Investigation of Fatigue Life and Residual Strength of Wing Panel for Reliability Purposes

2009 ◽  
pp. 75-75-31 ◽  
Author(s):  
S Eggwertz
Keyword(s):  
Fatigue Life ◽  
Residual Strength ◽  
Wing Panel

scholarly journals Fatigue performance of nanoclay filled glass fiber reinforced hybrid composite laminate

2017 ◽  
Author(s):  
◽  
John Olumide Olusanya
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Glass Fiber ◽  
Residual Strength ◽  
Composite Structures ◽  
Fatigue Performance ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Glass Fiber Reinforced

In this study, the fatigue life of fiber reinforced composite (FRC) materials system was investigated. A nano-filler was used to increase the service life of the composite structures under cyclical loading since such structures require improved structural integrity and longer service life. Behaviour of glass fiber reinforced composite (GFRC) enhanced with various weight percentages (1 to 5 wt. %) of Cloisite 30B montmorillonite (MMT) clay was studied under static and fatigue loading. Epoxy clay nanocomposite (ECN) and hybrid nanoclay/GFRC laminates were characterised using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The mechanical properties of neat GFRC and hybrid nanoclay/GFRC laminates were evaluated. Fatigue study of the composite laminates was conducted and presented using the following parameter; matrix crack initiation and propagation, interfacial debonding, delamination and S–N relationship. Residual strength of the materials was evaluated using DMA to determine the reliability of the hybrid nanoclay/GFRC laminates. The results showed that ECN and hybrid nanoclay/GFRC laminates exhibited substantial improvement in most tests when compared to composite without nanoclay. The toughening mechanism of the nanoclay in the GFRC up to 3 wt. % gave 17%, 24% and 56% improvement in tensile, flexural and impact properties respectively. In the fatigue performance, less crack propagations was found in the hybrid nanoclay/GFRC laminates. Fatigue life of hybrid nanoclay/GFRC laminate was increased by 625% at the nanoclay addition up to 3 wt. % when compared to neat GFRC laminate. The residual strength of the composite materials revealed that hybrid nanoclay/GFRC showed less storage modulus reduction after fatigue. Likewise, a positive shift toward the right was found in the tan delta glass transition temperature (Tg) of 3 wt. % nanoclay/GFRC laminate after fatigue. It was concluded that the application of nanoclay in the GFRC improved the performance of the material. The hybrid nanoclay/GFRC material can therefore be recommended mechanically and thermally for longer usage in structural application.

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.

Calculating Fatigue Life of Helicopter Composite Blades Based on the Residual Strength Theory

2014 ◽  
Vol 941-944 ◽  
pp. 1552-1557
Author(s):  
Wei Wang ◽  
Yu Lin Zhu ◽  
Qi Min Xiao
Keyword(s):  
Fatigue Life ◽  
Failure Probability ◽  
Residual Strength ◽  
Treatment Plan ◽  
Flight Time ◽  
Load Spectrum ◽  
Strength Theory ◽  
Composite Blade ◽  
Stress Spectrum ◽  
Calculation Results

This paper presents a method for calculating the fatigue life of helicopter composite material blade with residual strength theory. Builded the residual strength model, analyzed the influence of loading sequence, tensile -- compressed between the conversion and failure probability, adopt corresponding treatment plan. Using the model of residual strength, selected 19 typical flight condition, using the "rain flow counting method" load matrix, finally get the helicopter load spectrum. The composite blade dangerous section are calculated (root maximum strain), combined with every moment and centrifugal force, the flight state determined blade the stress spectrum, then according to the blade model and material characteristic parameters were calculated, results show that the residual strength decreases with the increase of flight time, and the failure probability increased with the flight time increasing. By comparison, the calculation results and full size is consistent with the experimental results, which shows the calculation is reliable.

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