Sensitivity Study of Probit and Two-Point Fatigue Testing Methods

2006 ◽  
Author(s):  
Jiangtao Song ◽  
Paul N. Crepeau ◽  
Randy J. Gu ◽  
Zissimos P. Mourelatos
Keyword(s):  
Fatigue Testing ◽  
Sensitivity Study ◽  
Testing Methods

scholarly journals Fatigue Stress-Life Model of RC Beams Based on an Accelerated Fatigue Method

2019 ◽  
Vol 4 (2) ◽  
pp. 16
Author(s):  
Eljufout ◽  
Toutanji ◽  
Al-Qaralleh
Keyword(s):  
Cyclic Loading ◽  
Fatigue Testing ◽  
Three Dimensional ◽  
Rc Beam ◽  
Rc Beams ◽  
Testing Methods ◽  
Load Range ◽  
Fatigue Stress ◽  
Life Model ◽  
Prediction Band

Several standard fatigue testing methods are used to determine the fatigue stress-life prediction model (S-N curve) and the endurance limit of Reinforced Concrete (RC) beams, including the application of constant cyclic tension-tension loads at different stress or strain ranges. The standard fatigue testing methods are time-consuming and expensive to perform, as a large number of specimens is needed to obtain valid results. The purpose of this paper is to examine a fatigue stress-life predication model of RC beams that are developed with an accelerated fatigue approach. This approach is based on the hypothesis of linear accumulative damage of the Palmgren–Miner rule, whereby the applied cyclic load range is linearly increased with respect to the number of cycles until the specimen fails. A three-dimensional RC beam was modeled and validated using ANSYS software. Numerical simulations were performed for the RC beam under linearly increased cyclic loading with different initial loading conditions. A fatigue stress-life model was developed that was based on the analyzed data of three specimens. The accelerated fatigue approach has a higher rate of damage accumulations than the standard testing approach. All of the analyzed specimens failed due to an unstable cracking of concrete. The developed fatigue stress-life model fits the upper 95% prediction band of RC beams that were tested under constant amplitude cyclic loading.

Effect of Loading on Stress Intensification Factors

2005 ◽  
Vol 128 (1) ◽  
pp. 33-38
Author(s):  
Rudolph J. Scavuzzo
Keyword(s):  
Fatigue Life ◽  
Evaluation Method ◽  
Fatigue Testing ◽  
Plastic Material ◽  
Strain Curve ◽  
Correct Prediction ◽  
Piping System ◽  
Testing Methods ◽  
Strain Cycle ◽  
Perfectly Plastic

The basic objective of this investigation is to determine the effect of loading on the stress intensification factors of Markl’s fatigue evaluation method for metal piping. Markl’s method is based on the fatigue testing of 4 in. schedule 40 carbon steel cantilever piping. Subsequent testing using a four-point loading showed that the S-N data were different from that predicted by the procedure and equation developed by Markl. Markl’s method is based on determining the elastic-plastic forces in a piping system by multiplying the elastic system stiffness by the actual deflection. In this manner a fictitious force is calculated to determine piping stresses assuming the elastic beam bending equation, Mc/I, applies even in partially plastic pipes. Previous analytical work on this topic by Rodabaugh and Scavuzzo (“Fatigue of Butt Welded Pipe and the Effect of Testing Methods–Report 2: Effect of Testing Methods on Stress Intensification Factors,” Welding Research Bulletin 433, July 1998) showed that these measured differences should occur between cantilever and four-point tests using Markl’s method. The basic assumption in this analytical comparison is that strain-cycle correlations lead to the correct prediction of fatigue life. Using the measured alternating strain, both types of test geometries lead to the same prediction of fatigue life using these strain-cycle correlations. In this study, the same analytical assumptions used by Rodabaugh and Scavuzzo (above) are applied to a pipe where the load is varied from a four-point loading through its extremes. Loads were varied from a cantilever to an end moment by changing the dimensions of four-point loading. Also, the shape of a bilinear stress-strain curve was varied from a perfectly plastic material to various degrees of work hardening by increasing the tangent modulus in the plastic regime. The results of the study indicate that Markl’s method is conservative by predicting too short a fatigue life for four-point loading for a given stress. As indicated by this study, the differences can be very large in the low-cycle regime for a perfectly plastic material and for a four-point loading approaching an end moment. Thus, piping could be over designed with unnecessary conservatism using the current ASME Code method based on stress intensification factors.

Laboratory Testing of Prosthetic Heart Valves

1987 ◽  
Vol 16 (2) ◽  
pp. 67-76 ◽  
Author(s):  
H Reul ◽  
M Giersiepen ◽  
E Knott
Keyword(s):  
Steady Flow ◽  
Pulsatile Flow ◽  
Laboratory Testing ◽  
Heart Valves ◽  
Fatigue Testing ◽  
Comparative Test ◽  
Prosthetic Heart Valves ◽  
Test Results ◽  
Testing Methods

A whole range of laboratory testing methods for prosthetic heart valves, such as steady flow testing, pulsatile flow testing, and fatigue testing, are presented. Comparative test results for various valve types are given and relative valve performance is discussed.

scholarly journals Fatigue Testing Methods for Elastomer

2010 ◽  
Vol 83 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Katsuhiko TSUNODA
Keyword(s):  
Fatigue Testing ◽  
Testing Methods

scholarly journals Analysis of Torque Maintenance and Fracture Resistance after Fatigue in Retention Screws Made of Different Metals for Screw-Retained Implant-Borne Prosthesis Joints

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Maria Beatriz Bello Taborda ◽  
Gabriela Sumie Yaguinuma Gonçalves ◽  
Cecília Alves de Sousa ◽  
Wirley Gonçalves Assunção
Keyword(s):  
Fracture Resistance ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Compression Testing ◽  
Testing Methods ◽  
Mechanical Cycling ◽  
Universal Testing ◽  
Grade 5 ◽  
Alloy Material ◽  
Connection Type

Purpose. The aim was to evaluate the effect of different metallic alloys used in the manufacture of retention screws for universal cast to long abutment (UCLA) abutments for external hexagon (HE) and Morse taper (MT) connection implants, as well as of mechanical cycling on torque maintenance and fracture resistance through electromechanical fatigue testing by mastication followed by compression testing. Methods. Sixty implants were used, 30 MT and 30 HE, with their respective titanium UCLA abutments and retention screws of 5 different materials (n = 6): Ti cp grade 2, Ti cp grade 4, Ti cp grade 4 hard, Ti grade 5—Ti6Al4V and surgical steel (DSP® Biomedical). The assemblies were positioned in an electromechanical masticatory fatigue testing machine. The fracture strength test was performed by compression testing in a universal testing machine EMICDL-200. Results. The cycled screws and new screws of each alloy group for each connection type were evaluated, obtaining the maximum force (FM), in order to verify the effect of mechanical cycling. The data were tabulated and submitted to appropriate statistical analysis (α = 0.05). Conclusion. It was concluded that for the MT, the alloy with the best performance was steel, both in the maintenance of torque and in the compression test, and cycling negatively influenced the maintenance of preload for this connection. The alloy material did not influence torque maintenance for HE. The new screws that were subjected to EMIC showed higher strength. The alloy with the lowest strength was Ti grade 2.

scholarly journals VHCF Properties of A7075-T651 Al Alloy Depending on Shot Peening and Fatigue Testing Methods

2014 ◽  
Vol 7 (1) ◽  
pp. 126848 ◽  
Author(s):  
Min-Soo Suh ◽  
Chang Hee Suh ◽  
Seung-Hoon Nahm ◽  
Chang-Min Suh
Keyword(s):  
Shot Peening ◽  
Fatigue Testing ◽  
Al Alloy ◽  
Testing Methods

Thermomechanical Fatigue: Testing Methods and Application

2001 ◽  
Author(s):  
César Augusto De Jesus Falcão ◽  
Waldek Wladimir Bose Filho ◽  
Dirceu Spinelli
Keyword(s):  
Fatigue Testing ◽  
Thermomechanical Fatigue ◽  
Testing Methods

Study on Development and Testing Mechanism of a New Multifunction Agricultural V-Belt Fatigue Testing Machine

2014 ◽  
Vol 527 ◽  
pp. 185-189
Author(s):  
Wei Feng Zhang ◽  
Fu Xia Zhang ◽  
Ying Jie Lv ◽  
Feng Feng Bao
Keyword(s):  
Basic Principle ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Service Condition ◽  
Structural Features ◽  
Testing Equipment ◽  
Fatigue Performance ◽  
Agricultural Machinery ◽  
Testing Methods ◽  
Loading Mode

Agricultural V-belt fatigue testing machine is a kind of testing equipment developed based on the service condition of the agricultural V-belt, for the detection of fatigue performance of agricultural V-belt. The paper firstly analyzes the transmission principle, loading mode and testing parameters of the agricultural V-belt fatigue testing machine, and then introduces its basic principle, detection parameters and the main structural features, based on which the fatigue performance of the agricultural V-belt is tested and perfectly checked by the testing result. The study is to improve the testing equipment and testing methods for testing the fatigue performance of our national agricultural V-belt, to enhance the overall testing ability in China's agricultural machinery industry and to guide the production and use of agricultural V-belts.

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