Effects of resin pre-coating on interfacial bond strength and toughness of laminar CFRP with and without short aramid fibre toughening

2020 ◽  
Vol 54 (25) ◽  
pp. 3883-3893
Author(s):  
Binhua Wang ◽  
Guangzhi Ding ◽  
Gang Wang ◽  
Sisi Kang
Keyword(s):  
Carbon Fiber ◽  
Adhesive Layer ◽  
Aramid Fibre ◽  
Mode I ◽  
Test Results ◽  
Interfacial Bond Strength ◽  
Treatment Technology ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Aramid Fibres

The brittle adhesive layer in carbon fiber-reinforced polymer (CFRP) laminates was strengthened by using short aramid fibers in this study. To ensure the feasibility and effectiveness of short aramid fiber interfacial toughening at the interface between the carbon-fiber face sheets, the self-prepared short aramid fibre tissue and the wettability treatment technology with resin pre-coating were applied to enable short aramid fibres to be well embedded in the uneven regions in the CFRP fabrics with fibres oriented at 0° and 90° to form a strong pulling resistance. The ultimate load and the mode I interlaminar fracture toughness have been improved by 75% and 103.9% from the double cantilever beam mode I crack propagation tests, respectively. The reinforcing mechanisms within the “composite adhesive layer” as a result of short aramid fibres are discussed together with detailed scanning electron microscopy observations and comparison test results.

Defects Study on Drilling of Carbon Fiber Reinforced Polymer (CFRP) Laminates

2014 ◽  
Vol 800-801 ◽  
pp. 61-65 ◽  
Author(s):  
Kun Xian Qiu ◽  
Cheng Dong Wang ◽  
Qing Long An ◽  
Ming Chen
Keyword(s):  
Carbon Fiber ◽  
Feed Rate ◽  
High Speed ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Cfrp Laminates ◽  
Drilling Performance ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The new developed carbon fiber reinforced polymer laminates are widely used in main structural components of big commercial aircrafts. Generally drilling is the final operations in manufacturing structure, which is the most important operation during assembly. Defects such as burrs and delamination always appear in the process of drilling, which makes it hard to control the drilling quality. In this research, the drilling defects of T800 CFRP laminates are evaluated by using a brad point drill and a multifacet drill in terms of drilling forces, burr defect and delamination detection. The results show that the spindle speed is the most significant factor affecting the delamination defect followed by the feed rate. High speed drilling and low feed rate could improve the surface quality and reduce the delamination. The multifacet drill showed excellent drilling performance than the brad point drill and generated smaller defects.

Grouted anchorages for aramid fibre reinforced plastic prestressing tendons

1993 ◽  
Vol 20 (6) ◽  
pp. 1065-1069 ◽  
Author(s):  
K. S. McKay ◽  
M. A. Erki
Keyword(s):  
Prestressed Concrete ◽  
Steel Tube ◽  
High Ratio ◽  
Aramid Fibre ◽  
Test Results ◽  
Structural Deterioration ◽  
Reinforced Composite ◽  
Reinforced Plastic ◽  
Aramid Fibres ◽  
Lateral Strength

Nonmetallic prestressing tendons, made of fibre-reinforced composite materials, are being proposed as alternatives to steel prestressing tendons for bridges and parking garage structures, where corrosion is the leading cause of structural deterioration. One type of commercially available nonmetallic tendons is made of pultruded aramid fibres. One of the main problems for these tendons, which is common to all nonmetallic tendons, is that the high ratio of the axial to lateral strength of fibre-reinforced materials requires special attention to the type of anchorage used. For the aramid tendon, the simplest grouted anchorage consists of a steel tube filled with nonshrink grout, into which the end of the tendon is embedded. This note presents the test results of a parametric study on grouted anchorages for pultruded aramid tendons. Key words: prestressed concrete, nonmetallic tendons, aramid fibre, grouted anchorage.

scholarly journals Strengthening of Reinforced Concrete Slab-Column Connections with Carbon Fiber Reinforced Polymer Laminates

2019 ◽  
Vol 10 (1) ◽  
pp. 265 ◽  
Author(s):  
Cheng-Chih Chen ◽  
Shun-Long Chen
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Concrete Slab ◽  
Fiber Reinforced Polymer ◽  
Punching Shear ◽  
Carbon Fiber Reinforced Polymer ◽  
Cfrp Laminates ◽  
Reinforced Polymer

This study presents the structural behavior and punching shear strength of the concrete slab-column connections strengthened with carbon fiber reinforced polymer (CFRP) laminates. The variables considered for the twelve specimens included the compressive strength of the concrete, the ratio of the tensile steel reinforcement, and the amount of the CFRP laminates. Square concrete slabs were simply supported along four edges. During the test, monotonically concentrated load was applied to the stub column located at the center of the slab. The punching shear strength, stiffness, and mode of failure were investigated. Test results demonstrated that increasing the compressive strength of concrete, ratio of the steel reinforcement, and amount of the CFRP laminates led to an increase in the punching shear strength of the slabs. Moreover, the CFRP laminates were effective in appreciably increasing the punching shear strength of the slab-column connections. An analytical approach was conducted to calculate the punching shear strength of the slab-column connections strengthened with CFRP laminates. Based on the theory of reinforced concrete members, the application of the CFRP laminates increased the flexural strength of the slab and resulted in an increase of the effective depth of the slab section. Consequently, the punching shear strength was increased. The results of the analytical calculation revealed that the analytical work accurately predicted the experimental punching shear strength.

scholarly journals Characteristics of Eddy Current Distribution in Carbon Fiber Reinforced Polymer

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Shaoni Jiao ◽  
Jian Li ◽  
Fei Du ◽  
Lei Sun ◽  
Zhiwei Zeng
Keyword(s):  
Carbon Fiber ◽  
Eddy Current ◽  
Fiber Reinforced Polymer ◽  
Electrical Anisotropy ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Direction ◽  
Fiber Reinforced ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The paper studies the characteristics of eddy current (EC) distribution in carbon fiber reinforced polymer (CFRP) laminates so as to guide the research and operation of eddy current testing of CFRP. To this end, an electromagnetic field computation model of EC response to CFRP based on the finite element method is developed. Quantitative analysis of EC distribution in plies of unidirectional CFRP reveals that EC changes slowly along the fiber direction due to the strong electrical anisotropy of the material. Variation of EC in plies of multidirectional CFRP is fast in both directions. The attenuation of EC in the normal direction in unidirectional CFRP is faster than that in isotropic material due to faster diffusion of EC. In multidirectional CFRP, EC increases near the interfaces of plies having different fiber orientations. The simulation results are beneficial to optimizing sensor design and testing parameters, as well as damage detection and evaluation.

scholarly journals Strain Transfer Characteristic of a Fiber Bragg Grating Sensor Bonded to the Surface of Carbon Fiber Reinforced Polymer Laminates

2018 ◽  
Vol 8 (7) ◽  
pp. 1171
Author(s):  
Zhongyu Wang ◽  
Hongyang Li ◽  
Li Zhang ◽  
Jingfeng Xue
Keyword(s):  
Carbon Fiber ◽  
Strain Measurement ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Transfer Model ◽  
Strain Transfer ◽  
Cfrp Laminates ◽  
Reinforced Polymer ◽  
Host Materials ◽  
Fbg Sensors

Structural health monitoring is of great importance for the application of composites in aircrafts. Fiber Bragg grating (FBG) sensors are very suitable for structure strain measurement. However, the strain measured by FBG sensors is different from the original strain in host materials. The relationship between them is defined as strain transfer. As composites are anisotropic, the traditional strain transfer model, which regards the elasticity modulus of host materials as a constant, is inadaptable. In this paper, a new strain transfer model is proposed for FBG sensors bonded to the surface of carbon fiber reinforced polymer (CFRP) laminates. Based on the measurement structure, the model is established and the transfer function is derived. The characteristics influencing the strain transfer are analyzed. The stacking directions, stacking numbers, and stacking sequences of CFRP laminates have a distinct effect on the transfer efficiency, which is different from the isotropy host materials. The accuracy of the proposed model was verified by experiments on a nondestructive tensile system, and the maximum model error is less than 0.5%. Moreover, the model was applied to the strain measurement of CFRP wing skin, which indicates that measurement errors decrease by 11.6% to 19.8% after the compensation according to the model.

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