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.

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.

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.

scholarly journals Performance of Reinforced Concrete Slab with Opening Strengthened Using CFRP

Fibers ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 25
Author(s):  
Syafiqah Shahrul Aman ◽  
Bashar S. Mohammed ◽  
Mubarak Abdul Wahab ◽  
Abdullah Anwar
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Fiber Reinforced Polymer ◽  
Sufficient Information ◽  
Reinforced Concrete Slab ◽  
Reinforced Polymer ◽  
Load Carrying ◽  
Cfrp Sheet ◽  
And Performance ◽  
Rc Slabs

Openings in reinforced concrete (RC) slabs are not commonly prescribed in design codes. Even when they are, they raise concerns regards to the size of the openings and the location of the applied loads. Lack of sufficient information about the load-carrying capacity of the slabs with openings and performance is another concern. Hence, this research addresses the structural behavior of slabs with openings coated with Carbon Fiber Reinforced Polymer (CFRP) sheet. In the experimental part, ten slabs were cast with a dimension of 1000 mm × 530 mm × 25 mm, among which nine slabs had openings and one slab was without opening (control slab). The configuration of the CFRP sheet includes coating in the form of single, double, and triple layers. Experimental results show that the slab with a triple coating of the CFRP layer offers the maximum resistance towards the loading rate. Moreover, with the increase in CFRP layers, the value of deflection is minimized.

Impact of efficiency and practicality of CFRP anchor installation techniques on the performance of RC beams strengthened with CFRP sheets

2019 ◽  
Vol 46 (9) ◽  
pp. 796-809 ◽  
Author(s):  
Mohammed A. Zaki ◽  
Hayder A. Rasheed
Keyword(s):  
Reinforced Concrete ◽  
Real World ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Application Time ◽  
Flexural Capacity ◽  
Cfrp Sheets ◽  
Reinforced Polymer ◽  
Real World Applications ◽  
And Performance

Utilizing fiber reinforced polymer (FRP) anchors can enhance the strength and delay the debonding of flexural FRP in strengthened reinforced concrete (RC) beams. In this study, two different techniques are used for applying carbon FRP (CFRP) spike anchors to improve the performance of RC beams strengthened with CFRP sheets. These two techniques are compared with respect to the ease of application, time spent, size of installation team, and performance. The first technique involved applying the CFRP anchors to begin with, then installing CFRP sheets by separating the fibers at the location of anchors. The second technique applied the CFRP sheets first to the beam soffit right after drilling the holes. This was followed by inserting CFRP anchors through the sheets into the prepared holes. The conclusion indicates that the second technique is easier, faster, and more practical in real-world applications. In addition, the use of distributed CFRP anchors increased the flexural capacity of the strengthened beams.

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