scholarly journals Surrogate Model Based Analysis of Inter-Ply Shear Stress in Fiber Reinforced Thermoplastic Composite Sheet Press Forming

2020 ◽  
Vol 10 (16) ◽  
pp. 5499
Author(s):  
Abera Tullu ◽  
Bong-Sul Lee ◽  
Ho-Yon Hwang
Keyword(s):  
Shear Stress ◽  
Surrogate Model ◽  
Orientation Angle ◽  
Computer Experiments ◽  
Thermoplastic Composite ◽  
Fiber Reinforced ◽  
Reinforced Composite ◽  
Press Forming ◽  
Forming Parameters ◽  
Fiber Orientation Angle

The anisotropic nature of fiber reinforced composite materials causes great challenges in predicting the inter-ply shear stress during forming. The complexity of understanding the functional dependency of inter-ply shear stress on multiple forming parameters such as blank temperature, pressure load, inter-ply slippage, and the relative fiber orientation angle of adjacent plies further limits the effort to produce a defect-free composite structure. Performing real experiments for various combinations of the mentioned parameters is both time consuming and economically costly. To overcome these difficulties, a surrogate-based analysis of inter-ply shear stress is proposed in this study. Based on the ranges of the forming parameters, computer experiments were performed. Using these experimental data, a radial basis function (RBF) based surrogate model that mimics inter-ply shear stress during composite press forming was developed. The fidelity of this model was checked with test data and found to be over 98% efficient.

Numerical Simulation of the Orthogonal Cutting of Carbon Fiber Reinforced Composite Material

2014 ◽  
Vol 887-888 ◽  
pp. 1246-1250 ◽  
Author(s):  
Zhi Kai Li ◽  
Dong Lu ◽  
Qiang Wang ◽  
Yong Bo Wu
Keyword(s):  
Carbon Fiber ◽  
Fiber Orientation ◽  
Orthogonal Cutting ◽  
Orientation Angle ◽  
Surface Damage ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Fiber Orientation Angle ◽  
Carbon Fiber Reinforced

This work is focused on the study of orthogonal cutting of carbon fiber reinforced composite. A model based on finite element was developed. Through defining ultimate stresses of fiber tension cracking and fiber compression bucking, ultimate stresses of matrix longitudinal tensile and shear damage. Cutting forces obtained from the FE simulation matches well with the experimental observations. Than analysis cracking and crushing phenomenon of matrix in different fiber orientation, the influence of fiber orientation on sub-surface damage was studied, it shows that the cracking of sub-surface damage value increased with the increase of fiber orientation angle.

Accuracy of Intersection Counting Method in Measurement of Fiber Orientation Angle Distribution Using Image Processing

2006 ◽  
Vol 324-325 ◽  
pp. 415-418
Author(s):  
Jin Woo Kim ◽  
Dong Gi Lee
Keyword(s):  
Image Processing ◽  
Fiber Orientation ◽  
Orientation Angle ◽  
Angle Distribution ◽  
Counting Method ◽  
Fiber Aspect Ratio ◽  
Reinforced Composite ◽  
Orientation Function ◽  
Orientation State ◽  
Fiber Orientation Angle

While mold fiber reinforced composite material to problem of occasion that high temperature compression molding, flow length in mold is overlong or when flow meets with resistance in side of mold, fiber orientation happens and big change occurs in strength or quality. Thus, in compression molding that use fiber reinforced composite material, orientation state of fiber in moldings is the most basic element that quotes various properties of matter values. Therefore, to clear orientation state of fiber establishing measurement of fiber orientation angle distribution is very important while give correction of molding condition decision, mechanical quality of moldings and guide about material design. In the study, the fiber orientation distribution of simulation figure plotted by PC is measured using image processing in order to examine the accuracy of intersection counting method. The fiber orientation function measured by intersection counting method using image processing is compared with the calculated fiber orientation function. The results show that the measured value of fiber orientation function using intersection counting method is lower than the calculated value, because the number of intersection between the scanning line and the fiber with smaller fiber aspect ratio is counted less than with larger fiber aspect ratio.

scholarly journals Fiber Reinforced Composite Based Functionally Gradient Materials

1998 ◽  
Vol 7 (4) ◽  
pp. 096369359800700 ◽  
Author(s):  
VK Ganesh ◽  
S Ramakrishna ◽  
HJ Leck
Keyword(s):  
Mechanical Properties ◽  
Fiber Orientation ◽  
Orientation Angle ◽  
Gradient Material ◽  
Material System ◽  
Test Results ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Functionally Gradient

A method of fabricating fiber-reinforced composite based functionally gradient material is described in this paper. The material has continuously varying mechanical properties along the length. The continuous variation of the mechanical properties is achieved by continuously varying the fiber orientation using the braiding process. The test results indicate an elastic modulus increase by about 42% from the largest braid angle to the smallest braid angle for the material system and the orientation angle considered in the present study.

scholarly journals Discrete Element Analysis of the Strength Anisotropy of Fiber-Reinforced Sands Subjected to Direct Shear Load

2020 ◽  
Vol 10 (11) ◽  
pp. 3693
Author(s):  
Linxian Gong ◽  
Lei Nie ◽  
Yan Xu
Keyword(s):  
Fiber Orientation ◽  
Tensile Force ◽  
Orientation Angle ◽  
Discrete Element ◽  
Soil Reinforcement ◽  
Direct Shear ◽  
Strength Anisotropy ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Fiber Orientation Angle

Soil reinforcement with natural or synthetic fibers enhances its mechanical behavior in various applications. Fiber-reinforced sands (FRS) can be relatively anisotropic because of the fiber self-weight and the compaction technique. However, the microscopic mechanisms underlying the anisotropy are still poorly understood. This study used a discrete element approach to analyze the microscopic mechanisms underlying the strength anisotropy of FRS due to fiber orientation. Analysis of contact networks revealed that the optimum fiber orientation angle is perpendicular to the main direction of strong contact force in direct shear testing. These fibers produced the largest increase in shear zone thickness, normal force around the fiber body, effective contact area, tensile force along fibers, and energy storage/dissipation. This study is valuable for further understanding of the mechanical behaviors of FRS.

Thermal characteristics of unidirectional carbon fiber reinforced polymer laminates during orthogonal cutting

2018 ◽  
Vol 37 (13) ◽  
pp. 905-916 ◽  
Author(s):  
Qinglong An ◽  
Jie Chen ◽  
Xiaojiang Cai ◽  
Tingting Peng ◽  
Ming Chen
Keyword(s):  
Carbon Fiber ◽  
Fiber Orientation ◽  
Cutting Temperature ◽  
Orientation Angle ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Orientation Angle ◽  
Carbon Fiber Reinforced

Carbon fiber reinforced polymer has been used as a major material for primary load-bearing structural components in aviation industry. But its poor heat resistance is an important factor affecting the machining performance, because high cutting temperature above glass transition temperature of resin matrix (normally 300°C or below) may lead to the degradation of the resin matrix. In this study, orthogonal machining experiments were conducted to investigate the effects of cutting parameters, cutting tool geometric parameters, and material parameters on cutting temperature, and the prediction model of cutting temperature about fiber orientation angle ( θ) was built. Cutting temperature was measured by semiartificial thermocouple method. The experimental results revealed that the influence of cutting parameters on cutting temperature was not affected by fiber orientation angle of carbon fiber reinforced polymer. Cutting tool geometric parameters have little effect on cutting temperature. Unlike metal materials, cutting temperature was greatly influenced by θ. Cutting temperature for θ < 90° was significantly higher than that for θ > 90°. The maximum temperature occurred at θ = 90°. The influence of fiber orientation angle was shown in two aspects: changing the springback of unidirectional-carbon fiber reinforced polymer laminates in cutting process, changing material removal mechanism, which affected cutting temperature eventually.

scholarly journals On the origin of start-up effects in ply-ply friction for UD fiber-reinforced thermoplastics in melt

2021 ◽  
Author(s):  
Rens Pierik ◽  
Wouter Grouve ◽  
Sebastiaan Wijskamp ◽  
Remko Akkerman
Keyword(s):  
Shear Stress ◽  
Yield Stress ◽  
Nonlinear Viscoelasticity ◽  
Wall Slip ◽  
Simulation Software ◽  
Design Stage ◽  
Fiber Reinforced ◽  
Press Forming ◽  
Start Up ◽  
Long Time

Hot press forming is an attractive production technology to fulfil the increasing demand for complex fiber-reinforced thermoplastic parts. Over the years, process simulation tools on press forming have shown to be very helpful in facilitating the design stage for defect free parts production. One of the important deformation mechanisms considered in process simulations is the relative slip of successive plies or ply-ply friction, of which the underlying principles need to be better understood in order to improve the overall predictive simulation quality. In particular the use of steady-state friction values, neglecting the transient response, is questionable as experiments showed that shear stress overshoots can be as high as three times the long-time value. The phenomenon of the overshoot at start-up shear is analyzed. Possible explanations include nonlinear viscoelasticity and a slip relaxation effect giving rise to wall slip, which are discussed using relevant ply-ply friction measurements carried out on a dedicated friction test set-up. Experimental results on UD C/PEEK show that the shear stress build up and subsequent relaxation comply with nonlinear viscoelasticity. However, the long-time shear stress fails to match the matrix material’s viscosity, possibly due to a yield stress. The flow curve corrected for a yield stress resembles the effects of wall slip. A transient model according to these findings will enhance the accuracy of press forming simulation software.

A Study on the Tensile Strength and Thermal Property of CFRP Using Infrared Thermography Camera

2014 ◽  
Vol 1016 ◽  
pp. 140-144
Author(s):  
Hee Jae Shin ◽  
In Pyo Cha ◽  
Min Sang Lee ◽  
Tae Ho Kim ◽  
Hyun Kyung Yun ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
Thermal Imaging ◽  
Fiber Orientation ◽  
Thermal Characteristics ◽  
Orientation Angle ◽  
Maximum Temperature ◽  
Reinforced Composite ◽  
Imaging Camera ◽  
Fiber Orientation Angle

The fiber is considered the most important element in fiber reinforced composite materials, as it generally occupies the largest volume in a composite material; further, delivers the heaviest loads. therefore, it is important to select types, quantity and proper stacking angles of the fiber. In this study, the fiber directions were arranged in different orientation angles, i.e. in symmetric (0°/0°,15°/15°,30°/30°,45°/45°,90°/90°) and asymmetric (0°/15°,0°/30°,0°/45°,0°/90°), to analyze the tensile strengths depending on the fiber orientation angles through the tensile test. In addition, a thermal imaging camera was used to investigate the thermal characteristics of the test specimens generated during the tensile test. the tensile strength showed a tendency of decreasing while the orientation angle increased. the maximum temperature generated when the fracture occurred increased at the fiber orientation angle of 30°, and showed a tendency of decreasing as the orientation angle increased.

Thermoplastic Stress Analysis of Graphite Reinforced Composite Cantilever Beam of Arbitrary Orientation, Subjected to Uniformly Distributed Loads

2000 ◽  
Author(s):  
Fuat Okumus ◽  
Aydin Turgut ◽  
Erol Sancaktar
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Composite Beam ◽  
Stress Component ◽  
Orientation Angle ◽  
Thermoplastic Composite ◽  
Reinforced Composite ◽  
Stress Components ◽  
Uniformly Distributed Loads ◽  
Thermoplastic Stress

Abstract In this study, an elastic-plastic stress analysis is performed in a carbon fiber reinforced thermoplastic composite beam, which is loaded uniformly at the upper surface. An analytical solution is obtained including both the governing differential equations and boundary conditions. The composite beam is loaded uniformly at the upper surface, therefore the normal stress component σy is neglected in comparison with other stress components. The orientation angle of the composite is changed as 0°, 15°, 30° and 45°. The intensity of the residual stress component of σx is maximum at the upper and lower surfaces of the composite beam. The intensity of the residual stress component of the shear stress τxy is maximum around the central axis for the beam.

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