scholarly journals Structural Stress Method to Evaluate Fatigue Properties of Similar and Dissimilar Self-Piercing Riveted Joints

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 359 ◽  
Author(s):  
Harish Rao ◽  
Jidong Kang ◽  
Garret Huff ◽  
Katherine Avery
Keyword(s):  
Fatigue Life ◽  
Analytical Model ◽  
Fiber Reinforced Polymer ◽  
Fatigue Properties ◽  
Structural Stress ◽  
Life Data ◽  
Reinforced Polymer ◽  
Riveted Joints ◽  
Cfrp Composite ◽  
Head Height

In this paper, we discuss the application of a simple Battelle structural stress model to evaluate the fatigue life of a self-piercing riveted (SPR) carbon-fiber-reinforced polymer (CFRP) composite to aluminum AA6111. The analytical model accounts for the forces and moments acting on the rivets to determine the structural stresses which were then plotted against the laboratory-generated fatigue life data. The master S-N curve determined in this study thus accounts for various factors such as the stacking configuration, rivet head height, and fatigue load ratios. The analytical model used in this study was able to collapse a large number of fatigue life data into one master S-N curve irrespective of stack-ups, rivet head height, and load ratios. Thus, the master S-N curve derived from the model can be used to predict the fatigue life of the SPR joints.

Study on the stiffness degradation in concrete continuous beam with externally prestressed CFRP tendons under fatigue loading

2021 ◽  
pp. 136943322199249
Author(s):  
Xing Li ◽  
Jiwen Zhang ◽  
Jun Cheng
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Fiber Reinforced Polymer ◽  
Stiffness Degradation ◽  
Test Results ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Practical Engineering ◽  
Good Agreement

This paper presents fatigue behaviors and the stiffness degradation law of concrete continuous beams with external prestressed carbon fiber-reinforced polymer (CFRP) tendons. Three specimens were tested under fatigue loading, and the influence of different load levels on the stiffness degradation and fatigue life were studied, and it was found that the stiffness degradation of three test specimens exhibited a three-stage change rule, namely rapid decrease, stable degradation, and sharp decline, but there are obvious differences in the rate and amplitude of stiffness degradation. The load level has a significant influence on the fatigue life of the test specimens. An analytical model with load level considered was proposed to calculate the residual stiffness and predict the stiffness degradation, which is in good agreement with the test results. The model of stiffness degradation presents a possible solution for practical engineering applications of concrete continuous beams with externally prestressed CFRP tendons subjected to different fatigue loadings.

scholarly journals Influence of the Arrangement of Mechanical Fasteners on the Static Strength and Fatigue Life of Hybrid Joints

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5308
Author(s):  
Marek Rośkowicz ◽  
Jan Godzimirski ◽  
Andrzej Komorek ◽  
Jarosław Gąsior ◽  
Michał Jasztal
Keyword(s):  
Fatigue Life ◽  
Negative Impact ◽  
Complex Problem ◽  
Static Strength ◽  
Fiber Reinforced Polymer ◽  
Mechanical Joints ◽  
Reinforced Polymer ◽  
Hybrid Joints ◽  
Stage Process ◽  
And Performance

This paper presents the results of experimental research and numerical calculations regarding the static strength and fatigue life of hybrid joints. In the experiments, specimens built as single-lap adhesive–mechanical joints (hybrid joints) were tested. In a two-stage process of the failure of the hybrid joints, the adhesive joint was damaged first. Therefore, it was assumed that the assembly of fasteners closer to the edge of the overlap (beyond the ranges recommended for mechanical joints) limits the negative impact of the peeling phenomenon on the strength and performance properties of hybrid joints. The specimens used in the experiments were prepared from composite elements (i.e., carbon fiber-reinforced polymer (CFRP)), as well as from the aluminum alloy 2024T4. Because the detection of fatigue damage in composite materials is a complex problem, computed tomography was used to evaluate the degradation of the composite material. Experimental and numerical comparative analyses of the static strength and fatigue life of hybrid joints with adhesive and mechanical joints confirmed the assumptions made.

Fatigue Testing Method of Test Coupon and Structurally Equivalent Samples of Carbon Fiber Reinforced Polymer for Gas Turbine Engine Parts and Assemblies

2018 ◽  
Vol 284 ◽  
pp. 43-47
Author(s):  
M.S. Nikhamkin ◽  
N.A. Sazhenkov ◽  
D. Samodurov
Keyword(s):  
Carbon Fiber ◽  
Gas Turbine ◽  
Polymer Composite ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fatigue Properties ◽  
Fiber Reinforced ◽  
Test Coupon ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The carbon fiber reinforced polymer composite are widely used in industry as major structural materials. They represent the greatest interest for the production of gas turbine engines parts because of their high specific strength. But before adaptation these materials into the structure, it is necessary to conduct a number of tests, both on test coupon and on structurally equivalent samples for determining physical, in particular, fatigue properties of these materials. However, the high cost of manufacturing coupons for such tests has a negative impact on the adaptation of carbon fiber reinforced polymer composite into the composition of final products. In this paper it is presented a method for fatigue tests of test coupon and structurally equivalent samples of carbon fiber reinforced polymer, aimed at reducing the consumption of coupons which are necessary for obtaining fatigue properties. Based on the developed method, a series of carbon fiber coupons was tested and the fatigue limit was obtained. At the same time, the use of coupons was minimized.

Novel Mathematical-Statistical Models for the Distribution of Fatigue Life and Residual Strength for Fiber Reinforced Polymer Composites

2020 ◽  
Vol 12 (09) ◽  
pp. 2050104
Author(s):  
Jiqiang Hu ◽  
Chunming Ji ◽  
Shuai Chen ◽  
Shuai Li ◽  
Bing Wang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Polymer Composites ◽  
Residual Strength ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Distribution Models ◽  
Degradation Model ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Curve Model

For the distribution prediction of fatigue life and residual strength of fiber reinforced polymer composites, the existing models have the disadvantages of imprecision, instability and single applicability. A novel S–N curve model and a residual strength degradation model were first developed, which are independent and uncorrelated. After verifying their reliability, the statistical distribution models of fatigue life and residual strength were further derived and verified by using experimental data from literature. Compared with the other models, the proposed models can perfectly predict the probability distribution of fatigue life and residual strength under different materials, stacking sequences and stress levels, showing excellent prediction accuracy, stability and applicability.

The Finite Element Research of Fatigue Properties of Steel Q345 Butt Welded Joint

2014 ◽  
Vol 670-671 ◽  
pp. 1087-1090
Author(s):  
Wei Ping Ouyang ◽  
Liang Sheng Chen ◽  
Xiu Dong Xu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Life ◽  
Stress Distribution ◽  
Welded Joint ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Structural Stress ◽  
Design Development ◽  
Stress Theory

The research of fatigue properties of the butt welded joint, though a large number of fatigue tests are need to be carried out, has significant influence to hoisting equipment’s design, development and using safety. This paper conducted a study on simulating the fatigue properties of widely used steel Q345 butt welded joint’s by finite element method based on the improved linear equivalent structural stress theory. The originally massive amount of fatigue tests and data processing could be saved. In order to ensure the accuracy of the fatigue modeling, a batch of Q345 butt welded joints were prepared for the fatigue tests which is used to contrast with the modeling result. The stress distribution under different load situation and the fatigue life of the joints, which have profound reference significance to hoisting machinery industry, can be acquired through modeling.

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