scholarly journals Measurement and Analysis of Residual Stresses and Warpage in Fiber Reinforced Plastic and Hybrid Components

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 335
Author(s):  
Tao Wu ◽  
Steffen Tinkloh ◽  
Thomas Tröster ◽  
Wolfgang Zinn ◽  
Thomas Niendorf
Keyword(s):  
Residual Stresses ◽  
Process Parameters ◽  
Composite Structures ◽  
Mechanical Performance ◽  
Orthotropic Materials ◽  
Hole Drilling ◽  
Drilling Process ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic

Glass/carbon fiber reinforced plastic (GFRP/CFRP) and hybrid components have attracted increasing attention in lightweight applications. However, residual stresses induced in the manufacturing process of these components can result in warpage and, eventually, negatively affect the mechanical performance of the composite structures. In the present work, GFRP, CFRP, GFRP/steel and CFRP/steel hybrid components were manufactured through the prepreg-press-technology always employing the same process parameters. The residual stresses of these components were measured through the hole drilling method (HDM), based on an adequate formalism to evaluate the residual stresses for orthotropic materials including the calculation of the calibration coefficients via finite element analysis (FEA). In FEA, the real material lay-up and mechanical properties of the samples were considered. The warpage induced by residual stresses was measured after the samples were removed from the tool. The measured residual stresses and warpage of four different types of samples were compared and results were analyzed in depth. The results obtained can be extended to other hybrid materials and even could be used for designing multi-stable laminates for application in adaptive structures. Moreover, the effects of the drilling process parameters of HDM, e.g., the drilling speed, the drilling increment and the zero-depth setting, on the resulting residual stresses of GFRP were investigated. The reliability of residual stress measurements in GFRP using HDM was validated through mechanical bending tests. The conclusions concerning the choice of optimal drilling parameters for GFRP could be directly applied for other types of samples considered in the present work.

Face Milling of Carbon Fiber Reinforced Plastic Using Poly Crystalline Diamond Tool

2014 ◽  
Vol 1017 ◽  
pp. 383-388 ◽  
Author(s):  
Jumpei Kusuyama ◽  
Akinori Yui ◽  
Takayuki Kitajima ◽  
Yosuke Itoh
Keyword(s):  
Carbon Fiber ◽  
High Strength ◽  
Face Milling ◽  
Hole Drilling ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced ◽  
Poly Crystalline Diamond

Carbon Fiber Reinforced Plastic (CFRP) is a high-strength and high-elastic-modulus composite material that is hardened by impregning carbon fiber with epoxy resin. Although, many sutdies of hole drilling of CFRP have been conducted, few sutdies of face milling of CFRP have been carried out. Face milling is necessary for surfaceing of aerospace parts, which is indispensable for airplane construction. Machining of CFRP is difficult because of the extreme tool wear and delamination that occur. The authors investigated face milling of CFRP using a newly developed Poly Crystalline Diamond (PCD) tool. The resultts show, that the cutting force and surface roughness are affected by the fiber orientation of the CFRP, and that delamination can easily occur in the outer layer of face-nilled CFRP.

scholarly journals Study on Mechanical Bearing Strength and Failure Modes of Composite Materials for Marine Structures

2021 ◽  
Vol 9 (7) ◽  
pp. 726
Author(s):  
Dong-Uk Kim ◽  
Hyoung-Seock Seo ◽  
Ho-Yun Jang
Keyword(s):  
Composite Materials ◽  
Failure Mode ◽  
Composite Structures ◽  
Failure Modes ◽  
Offshore Structures ◽  
Fiber Reinforced ◽  
Bearing Strength ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Mechanically Fastened

With the gradual application of composite materials to ships and offshore structures, the structural strength of composites that can replace steel should be explored. In this study, the mechanical bearing strength and failure modes of a composite-to-metal joining structure connected by mechanically fastened joints were experimentally analyzed. The effects of the fiber tensile strength and stress concentration on the static bearing strength and failure modes of the composite structures were investigated. For the experiment, quasi-isotropic [45°/0°/–45°/90°]2S carbon fiber-reinforced plastic (CFRP) and glass fiber-reinforced plastic (GFRP) specimens were prepared with hole diameters of 5, 6, 8, and 10 mm. The experimental results showed that the average static bearing strength of the CFRP specimen was 30% or higher than that of the GFRP specimen. In terms of the failure mode of the mechanically fastened joint, a cleavage failure mode was observed in the GFRP specimen for hole diameters of 5 mm and 6 mm, whereas a net-tension failure mode was observed for hole diameters of 8 mm and 10 mm. Bearing failure occurred in the CFRP specimens.

scholarly journals Investigation of mechanical characteristics of braided carbon fiber

2021 ◽  
pp. 13-22
Author(s):  
Mykhailo Bohatyr ◽  
Gennadiy Lvov ◽  
Oleksii Vodka ◽  
Oleksandr Oleksandrovych Chepeliuk
Keyword(s):  
Composite Materials ◽  
Carbon Fiber ◽  
Composite Structures ◽  
Natural Frequencies ◽  
Carbon Fiber Reinforced Plastic ◽  
Damping Properties ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Modes Of Vibration

The use of composite materials in various branches of modern industry is rapidly increasing due to their high strength properties, low weight and good manufacturability. A wide variety of materials used, types of reinforcement and internal structures creates a need for studies of the static and dynamic properties of composite materials. Due to the latest advances in technology, composite materials are widely used in a variety of industrial applications. As a result, there is considerable interest in studying and understanding the behavior of composite structures. Analysis of composite structures, study of resonance frequencies, damping factors and modal shapes played an important role in determining the dynamic characteristics of the structure, detecting damage and monitoring the state of the composite structure. In this paper, the results of computational and experimental researches of the Young’s modulus, natural frequencies and modes of vibration, damping properties of the composite material are presented. The researches were carried out on samples of the woven ten-layer carbon fiber reinforced plastic. The investigated carbon fiber reinforced plastic has a plain weave. Samples were cut in three directions: warp (0 °), weft (90 °) and 45 °. Nine samples were prepared for each direction. To study the Young’s modulus, a tensile testing machine was used, and a vibration stand was used to determine the natural frequencies and modes of vibration. Damping properties are calculated by the Oberst method, based on the amplitude-frequency characteristics of the samples. Statistical processing of the experimental results was carried out and the values ​​of the mathematical expectation and variance were obtained. Geometric and finite element models of сarbon fiber reinforced plastic samples were built, their natural frequencies and vibration modes were determined. Comparison of the computational and experimental data with numerous calculations using the finite element method is carried out.

FKV-Bohrrohre mit strukturintegrierter Sensorik/Vibration damping and process monitoring in BTA deep hole drilling using fiber composites – FRP drill tubes with structure-integrated sensors

2021 ◽  
Vol 111 (11-12) ◽  
pp. 846-850
Author(s):  
Sebastian Michel ◽  
Dirk Biermann ◽  
Moritz Kurkowski ◽  
Axel Spickenheuer ◽  
Markus Stommel ◽  
...  
Keyword(s):  
Fiber Composites ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Fiber Reinforced Plastic ◽  
Damping Behavior ◽  
Reinforced Plastic ◽  
Process Reliability ◽  
Steel Drill

Bei BTA-Tiefbohrprozessen kommt es aufgrund der großen Werkzeuglängen häufig zu Torsionsschwingungen des Werkzeugsystems aus Bohrkopf und Bohrrohr. Im Vergleich zu konventionellen Stahl-Bohrrohren reduzieren Bohrrohre aus faserverstärktem Kunststoff diese Schwingungen durch ihr materialspezifisches Dämpfungspotenzial und erhöhen damit die Prozesssicherheit und verringern den Werkzeugverschleiß. Die Einbindung von Sensorfasern direkt in das Laminat erlaubt zudem eine Prozessüberwachung.   In BTA deep hole drilling, torsional vibrations of the tool system consisting of a drill head and a drill tube often occur due to the long tool lengths. Compared to conventional steel drill tubes, drill tubes made of fiber-reinforced plastic reduce these vibrations through their material-specific damping behavior and thus increase the process reliability and reduce the tool wear. The integration of sensor fibers directly into the laminate also allows a monitoring of the drilling process.

Physical and mechanical performance of an innovative glass-fiber-reinforced plastic rod for concrete and grouted anchorages

1993 ◽  
Vol 20 (2) ◽  
pp. 254-268 ◽  
Author(s):  
O. Chaallal ◽  
B. Benmokrane
Keyword(s):  
Thermal Expansion ◽  
Glass Fiber ◽  
Mechanical Performance ◽  
Strength Development ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Plastic ◽  
Fiber Reinforced Plastic ◽  
Glass Fiber Reinforced ◽  
Reinforced Plastic ◽  
Steel Rebars

Recently, consideration has been given to replacing conventional steel rebars with glass-fiber-reinforced plastic rods in specific applications such as structures subjected to corrosive or marine environment or where electrical or electro magnetic insulation is required. The paper presents the results of a laboratory investigation including physical and mechanical behaviour of a glass-fiber-reinforced plastic rod. The following tests were conducted: thermal expansion, tension at ambient and high temperatures, compression, flexure, shear, fatigue on bare rods, and pullout of rods embedded in concrete. It was found that the glass-fiber-reinforced plastic rod possessed a higher ultimate tensile stress but much lower modulus of elasticity than steel rebars. The plastic rods withstood fewer cycles than steel bars, particularly at higher levels of stress. The loss of strength at temperatures above 200 °C was found to be considerably higher than steel. The coefficient of longitudinal thermal expansion was similar to that of concrete and steel. In light of the results, examples for concrete structural elements have been illustrated in the paper. Key words: glass-fiber rod, plastic, reinforced concrete, thermal expansion, tension, compression, flexure, shear, high temperature, fatigue, pullout, bond strength, development length, beams, slabs, median barriers.

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