Mechanical Properties Of CFRP Research Articles

Numerical investigation on orthogonal cutting and damage response of CFRP/Ti6Al4V stacks

CFRP/Ti6Al4V stacks are widely employed in aerospace, automotive and marine applications owing to their superior properties. However, machining these stacked structures pose challenges due to the intrinsic difference in the mechanical properties of CFRP and Ti6Al4V. Such difference can induce distinct failure mechanisms and chip formation processes compared to those observed in individual materials. This paper presents an explicit finite element (FE) modeling to predict the cutting forces and analyze the induced damage during the orthogonal cutting process. The proposed FE model is validated using available experimental data for separate CFRP and Ti6Al4V conditions before being applied to simulate the cutting behavior of CFRP/Ti6Al4V stacks. The effects of fiber angles, cutting sequences and cutting parameters on the cutting performance and damage mechanism of CFRP/Ti6Al4V stacks are investigated in detail. This work provides insights into the cutting behavior of CFRP/Ti6Al4V stacks and facilitates the optimization of machining process for such composite system.

Fabrication and Formability of Continuous Carbon Fiber Reinforced Resin Matrix Composites Using Additive Manufacturing

In the current process for additive manufacturing of continuous carbon fiber reinforced resin matrix composites, the fiber and resin matrix are fed into the molten chamber, and then impregnated and compounded in the original position, and finally extruded and deposited on the substrate. It is difficult to control the ratio of fiber and resin, and to achieve good interface fusion, which results in an unsatisfactory enhancement effect. Therefore, an additive manufacturing process based on continuous carbon fiber reinforced polylactic acid composite prepreg filament was explored in this study. The effects of various process parameters on the formability of composites were studied through systematic process experiments. The results showed that the process parameters of additive manufacturing have a systematic influence on the forming quality, accuracy and efficiency, and on the mechanical properties of CFRP. Through the experimental optimization of various process parameters, a continuous and stable forming process was achieved when the nozzle aperture was 0.8 mm, the nozzle printing temperature was 240 °C, the substrate temperature was 60 °C, the wire feeding speed was 5 mm/s, the nozzle moving speed was 5 mm/s, the path bonding rate was 40%, and the printing layer thickness was 0.7 mm. Based on the optimized process parameters, direct additive manufacturing of a lightweight and high-strength composite cellular load-bearing structure could be realized. Its volume fraction of carbon fiber was approximately 7.7%, and the tensile strength was up to 224.3 MPa.

Mechanisms and evaluation of the influence of cutting temperature on the damage of CFRP by helical milling

The quality of holes machined in carbon fibre reinforced plastic is vital to the strength of CFRP/Ti stacks. In this study, the influence of cutting temperature upon hole damage of CFRP in CFRP/Ti stacks under helical milling was compared with and without the presence of an underlying Ti. The cutting forces, exit quality, wall surface and subsurface quality of CFRP hole were analysed. And proposing a method to evaluate subsurface damage, and combined with the tensile test to study the effect of subsurface damage on the mechanical properties of CFRP. The results suggest that titanium alloy slightly exerts an effect on the cutting force and exit and wall mass of CFRP holes, yet dramatically affects their subsurface mass. High cutting temperatures may degrade the performance of the CFRP resin matrix, which may cause further subsurface damage closest to the hole exit. The proposed method is used to evaluate subsurface damage. It was most serious in the fibre layer near the hole exit and gradually decreased with distance from the exit. The results of this study will help improve the machining quality of CFRP/Ti stacks.

Evaluation for mechanical properties of CFRP / TPS laminates for the purpose of advanced design of sports equipment

Evaluation for mechanical properties of CFRP / TPS laminates for the purpose of advanced design of sports equipment

인장 시편의 형상을 고려한 탄소섬유보강폴리머의 기계적 특성 분석

사회 기반 시설물들의 노후화가 진행됨에 따라 구조물의 보수 및 보강에 대한 수요가 높아지고 있다. 이러한 구조물의 구조 성능을 향상하기 위하여 경제적이고 효율적인 탄소섬유보강폴리머가 많이 활용되고 있으며, 탄소섬유보강폴리머에 대한 연구가 많이 진행되고 있다. 탄소섬유보강폴리머를 통한 보수 및 보강 효과를 정량적으로 평가하기 위해서는 재료의 기계적 성능을 정량적으로 평가해야한다. ASTM D3039에서 제안하는 표준 시험 방법은 전반적인 평가 방법에 대한 가이드라인을 제시하고 있지만, 구체적인 시편의 형상에 대한 가이드라인을 명확하게 제시하지 않고 있다. 따라서 본 연구에서는 탄소섬유보강폴리머 인장 시편의 형상에 따른 인장성능을 실제 현장에서 사용되는 탄소섬유보강폴리머의 두께를 고려하여 평가하였다.

Optimisation design of CFRP passenger car seat backplane based on impact characteristics

The newly revised GB 13057-2014 put forward high requirements for the dynamic occupant protection of passenger car seats. Due to the high density of steel, there is currently not much space for lightweight through structure improvement. In this paper, the quasi-static and dynamic mechanical properties of CFRP and corresponding simulations are used to study the mechanical behaviour of CFRP and verify the accuracy of simulation. It is now applied to the composite seat backplane structure design, and combined with the CFRP moulding process and the energy absorption characteristics of the car seat backplane to initially design the CFRP seat backplane material and structure. At the same time, considering the designability of the material itself, the ply optimisation technology under multi-condition is used to design the material and structure of the CFRP passenger car seat backplane. The new CFRP passenger car seat achieves significant weight reduction while meeting regulatory requirements.

Improvement of Interfacial Adhesion Strength and MechanicalProperties of CFRP by Fabricated with Modified Matrix byAdding Nano Fibers

Improvement of Interfacial Adhesion Strength and MechanicalProperties of CFRP by Fabricated with Modified Matrix byAdding Nano Fibers

The effect of curvilinear carbon fiber arrangement on the mechanical properties of CFRP manufactured by electro-activated deposition molding

The effect of curvilinear carbon fiber arrangement on the mechanical properties of CFRP manufactured by electro-activated deposition molding

Special Issue on Machining of CFRP Composites

There is a growing need for carbon-fiber-reinforced plastics (CFRP/CFRTP/GFRP) inthe aircraft, aerospace, and automotive industries due to their high strength-to-weightratio, high rigidity, and other features. Using these outstanding composites as machinecomponents requires machining with the desired configuration, accuracy, and surfaceintegrity. However, due to the composite structure of high-strength carbon fiber and theadhesive plastics, CFRP is difficult to machine without causing spalling or delamination,fluffing, fiber pullout, thermal degradation of the matrix resin, or other kinds of surfaceor subsurface damage. Rapid tool wear is also a serious problem that varies with thefiber orientation of the CFRP. In order to avoid these problems, various innovative or careful approaches have beentaken in drilling, trimming by milling, sawing, and grinding CFRP. Non-traditional machiningtechniques, including the use of abrasive waterjets, have been employed. Inthese techniques, the machining process, tool geometry, cooling system, and other machiningparameters are optimized. In addition, the influence of surface integrity on thetensile and/or fatigue strength or on other mechanical properties of CFRP has also drawninterest. In addition, regarded as a “machining process” in a broad sense, the press formingof continuous fiber reinforced thermoplastic (CFRTP) sheets is a promising techniqueused in the manufacture of structural components. In CFRTP forming, the effects thatfiber layout naturally have on the deformation mechanisms must be understood, andtemperature, pressure, speed, and stroke control should be optimized. This special issue consists of twelve recent, high-quality research articles related to themachining of CFRP composite materials. These articles include one review and eleventechnical papers on the topics of drilling, end milling, abrasive waterjet machining, andforming. The editors would like to express our deep appreciation to all the authors fortheir invaluable submissions and to the anonymous reviewers for their earnest efforts.Without these, this special issue could not have been published. We hope that furtherresearch on the machining of CFRP composites will make advances inspired by thisspecial issue.

M704 CFRP(炭素繊維強化複合材料)の機械的特性に及ぼすCNF(セルロースナノファイバ)の添加の効果 : 添加繊維周辺の応力状態のシミュレーションによる検証(GS3 材料力学・計算力学(1),修士研究発表セッション)

M704 CFRP(炭素繊維強化複合材料)の機械的特性に及ぼすCNF(セルロースナノファイバ)の添加の効果 : 添加繊維周辺の応力状態のシミュレーションによる検証(GS3 材料力学・計算力学(1),修士研究発表セッション)

無吸湿熱可塑性樹脂を用いたCFRPの力学的特性評価

無吸湿熱可塑性樹脂を用いたCFRPの力学的特性評価

PS06 熱可塑性微粒子がCFRPの力学的特性に及ぼす影響

PS06 熱可塑性微粒子がCFRPの力学的特性に及ぼす影響

610 アブレイシブウォータージェット加工がCFRPの機械的特性に及ぼす影響

610 アブレイシブウォータージェット加工がCFRPの機械的特性に及ぼす影響

Mechanical Properties and Applications of CFRP in Retrofitting and Repairing Reinforced Concrete Short Columns

The mechanical properties of CFRP without epoxy resin were tested by the monotonic load method, and the corresponding stress-strain relationship curve was established. The probability model and the parameter fitting based on Weibull distribution theory were applied, and the characteristic strength parameter and the shape parameter of CFRP were obtained. Three large scale RC short columns were constructed, the specimen not retrofitted, specimen strengthen retrofitted by CFRP and specimen repaired by CFRP which has been damaged by earthquake were simulated respectively. Quasi-static testing was carried out. The hysteretic-loop curve and average framework curve were obtained, furthermore, the performance of ductility and strength were analyzed and compared. The calculational results approximately agree with the experimental results, which prove the validity of OpenSees. The short columns retrofitted by CFRP have superior ductility so as to enhance the seismic performances effectively. The residual seismic behavior of short columns can also meet the requirement of seismic code. The research provides reference to seismic analysis and engineering design of retrofitted reinforcement concrete structures.

302 家具用木製フレームのCFRPによる補強方法とその機械的性質(機械材料・材料加工)

302 家具用木製フレームのCFRPによる補強方法とその機械的性質(機械材料・材料加工)

609 有機複合材料の残留応力に及ぼす湿熱環境の影響

The effects of moisture and heat on the residual stresses in organic composites are theoretically investigated. From the experimental results, the tensile strength of CFRP cross-ply laminates ([0゜/90゜]_45) at 298k in the high vacuum condition is larger than that in the atmosphere. It is considered that the degas and/or moisture desorption from the matrix of epoxy resin and from the interface occur in the high vacuum condition, and then the mechanical properties of CFRP are changed. On the basis of the theory of diffusion, and coupling of the moisture and the heat with temperature varying the diffusivity, we derived the diffusion equations of the moisture and solved them by the use of the finite deference method. Some numerical calculations for the stresses in the composites are carried out by the use of the finite element method. The stress distribution and the hygrothermal residual stresses in organic composites are shown graphically.

Fibre reinforced composites of multifunctional epoxy resins

AbstractGlass and carbon fibre reinforced epoxy composites were fabricated for N,N,N′,N′‐tetraglycidyl‐4,4′‐diaminodiphenyl methane (TGDDM) and its formulated systems with tri‐ and di‐functional reactive epoxy diluents using 30% diaminodiphenyl sulphone (DDS) as a curing agent. The epoxy laminates were evaluated for their physical, chemical and mechanical properties [at room (26°C) and high (100°C) temperatures]. A marginal increase (<20%) in the mechanical properties of CFRP was found compared with GFRP laminates. Incorporation of epoxy diluents altered the mechanical properties of the composites significantly. The incorporation of triglycidyl‐4‐aminophenol diluent to TGDDM systems resulted in an improvement in mechanical properties of about 2–6%.

カーボン／アラミドハイブリッドＦＲＰ積層板の曲げ特性の材料設計に関する一考察

A material design guideline for the flexural behavior of carbon/aramid hybrid unidirectional FRP laminates (C/A hybrid FRP) was studied from the viewpoint of laminate constitution and time-temperature dependence. As the results, it was found that the flexural behavior under static, impact and cyclic loads changed remarkably with laminate constitution, time or temperature and that the flexural fracture patterns were classified clearly into two modes according to laminate constitution and time-temperature dependence. One is the compressive fracture of the most out CFRP layer in the compression side, and the other is the tensile fracture of the surface AFRP layer in the tension side. Furthermore, the temperature dependent flexural behavior of C/A hybrid FRP predicted by the laminated beam theory using the mechanical properties of CFRP and AFRP agreed approximately with the experimental results mentioned above. Therefore, this proposed deformation and failure criteria are applicable to the material design of C/A hybrid FRP.

The effects of fibre surface coatings on the mechanical properties of CFRP

Some of the methods of absorbing energy in a unidirectional carbon fibre epoxy resin composite are reviewed and an attempt is made to quantify and compare the increases in fracture energy that can be obtained by varying the matrix properties, type of fibre and interlaminar shear strength. It is found that changes in the latter are the most likely to cause a significant increase in fracture energy. One means of decreasing the shear strength in a controlled manner is by coating carbon fibres with small amounts of silicone rubber and curing this prior to making the composite. The effects of the percentage of rubber on the work of fracture and flexural and interlaminar shear strengths are studied and it is found that 1 per cent of silicone rubber leads to an increase of 107 per cent in the work of fracture without a decrease in the flexural strength. It is believed that, for the starting materials used here, this increase in work of fracture is approximately the maximum that can be obtained without a fall off in flexural strength. A simple criterion is proposed to estimate the amount of rubber which can be added before a decrease in flexural strength occurs and a series, Reuss, model is assumed in order to account for the effect of the silicone rubber in decreasing the shear strength. The work of fracture is reasonably successfully accounted for, as a function of the silicone rubber content, in terms of fibre pull out, stress relaxation and debonding mechanisms.