scholarly journals Evaluation of Energy-Based Model Generated Strain Signals for Carbon Steel Spring Fatigue Life Assessment

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 213 ◽  
Author(s):  
Yat Kong ◽  
Shahrum Abdullah ◽  
Dieter Schramm ◽  
Mohd Omar ◽  
Sallehuddin Mohamed Haris
Keyword(s):  
Fatigue Life ◽  
Elastic Strain Energy ◽  
Vertical Displacement ◽  
Life Assessment ◽  
Coefficient Of Determination ◽  
Coil Spring ◽  
Acceleration Data ◽  
Time Histories ◽  
Fatigue Life Analysis ◽  
Life Predictions

This paper presents the evaluation of the automobile coil-spring strain-displacement relationship for strain signals generation and fatigue life predictions. The development of a strain and spring vertical displacement relationship is significant because measuring vehicle wheel displacements and forces are complex and costly. Hence, there is a need to estimate the strain data using alternative measurement, such as vibration signals. In this analysis, strain and acceleration data were collected from a vehicle that has travelled on different road conditions. Through the material elastic strain energy and spring potential energy relationship, a coil-spring parameterise strain-displacement relationship has been developed and evaluated using a scatter band and correlation approach. Using this proposed model, the strain time histories were obtained based on acceleration data. For fatigue life analysis, most of the predicted fatigue life was distributed in the acceptable range using the scatter band approach where the data correlated at coefficient of determination value (R2) of 0.8788. With a suitable correlation value, this analysis proposed an alternative strain generation method for suspension coil spring fatigue life prediction, which could significantly shorten the spring development time.

Fatigue Life Analysis of an Automotive Tensioner Through Strain-Life Approach

2015 ◽  
Author(s):  
Maryam Talimi ◽  
Jean W. Zu
Keyword(s):  
Fatigue Life ◽  
Stress Analysis ◽  
Drive System ◽  
Life Assessment ◽  
Fatigue Properties ◽  
Fatigue Life Assessment ◽  
Front End ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Prediction Approach

In this paper, fatigue life assessment of a tensioner is studied through dynamic load analysis, stress analysis, and stress-life fatigue analysis approach. Tensioner is a critical part of an automotive front end accessory drive system, providing pre-tension to the belt. The front end accessory drive systems are responsible for transmitting power from the crankshaft to the accessory components. Due to the engine pulsation, components of the accessory drive including the tensioner are subjected to dynamic loads leading to fatigue failure. The fatigue life assessment of a mechanical component highly depends on loading, geometry, and material properties. In addition, the dynamic behavior of the front end accessory drive is complicated due to coupling between several modes of vibrations in belt, pulleys, and the tensioner arm. Duo to the complexity of the parameters involved and complicated dynamics, the fatigue life analysis of FEAD components is a challenging task. This paper includes three main parts, namely stress analysis, fatigue properties prediction, and life estimation. The dynamic analysis of a generic front end accessory drive system is performed in order to obtain effective loads on the tensioner. Stress state for the tensioner in case of different applied loading conditions is performed via a series of Finite Element (FE) analyses, and the critical region of the part is determined. Finally, fatigue life is estimated through strain-life approach. Modest work has been found in this area providing a comprehensive solution to the fatigue life investigation of power train components. The present study offers a comprehensive modeling approach which predicts the automative tensioner lifetime. The lifetime of any FEAD system components can be determined using the developed fatigue life prediction approach.

Fatigue Life Analysis of Solder Joints in Flip Chip Bonding

1999 ◽  
Vol 122 (3) ◽  
pp. 207-213 ◽  
Author(s):  
Yutaka Tsukada ◽  
Hideo Nishimura ◽  
Masao Sakane ◽  
Masateru Ohnami
Keyword(s):  
Fatigue Life ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Electrical Potential ◽  
Potential Drop ◽  
Life Assessment ◽  
Circuit Board ◽  
Ratchet Effect ◽  
The Difference ◽  
Fatigue Life Analysis

This paper describes the life assessment of flip chip joints. Flip chip joints of 63Sn-37Pb and 5Sn-95Pb solders on a printed circuit board were stressed thermally for fatigue. Fatigue lives of the joints were determined by an electrical potential drop method and the effect of encapsulation on fatigue life was discussed. The encapsulation had a significant effect of prolonging the fatigue life of the joints. Thermo-mechanical finite element analyses proved that the encapsulation lowered the strain amplitude of the joints by distributing the strain over a whole package and bending effect. Cracking location was also discussed in relation with the strain concentration in the joints. Fatigue lives of the flip chip joints were compared with those of bulk round bar specimens and the difference in fatigue life between two types of specimens was discussed from the specimen dimensions and ratchet effect. [S1043-7398(00)00203-6]

Research on Fatigue Life Assessment of Fiber Glass Reinforced Flexible Pipe

2019 ◽  
Author(s):  
Yong Bai ◽  
Jiannan Zhao ◽  
Xinyu Sun ◽  
Xiaojie Zhang ◽  
Zhao Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Fatigue Life ◽  
Bending Moment ◽  
Life Assessment ◽  
Fiber Glass ◽  
Flexible Pipe ◽  
Flow Method ◽  
Finite Element Software ◽  
Time Histories

Abstract Fiber glass reinforced flexible pipe (FGRFP) is a kind of submarine pipe widely used in oil and gas transportation and exploration. This paper mainly studies the theoretical and numerical simulation methods for calculating the fatigue life of the FGRFP. Firstly, the tension time-histories and bending moment time-histories of the FGRFP are obtained by using global analysis. The tension and bending moment frequency distribution histograms are obtained by using rain flow method. Then, the finite element software ABAQUS is used to build the model of the FGRFP, and the corresponding tension and bending moment are applied on the finite element model. Then, the stress time histories curve of the FGRFP is obtained. By comparing the results of numerical simulation, the main factors affecting the fatigue life of the FGRFP are studied. Finally, according to rain flow method, S-N curve and numerical simulation results, the fatigue life and single damage rate of FGRFP are obtained.

Fatigue Life Analysis of Polyurethane Bending Stiffeners

2005 ◽  
Author(s):  
Fre´de´ric Demanze ◽  
Didier Hanonge ◽  
Alain Chalumeau ◽  
Olivier Leclerc
Keyword(s):  
Fatigue Life ◽  
Effective Strain ◽  
Fatigue Behaviour ◽  
Life Assessment ◽  
Test Results ◽  
Critical Areas ◽  
Fatigue Life Assessment ◽  
Fatigue Data ◽  
Life Analysis ◽  
Fatigue Life Analysis

Following some experiences of bending stiffeners fatigue failures during full scale tests performed at Flexi France on flexible pipe and stiffener assemblies, Technip decided to launch in 1999 a major research program on fatigue life analysis of bending stiffeners made of Polyurethane material. This fatigue life assessment is now systematically performed by Technip for all new design of flexible riser bending stiffeners. This totally innovative method comprises a number of features as follows: Firstly fatigue behaviour of polyurethane material is described. The theoretical background, based on effective strain intensity factor, is detailed, together with experimental results on laboratory notched samples, solicited under strain control for various strain ratios, to obtain fatigue data. These fatigue data are well fitted by a power law defining the total number of cycles at break as a function of the effective strain intensity factor. The notion of fatigue threshold, below which no propagation is observed, is also demonstrated. Secondly the design used by Technip for its bending stiffeners, and most of all the critical areas regarding fatigue for these massive polyurethane structures are presented. Thirdly the methodology for fatigue life assessment of bending stiffeners in the critical areas defined above is discussed. Calibration of the strain calculation principle is presented versus finite element analysis. Based on all fatigue test results, the size of the equivalent notch to be considered at design stage, in the same critical areas, is discussed. Finally, a comprehensive calibration of the methodology according to full and middle scale test results is presented. The present paper is therefore a step forward in the knowledge of fatigue behaviour of massive polyurethane bending stiffener structures, which are critical items for flexible risers integrity, and widely used in the offshore industry. The confidence in bending stiffeners reliability is greatly enhanced by the introduction of this innovative methodology developed by Technip.

Fatigue Life Analysis of Al 8090 Helicopter Fuselage Panels

2007 ◽  
Vol 348-349 ◽  
pp. 637-640
Author(s):  
Marco Giglio ◽  
Andrea Manes ◽  
Massimo Fossati
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
High Stress ◽  
Experimental Tests ◽  
Life Assessment ◽  
Fatigue Crack Growth Resistance ◽  
Anisotropic Mechanical Properties ◽  
High Crack ◽  
Life Analysis ◽  
Fatigue Life Analysis

Considering the aerospace structures, the advantages of Al-Li alloys in comparison with conventional aluminium alloys comprise relatively low densities, high elastic modulus, excellent fatigue and toughness properties, and superior fatigue crack growth resistance. Unfortunately, these alloys have some disadvantages due to highly anisotropic mechanical properties and due to a very high crack growth rate for microstructurally short cracks. This could mean relatively early cracking in high stress regions such as rivet holes in helicopter fuselage panels. Consequently a more accurate approach in fatigue life analysis is requested. Considering that the 8090 T81 aluminium alloy has been widely used in an helicopter structure, in particular in the bolted connection between the stringers and the modular joint frame in the rear of the fuselage, it is extremely important to found a reliable procedure for the fatigue life assessment of the component. Thus, using the results of experimental tests made on panel specimens, a FE general model and two submodels of the critical zone (involved in fatigue damage during the tests) have been modelled in order to investigate the complex state of stress near the rivets holes. These stress values obtained have been elaborated for a fatigue assessment.

Fatigue Life Assessments of the SAE 5160 Carbon Steel Subjected to Uphill and Downhill Roads Strains

2020 ◽  
Vol 402 ◽  
pp. 33-38
Author(s):  
Teuku Edisah Putra ◽  
Husaini ◽  
Hary Prakasa ◽  
Iskandar Hasanuddin ◽  
Muhammad Rizal ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Carbon Steel ◽  
Strain Gauge ◽  
Life Assessment ◽  
Coil Spring ◽  
Fatigue Life Assessment ◽  
Cycles To Failure

This study examines the fatigue life of the SAE 5160 carbon steel as the material for an automotive coil spring subjected to road strain. The strain signals were acquired by attaching a strain gauge on the component, driving a car up- and down-hill roads. The results of the fatigue life assessment based on the strain-life approach show that the downhill road resulted in a lifespan of 15,000 cycles to failure, which was 53% lower than the uphill road. This value was a result of braking when the vehicle is moving downhill, causing stress to the component leading to shorter fatigue life.

scholarly journals Design, service and testing grounds stress spectra and their using to fatigue life assessment of bus bodyworks

2018 ◽  
Vol 165 ◽  
pp. 17007 ◽  
Author(s):  
Miloslav Kepka ◽  
Miloslav Kepka
Keyword(s):  
Fatigue Life ◽  
The Body ◽  
Life Assessment ◽  
Time Data ◽  
Design Spectrum ◽  
Mechanical Parts ◽  
Operating Modes ◽  
Fatigue Life Assessment ◽  
Time Histories ◽  
Critical Sections

In the development of a road vehicle such as a bus, the input data for the assessment of the fatigue life of the body and other mechanical parts of the vehicle are gradually refined. In the initial phase of the development of a new vehicle, so-called design stress spectra are used. It is necessary to estimate the design spectrum parameters correctly. At the vehicle's prototype testing phase, the so-called service stress spectra can be evaluated. It is essential to determine the characteristic operating modes of the vehicle and to record representative stress-time histories of the critical sections of the construction nodes and vehicle components. Accelerated driving test of fatigue life can be performed on special test routes. The acceleration of such a fatigue test is dependent on the test track composition. The paper generally describes the methodology of such a process and demonstrates it using unique real-time data acquired during the development of a bus.

scholarly journals Characterizing Spring Durability for Automotive Ride Using Artificial Neural Network Analysis

2018 ◽  
Vol 7 (3.17) ◽  
pp. 47
Author(s):  
Y S. Kong ◽  
S Abdullah ◽  
D Schramm ◽  
M Z. Omar ◽  
S M. Haris ◽  
...  
Keyword(s):  
Neural Network ◽  
Mathematical Model ◽  
Fatigue Life ◽  
Design Process ◽  
Vertical Vibration ◽  
Coil Spring ◽  
Acceleration Time ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Automotive Suspension

This paper presents the establishment of a relationship between coil spring fatigue life and automotive vertical vibration using neural network. During an automotive suspension design process, the suspension components are designed with the consideration of structure strength and fatigue life as well as the effects toward automotive ride. Hence, it is important to have a functional mathematical model to predict the fatigue life and automotive life simultaneously. To build the mathematical model, a multibody kinematic quarter model of suspension system was constructed to simulate force and acceleration time histories from the suspension system and the sprung mass of the vehicle model. The force time histories were used to predict the fatigue life of the coil spring while the acceleration time histories were converted into ISO vertical vibration index. A neural network model was created and used to fit the spring fatigue life and vehicle vertical vibration into a mathematical function. The neural network with 1 hidden layer and 2 neurons has shown a good fitting of the data with coefficient of determination as high as 0.88, 0.98, 0.96 for training, validation and testing, respectively. This constructed neural network serves to predict the vehicle vertical vibration using the spring fatigue life and suspension natural frequencies as input, and hence reduce the automotive suspension design process.    

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