Experimental investigation on the rotating bending fatigue behaviour of glass and carbon fibre-reinforced epoxy composites

2021 ◽  
pp. 1-15
Author(s):  
Hemanth Kumar C ◽  
R.P Swamy
Keyword(s):  
Experimental Investigation ◽  
Carbon Fibre ◽  
Fatigue Behaviour ◽  
Epoxy Composites ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

Fatigue Behaviour of DLC Coated Al 7075-T6 Alloy in an Aggressive Mixture

2014 ◽  
Vol 627 ◽  
pp. 81-84 ◽  
Author(s):  
Sergio Baragetti ◽  
Riccardo Gerosa ◽  
Francesco Villa
Keyword(s):  
High Performance ◽  
Contact Fatigue ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Structural Elements ◽  
Pvd Coatings ◽  
Bending Fatigue ◽  
Al 7075 ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

7075-T6 aluminium alloy is commonly adopted in high performance structures and components. Its fatigue behaviour is however dramatically worsened by exposure to aggressive environments. The deposition of PVD coatings, which are commonly adopted to increase the surface properties of structural elements in terms of hardness, contact fatigue and wear resistance, could be beneficial also for the fatigue behaviour of a 7075-T6 substrate in an aggressive environment. In the present work, Diamond Like Carbon (DLC) PVD coated 7075-T6 specimens immersed in methanol have been analysed, by means of step-loading rotating bending fatigue tests (R = -1) at 2·105 cycles. Coated specimens were tested in laboratory air for comparison, and uncoated polished samples were studied in both the environments to obtain reference values. SEM micrographs of the fracture surfaces were taken to investigate the effects of the corrosive environment on the failure mechanism.

scholarly journals Influence of Plasma Electrolytic Oxidation on Fatigue Behaviour of ZK60A-T5 Magnesium Alloy

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1180
Author(s):  
Alessandro Morri ◽  
Lorella Ceschini ◽  
Carla Martini ◽  
Alessandro Bernardi
Keyword(s):  
Fatigue Strength ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Fatigue Behaviour ◽  
Powder Coating ◽  
Bending Fatigue ◽  
Electrolytic Oxidation ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Plasma Electrolytic

Magnesium alloys are used in the motorsport and aerospace fields because of their high specific strength. However, due to their low corrosion resistance, protective surface treatments, such as conversion coating or electroless plating, are necessary when they are used in humid or corrosive environments. The present study aimed at evaluating the effect of plasma electrolytic oxidation (PEO), followed by the deposition of a polymeric layer by powder coating, on the rotating bending fatigue behaviour of the wrought magnesium alloy ZK60A-T5. The specimens were extracted from forged wheels of racing motorbikes and were PEO treated and powder coated. Microstructural characterization was carried out by optical (OM) and scanning electron microscopy (SEM) to analyse both the bulk material and the multilayer, consisting of the anodic oxide interlayer with the powder coating top layer (about 40 µm total thickness). Rotating bending fatigue tests were carried out to obtain the S–N curve of PEO-treated specimens. The results of the rotating bending tests evidenced fatigue strength equal to 104 MPa at 106 cycles and 90 MPa at 107 cycles. The results of the investigation pointed out that PEO led to a reduction in fatigue strength between 14% and 17% in comparison to the untreated alloy. Fracture surface analyses of the fatigue specimens, carried out by SEM and by 3D digital microscopy, highlighted multiple crack initiation sites at the interface between the PEO layer and substrate, induced by the concurrent effects of coating defects, local tensile stresses in the substrate, and increased roughness at the substrate–coating interface.

Fatigue behaviour of laser-sintered PA12 specimens under four-point rotating bending

2014 ◽  
Vol 20 (4) ◽  
pp. 291-300 ◽  
Author(s):  
Javier Munguia ◽  
Kenny Dalgarno
Keyword(s):  
Endurance Limit ◽  
Dimensional Accuracy ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Uniaxial Tensile ◽  
Content Type ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Part Orientation

Purpose – The purpose of this paper was twofold: first, to determine if rotating bending could be used as an effective way of determining the fatigue behaviour of laser-sintered nylon, and second, to examine whether the fatigue behaviour of laser-sintered PA12 showed any significant anisotropy. Design/methodology/approach – Specimens were measured to obtain dimensional accuracy, density and surface roughness levels. Then, uniaxial tensile and rotating-bending fatigue tests were performed. A purpose-built test-jig has been used to subject hourglass-shaped specimens to reversed bending at two frequencies: 50 and 30 Hz. Additionally, thermal and microstructural analyses were performed to understand the underlying mechanisms of failure. Findings – The experiments suggest PA12 specimens will fail in fatigue following the conventional fatigue mechanisms observed in previous research with ductile polymers. Although high-frequency loading caused a heat build-up in the specimen, temperatures stabilised between 20 and 30°C, suggesting that rotating-bending fatigue at frequencies of up to 50 Hz is a valid way of determining the fatigue behaviour of laser-sintered PA12 specimens. Stresses below 20 MPa led to fatigue lives above 1 million cycles. Some anisotropic behaviour was observed in the fatigue test results, with specimens made orientated with the Z axis showing the lowest fatigue lives on average, but an endurance limit of approximately 15 MPa seems to be common for all specimens regardless of their build orientation. Practical implications – The observed endurance limit of 15 MPa did not depend significantly on the orientation at which a part was built – meaning that it may be possible to guarantee a service life for a part which does not depend on part orientation within a build. Clearly, good-quality control will also be required to ensure performance, but this has important implications for the design of laser-sintered PA12 parts for realistic service conditions. Originality/value – To our knowledge, this is the first paper to present rotating-bending fatigue data for laser-sintered PA12 parts, and the first to identify an endurance limit which is independent of part orientation.

Effects of PVD DLC Coating on 7075-T6 Fatigue Strength at High and Low Number of Cycles

2016 ◽  
Vol 713 ◽  
pp. 50-53 ◽  
Author(s):  
Sergio Baragetti ◽  
Riccardo Gerosa ◽  
Francesco Villa
Keyword(s):  
Fatigue Strength ◽  
Surface Characteristics ◽  
Fatigue Behaviour ◽  
Bending Fatigue ◽  
Dlc Coating ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Number Of Cycles ◽  
The Impact

Despite its high tensile strength and its brilliant fatigue behaviour, 7075-T6 aluminium alloy usage is dramatically reduced, due to its sensitivity to corrosion and its poor surface characteristics. In order to be adopted for advanced applications in the aeronautic, automotive and maritime fields, as well as in further innovative applications, 7075-T6 resistance must be improved. Controversial results are found in literature on coated 7075-T6 fatigue strength, due to the complex mechanical interaction between the substrate and the coating, and the high temperatures involved in the coating process. In the present work, testing on rotating bending fatigue (R = -1) 7075-T6 uncoated and PVD DLC coated specimens has been conducted. Different stress levels were considered, to assess the impact of the applied stress on the fatigue life of the substrate-coating system. SEM characterization of the fracture surfaces has been performed, to investigate the influence of the coating on the fracture mechanism

On a New Rotating Bending Fatigue Testing Machine

1966 ◽  
Vol 15 (148) ◽  
pp. 49-54
Author(s):  
Minoru KAWAMOTO ◽  
Katsumi SUMIHIRO ◽  
Koji KIDA
Keyword(s):  
Fatigue Testing ◽  
Testing Machine ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

A FAST ROTATING BENDING FATIGUE TEST MACHINE

2017 ◽  
Author(s):  
Marco Antonio Meggiolaro ◽  
Jaime T P Castro ◽  
Rodrigo de Moura Nogueira
Keyword(s):  
Fatigue Test ◽  
Test Machine ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Fast Rotating

A Study onP-S-NCurve for Rotating Bending Fatigue Test for Bearing Steel

2008 ◽  
Vol 51 (2) ◽  
pp. 166-172 ◽  
Author(s):  
Katsuji Tosha ◽  
Daisuke Ueda ◽  
Hirokazu Shimoda ◽  
Shigeo Shimizu
Keyword(s):  
Fatigue Test ◽  
Bearing Steel ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

Application of ANN Back-Propagation for Fracture Design Parameters in Extra-Low Cycle Rotating Bending Fatigue

2009 ◽  
Vol 610-613 ◽  
pp. 450-453
Author(s):  
Hong Yan Duan ◽  
You Tang Li ◽  
Jin Zhang ◽  
Gui Ping He
Keyword(s):  
Neural Network ◽  
Neural Network Model ◽  
Back Propagation ◽  
Training Data ◽  
Design Parameters ◽  
Ann Model ◽  
Bending Fatigue ◽  
The Neural Network ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

The fracture problems of ecomaterial (aluminum alloyed cast iron) under extra-low cycle rotating bending fatigue loading were studied using artificial neural networks (ANN) in this paper. The training data were used in the formation of training set of ANN. The ANN model exhibited excellent in results comparison with the experimental results. It was concluded that predicted fracture design parameters by the trained neural network model seem more reasonable compared to approximate methods. It is possible to claim that, ANN is fairly promising prediction technique if properly used. Training ANN model was introduced at first. And then the Training data for the development of the neural network model was obtained from the experiments. The input parameters, notch depth, the presetting deflection and tip radius of the notch, and the output parameters, the cycle times of fracture were used during the network training. The neural network architecture is designed. The ANN model was developed using back propagation architecture with three layers jump connections, where every layer was connected or linked to every previous layer. The number of hidden neurons was determined according to special formula. The performance of system is summarized at last. In order to facilitate the comparisons of predicted values, the error evaluation and mean relative error are obtained. The result show that the training model has good performance, and the experimental data and predicted data from ANN are in good coherence.

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