delamination is initiated and its subsequent propagation.

Fatigue Behaviour of GFRP Reinforced Beams

2021 ◽  
Vol 322 ◽  
pp. 163-169
Author(s):  
Ondřej Januš ◽  
Frantisek Girgle ◽  
Vojtěch Kostiha ◽  
Jan Prokeš ◽  
Petr Štěpánek
Keyword(s):  
Reinforced Concrete ◽  
Fatigue Life ◽  
Concrete Slab ◽  
Fatigue Loading ◽  
Maximum Load ◽  
Fatigue Behaviour ◽  
Constant Load ◽  
Reinforced Concrete Slab ◽  
Reinforced Beams ◽  
Constant Load Amplitude

This article deals with the influence of fatigue loading on the behaviour of GFRP (Glass Fibre Reinforced Polymers) reinforced concrete elements. The aim of the experimental programme is to quantify the effect of fatigue loading on the mechanical properties of GFRP reinforced beams subjected to flexure. The proposed element was a beam simulating the cut-out part of a reinforced concrete slab directly subjected to traffic loading. The dimensions and the amount of reinforcement were adjusted regarding the possibilities of the testing laboratory and to ensure the repeatability of the test. Two different fatigue loading schemes were experimentally verified: a) a constant load amplitude, b) a gradually increasing amplitude. The applied fatigue load with a constant amplitude was designed to achieve a fatigue life of the element ≥ 2×106 cycles. In the case of fatigue loading with an increasing amplitude, the load was increased every 50,000 cycles by 5% of the maximum load in the cycle. The resulting fatigue life was compared to the expected fatigue life determined according to Miner's rule on linear fatigue summation.

Failure of Composite T-Joints in Bending with Through-the-Thickness Reinforcement: Stitching Vs Z-Pinning

2012 ◽  
Vol 525-526 ◽  
pp. 233-236 ◽  
Author(s):  
H. Cui ◽  
Yu Long Li
Keyword(s):  
Energy Absorption ◽  
Present Model ◽  
Failure Process ◽  
Maximum Load ◽  
T Joints ◽  
Pull Out ◽  
Simple Theoretical Model ◽  
Bending Load ◽  
Delamination Resistance ◽  
Mode I Delamination

The stitched composite T-joints and Z-pinned ones subject to bending load were investigated in this paper. A simple theoretical model characterizing the failure process of through the thickness reinforcement (TTR) during mode I delamination was presented. The experimental results showed that the initial damage load and maximum load of stitched specimens are higher than that of Z-pinned ones, while the energy absorption of stitched specimens during delamination is lower than that of Z-pinned ones. The energy absorption values predicted by the present model meet the experiments reasonably well. High friction force at the interface between TTR tow and matrix, with a long pull-out displacement of the tow, helps to improve the delamination resistance.

Effect of sulphate attack on the flexural fatigue behaviour of fly ash–based geopolymer concrete

2018 ◽  
Vol 53 (8) ◽  
pp. 711-718 ◽  
Author(s):  
Tao Long ◽  
Hongen Zhang ◽  
Yu Chen ◽  
Zhi Li ◽  
Jiageng Xu ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fly Ash ◽  
Damage Index ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Distribution Model ◽  
Geopolymer Concrete ◽  
Sulphate Attack ◽  
Flexural Fatigue ◽  
Erosion Effect

In this work, the erosion effect of sulphate solution on the flexural fatigue behaviour of fly ash–based geopolymer concrete was investigated. Under cyclic bending loading, the effect of sulphate attack on the fatigue life of geopolymer concrete was analysed using the static flexural strength as the damage index. Results revealed that the fatigue life of geopolymer concrete after sulphate erosion was significantly reduced compared with uncorroded samples under the same fatigue loading condition. And the fatigue life of corroded/uncorroded geopolymer concrete can be approximately described by the two-parameter Weibull distribution model. Since the sulphate attack would increase the actual stress level of corroded geopolymer concrete, a fatigue equation considering the damage index was deduced to predict the fatigue life of geopolymer concrete after sulphate attack.

scholarly journals Evaluating the Fatigue Resistance of the Innovative Modified-Reinforced Composite Asphalt Mixture

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Gholamali Shafabakhsh ◽  
Mahdi Akbari ◽  
Hossein Bahrami
Keyword(s):  
Fatigue Life ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Fatigue Behaviour ◽  
Road Asphalt ◽  
The Road ◽  
Road Pavement ◽  
Four Point Bending ◽  
Reinforced Composite ◽  
Traffic Loads

Fatigue failure is regarded as one of the most common failures in the road pavement and necessitates spending huge cost annually to maintain the road. Asphalt binder modification and asphalt mixture reinforcement are among the commonly used methods to increase the pavement resistance to a failure caused by fatigue. By proposing a modified-reinforced composite hot mix asphalt (MRC-HMA), the present study aimed to examine the fatigue life of this mixture with one of the most traditional methods (i.e., four-point bending beam fatigue test) and compare it at constant strain conditions and the strain levels of 500, 700, and 900  μ ε and a temperature of 20 ± 0.8 ° C to that of the other three specimens, including control specimens, geogrid-reinforced (GR-HMA) specimens, and nanosilica-modified (NSM-HMA) specimens with 5% nanosilica. In all experiments, the condition to reach the failure stage was assumed equivalent to a 50% reduction in the stiffness coefficient in each load repetition, and the load was applied semisinusoidal at a frequency of 10 Hz without rest. The results showed that the MRC-HMA mixture improved the fatigue life at the strain level of 500  μ s by about 701, 172.5, and 156.4% compared to the control, NSM-HMA, and GR-HMA specimens, respectively. Based on the results, the use of GR-HMA specimens has almost the same results as NSM-HMA ones, but the use of the MRC-HMA mixture can significantly increase the fatigue life of MRC-HMA in all three levels of strain compared to all specimens studied in the present study. Thus, the introduced mixture can be a proper choice for pavements with heavy or light (with a large amount) traffic loads, which usually have a vast adverse effect on the fatigue behaviour of asphalt mixtures.

scholarly journals A new fatigue damage model for pavement concrete beams bearing multi-level bending loads

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255048
Author(s):  
Liang Lei ◽  
Shi Xingang ◽  
Cui Yunhua ◽  
Wang Lefan ◽  
Yan Xiangcheng
Keyword(s):  
Fatigue Life ◽  
Damage Accumulation ◽  
Concrete Beams ◽  
Damage Model ◽  
Testing Machine ◽  
Concrete Specimen ◽  
Fatigue Loading ◽  
Single Stage ◽  
Emission Signal ◽  
Bending Load

MTS-810 material testing machine and acoustic emission signal analyzer were adopted to explore the mechanical behavior of concrete beams broken by the static load and the nonlinear cumulative damage law of concrete beams broken by fatigue bending from single-stage loading. Then, by introducing the Ramesh Talreja’s Damage Criterion, the damage rule of single-stage loading was extended to the damage accumulation rule under multi-stage loading, and the results were verified by the results of two-stage and three-stage fatigue loading tests. Two main conclusions are achieved: first, affected by four-point bending load, the fatigue life of the concrete specimen is in line with the law of the two-parameter Weibull distribution, namely the higher the stress level is, the shorter the fatigue life is. Second, an obvious nonlinear relationship was discovered in the damage of concrete. The model deduced in this paper and the Palmgren-Miner linear damage accumulation model were adopted to compare the test results of flexural fatigue under single, two and three stage loads. The calculation results of this model were more reliable.

scholarly journals Fatigue Lifetime Prediction of Laminated Composites, a Review

2020 ◽  
Vol 9 (3) ◽  
pp. 268-278
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Fiber Type ◽  
Laminated Composites ◽  
Fatigue Loading ◽  
The State ◽  
Reinforced Composites ◽  
Fatigue Lifetime ◽  
Reinforced Composite ◽  
Short Time

It is evident that laminated reinforced composite are successfully prolonging the life of composites compared to particle and fiber type of reinforced composites method. The question on how these laminated composites take up the fatigue loading is crucial in order to give sound confident to industry replacing their design from metal to composites based. The lack of confident and uncertainties’ life of composites components become an issue to designer to shift from metal based to composites based especially when the design required to be done in short time. This review gives a clear picture the state of fatigue life modelling and the life prediction of laminated composites structures. The types of model are favorable when it is accurate, simple and required less input parameters. In the end, this review gives clear pictures on mechanism that involve and the fundamental of formula that available at present.

Effect of Intra-Ply Hybridization of Carbon-Aramid/Epoxy Laminates under Tension-Tension Fatigue Loading

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
B. Ruban Rajasekar ◽  
R. Asokan ◽  
C. Ramesh ◽  
V. Jamin Daniel Selvakumar ◽  
M. Dinesh
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Stress Ratio ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Load Control ◽  
Elongation To Failure ◽  
Superior Mechanical Properties ◽  
Fibre Angle ◽  
Hybrid Carbon

The objective of the research is to investigate the fatigue life of intra-ply hybrid Carbon-Aramid laminate with Epoxy resin in on-axis and off-axis directions. Three different off-axis angles of 15, 30 and 45 degrees were considered for the present work. The intra-ply hybridization is used to combine the superior mechanical properties of Carbon fibre with excellent elongation-to-failure property of Aramid fibre in the same lamina. The fatigue test was performed using load control using a frequency of 5Hz. The fatigue behaviour was studied for Carbon/Epoxy, Aramid/Epoxy, Carbon-Aramid/Epoxy, Carbon-Aramid/Epoxy - 15, Carbon-Aramid/Epoxy - 30 and Carbon-Aramid/Epoxy - 45 with the stress ratio of R = 0.1. The ultimate tensile strength decreases progressively for Carbon/Epoxy, Carbon-Aramid/Epoxy, Aramid/Epoxy, Carbon-Aramid/Epoxy - 15, Carbon-Aramid/Epoxy - 30 and Carbon-Aramid/Epoxy - 45. The effect of off-axis loading indicates that the increase of fibre angle influences the decrease in tensile strength and fatigue life.

scholarly journals Influence of porosity on the fatigue behaviour of additively fabricated TA6V alloys

2018 ◽  
Vol 165 ◽  
pp. 02008 ◽  
Author(s):  
Viet-Duc Le ◽  
Etienne Pessard ◽  
Franck Morel ◽  
François Edy
Keyword(s):  
Fatigue Life ◽  
Additive Manufacturing ◽  
Fatigue Strength ◽  
Pore Size ◽  
Selective Laser Melting ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Laser Melting ◽  
Experimental Campaign ◽  
Porosity Fraction

This work is focused on the influence of porosity when dealing with the fatigue behaviour of the TA6V alloys fabricated by the selective laser melting (SLM) process. The presence of porosity is one of the major issue facing additive manufacturing (AM) of metallic components subjected to fatigue loading. In order to study the effect of porosity on the fatigue behaviour, a vast experimental campaign has been undertaken. These materials are fabricated by the SLM process with different building directions (horizontal, vertical and diagonal) thanks to which specimen batches with different pore sizes are obtained. It is observed that despite a low porosity fraction (around 0.01%), the influence of pores on the fatigue strength of the materials is pronounced. A mapping approach is presented, which links the applied stress, the pore size and the fatigue life. This approach makes it possible to accurately characterize the effect of the porosity size, and also to construct Kitagawa-Takahashi diagrams from S-N data.

Damage Mechanics and Critical Plane Approach to Multiaxial Fatigue

2013 ◽  
Vol 592-593 ◽  
pp. 239-245
Author(s):  
Roberto Brighenti ◽  
Andrea Carpinteri
Keyword(s):  
Fatigue Life ◽  
Damage Mechanics ◽  
Crack Nucleation ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Damage Parameter ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Critical Plane Approach ◽  
Scalar Damage Parameter

The mechanical behaviour of structural components subjected to multiaxial fatigue loading is very important in modern design. Several approaches have been introduced in recent decades to analyse this problem. The so-called critical plane approach, based on the stresses acting on the plane where the crack nucleation is expected to occur, is widely used. This criterion can give us a fatigue damage measurement, which can be used to evaluate fatigue life. On the other hand, fatigue life under general multiaxial stress histories can also be assessed by applying the damage accumulation method. In such a method, a scalar damage parameter is quantified through the damage increments which develop during the fatigue process up to the critical damage value corresponding to the final failure of the structures. The damage increment approach to fatigue has recently been discussed and connected to the classical crack propagation approach. In the present paper, the interpretation of the critical plane approach based on the continuum damage mechanics concepts is examined. In particular, the physical meaning of the critical plane approach is shown, that is, such an approach can be interpreted as a damage method which takes into account the scalar damage parameter evaluated along preferential directions. Finally, the fatigue behaviour of a metallic material under multiaxial cyclic load histories is analysed through the two above approaches.

DIFFERENT GLUELINE THICKNESSES PULL-OUT BEHAVIOUR OF MENGKULANG GLULAM

2016 ◽  
Vol 78 (5-4) ◽  
Author(s):  
Tengku Anita Raja Hussin ◽  
Oon Vincent ◽  
Rohana Hassan
Keyword(s):  
Failure Modes ◽  
Load Capacity ◽  
Testing Machine ◽  
Maximum Load ◽  
Breaking Load ◽  
Glue Line ◽  
Resorcinol Formaldehyde ◽  
Line Thickness ◽  
Pull Out ◽  
Pull Out Strength

Timber connection is still facing inadequacy of engineering studies. Mechanical and adhesive joints are the two main types of connections being used for timber connection. In this study, pull-out strength test is carried to determine the best glue line thickness and the failure modes occur. Three different glue-line thicknesses of 2mm, 3mm and 4mm was tested with holes thicknesses of 14mm, 16mm and 18mm  respectively were drilled on 9 with 3 specimens of each thickness. This test is carried out until failure in the specimen by using the Universal Testing Machine with load capacity of 1000kN and at the rate of 2mm/min. Phenol-resorcinol-formaldehyde (PRF) is the adhesive used for the strengthening purposes with ratio of PRF hardener and resin of 1:5 was used in this experiment. The dowel glued-in steel dowel is 10 mm in diameter from S 235 steel type. For the results; The data shows that glue line thickness of 2mm does generate the highest maximum load compared to 3mm and 4mm of glue line thickness with the value of 2.394kN compared to 2.223kN and 1.789kN respectively. However, glue line thickness of 3mm shows highest breaking load of 1.714kN compared to 1.631kN of 2mm glue line thickness and 1.454kN of 4mm glue line thickness. Therefore, it is proven that the 2mm glue line thickness is more superior in strength and shear stress than 3mm and 4mm of glue line thickness.

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