scholarly journals Interlaminar Shear Behavior of Laminated Carbon Fiber Reinforced Plastic from Microscale Strain Distributions Measured by Sampling Moiré Technique

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1684 ◽  
Author(s):  
Qinghua Wang ◽  
Shien Ri ◽  
Hiroshi Tsuda ◽  
Yosuke Takashita ◽  
Ryuta Kitamura ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Shear Strain ◽  
Shear Behavior ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced ◽  
Interlaminar Shear

In this article, the interlaminar shear behavior of a [±45°]4s laminated carbon fiber reinforced plastic (CFRP) specimen is investigated, by utilizing microscale strain mapping in a wide field of view. A three-point bending device is developed under a laser scanning microscope, and the full-field strain distributions, including normal, shear and principal strains on the cross section of CFRP, in a three-point bending test, are measured using a developed sampling Moiré technique. The microscale shear strain concentrations at interfaces between each two adjacent layers were successfully detected and found to be positive-negative alternately distributed before damage occurrence. The 45° layers slipped to the right relative to the −45° layers, visualized from the revised Moiré phases, and shear strain distributions of the angle-ply CFRP under different loads. The absolute values of the shear strain at interfaces gradually rose with the increase of the bending load, and the sudden decrease of the shear strain peak value implied the occurrence of interlaminar damage. The evolution of the shear strain concentrations is useful in the quantitative evaluation of the potential interlaminar shear failure.

scholarly journals Interlaminar Shear Behavior of Laminated Carbon Fiber Reinforced Plastic from Microscale Strain Distributions Measured by Sampling Moire Technique

2018 ◽  
Author(s):  
Qinghua Wang ◽  
Shien RI ◽  
Hiroshi Tsuda ◽  
Yosuke Takashita ◽  
Ryuta Kitamura ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Shear Strain ◽  
Shear Behavior ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Three Point Bending ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced ◽  
Interlaminar Shear

The interlaminar shear behavior of a [±45°] laminated carbon fiber reinforced plastic (CFRP) specimen was investigated utilizing microscale strain mapping in a wide field of view. A three-point bending device was developed under a laser scanning microscope, and the full-field strain distributions including normal, shear and principal strains of CFRP in a three-point bending test were measured using a developed sampling Moire technique. The microscale shear strain concentrations at interfaces between each two adjacent layers were successfully detected and found to be positive-negative alternately distributed before damage occurrence. The 45° layers slipped to the right relative to the -45° layers, visualized from the revised Moire phases and shear strain distributions of the angle-ply CFRP under different loads. The absolute values of the shear strain at interfaces gradually rose with the increase of the bending load, and the sudden decrease of the shear strain peak value implied the occurrence of interlaminar damage. The evolution of the shear strain concentrations is useful in the quantitative evaluation of the potential interlaminar shear failure.

Failure modes and failure mechanisms of single tooth bound to composite pre-tightened tooth connection

2017 ◽  
Vol 37 (4) ◽  
pp. 267-283 ◽  
Author(s):  
Yifeng Gao ◽  
Fei Li ◽  
Qilin Zhao ◽  
Jiangang Gao ◽  
Xiaoqiang Yan ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Failure Modes ◽  
Failure Mechanisms ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Plastic ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced ◽  
Interlaminar Shear

To assess the failure modes and failure mechanisms of single pre-tightened tooth connection joints, experiments were conducted on the mechanical properties of three different materials―T700/DER-321, T700/EP4221, and E-glass/HCH-8300―under different geometric parameters. During the test, failure processes and details of the fracture surfaces were observed by using a high-speed camera, an optical microscope, and a scanning electron microscope. Then, the failure modes and failure mechanisms of the joints were analyzed by numerical simulation and theoretical methods. The results showed that only two failure modes, shear failure and crushing failure, occurred in the glass fiber-reinforced plastic single joint. However, in addition to these two failure modes, a new failure mode was found to occur in the carbon fiber-reinforced plastic single joint, i.e. compression failure. The glass fiber-reinforced plastic joint had a lower elastic modulus along the fiber direction than the carbon fiber-reinforced plastic joint, which was the fundamental cause for the new failure mode. The carbon fiber-reinforced plastic joint with compression failure had a higher bearing capacity, and a certain ductile failure will occur as a result of the large interlaminar shear strength of the composite, which is an important consideration in joint design. Thus, the material type, the geometrical parameters of the tooth, and the interlaminar shear strength of the composite all influenced the failure modes and the bearing capacity of single pre-tightened tooth connection joints.

scholarly journals Stressing State Analysis of Reinforced Concrete Beam Strengthened by CFRP Sheet with Anchoring Device

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 576
Author(s):  
Liang Luo ◽  
Jie Lai ◽  
Jun Shi ◽  
Guorui Sun ◽  
Jie Huang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Strain Distribution ◽  
Carbon Fiber Reinforced Plastic ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Strain Distribution Pattern ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Cfrp Sheet ◽  
Carbon Fiber Reinforced

This paper investigates the working performance of reinforcement concrete (RC) beams strengthened by Carbon-Fiber-Reinforced Plastic (CFRP) with different anchoring under bending moment, based on the structural stressing state theory. The measured strain values of concrete and Carbon-Fiber-Reinforced Plastic (CFRP) sheet are modeled as generalized strain energy density (GSED), to characterize the RC beams’ stressing state. Then the Mann–Kendall (M–K) criterion is applied to distinguish the characteristic loads of structural stressing state from the curve, updating the definition of structural failure load. In addition, for tested specimens with middle anchorage and end anchorage, the torsion applied on the anchoring device and the deformation width of anchoring device are respectively set parameters to analyze their effects on the reinforcement performance of CFRP sheet through comparing the strain distribution pattern of CFRP. Finally, in order to further explore the strain distribution of the cross-section and analyze the stressing-state characteristics of the RC beam, the numerical shape function (NSF) method is proposed to reasonably expand the limited strain data. The research results provide a new angle of view to conduct structural analysis and a reference to the improvement of reinforcement effect of CFRP.

Study on the mechanism of inhomogeneous microdamage in short-pulse laser processing of carbon fiber reinforced plastic

2021 ◽  
pp. 073168442098359
Author(s):  
Luyao Xu ◽  
Jiuru Lu ◽  
Kangmei Li ◽  
Jun Hu
Keyword(s):  
Carbon Fiber ◽  
Pulse Energy ◽  
Short Pulse ◽  
Heterogeneous Material ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Processing Efficiency ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced

In this article, a micro-heterogeneous material simulation model with carbon fiber and resin phase about laser ablation on carbon fiber reinforced plastic (CFRP) is established by Ansys. The ablation process of CFRP by nanosecond ultraviolet laser is simulated, and the mechanism of pulse energy and spot spacing on the heat-affected zone (HAZ) is studied, then the process parameters are optimized with the goal of HAZ size and processing efficiency, and finally the validity of the model is verified by experiments. It is found that the residual gradient and the width of the radial HAZ increase with the increase of the spot spacing, and the width of the axial HAZ decreases slightly with the increase of the spot spacing, which indicates the existence of the optimal spot spacing. Second, the ablation depth increases with the increase of the pulse energy, and the carbon fiber retains a relatively complete degree of exposure when the pulse energy is low, which has a certain guiding significance for the cleaning and bonding of CFRP.

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