An Inelastic Constitutive Equation of Fiber Reinforced Plastic Laminates

1998 ◽  
Vol 120 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Y. Kanagawa ◽  
S. Murakami ◽  
T. Mizobe
Keyword(s):  
Inelastic Deformation ◽  
Evolution Equations ◽  
Kinematic Hardening ◽  
Strain Tensor ◽  
Equivalent Strain ◽  
Time Dependent ◽  
Inelastic Behavior ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Reinforced Plastic

A Constitutive model for describing the time dependent inelastic deformation of unidirectional and symmetric angle-ply CFRP (Carbon Fiber Reinforced Plastics) laminates is developed. The kinematic hardening creep law of Malinin and Khadjinsky and the evolution equation of Armstrong and Frederick are extended to describe the creep deformation of initially anisotropic materials. In particular, the evolution equations of the back stresses of the anisotropic material were formulated by introducing a transformed strain tensor, by which the expression of the equivalent strain rate of the an isotropic material has the identical form as that of the isotropic materials. The resulting model is applied to analyze the time dependent inelastic deformation of symmetric angle ply laminates. Comparison between the predictions and the experimental observations shows that the present model can describe well the time dependent inelastic behavior under different loadings.

Smart Crash Management by Switching the Crash Behavior of Fiber-Reinforced Plastic (FRP) Energy Absorbers With Shape Memory Alloy (SMA) Wires

2013 ◽  
Author(s):  
Moritz Hübler ◽  
Sebastian Nissle ◽  
Martin Gurka ◽  
Sebastian Schmeer ◽  
Ulf Paul Breuer
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Essential Element ◽  
Load Level ◽  
Switching Behavior ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Energy Absorbers ◽  
Energy Absorbing

In this paper two innovative concepts for adjustable energy absorbing elements are presented. These absorbers can serve as an essential element in a smart crash management system e.g. for automotive applications. The adaptability is based on the basic idea of adjusting the stiffness of the absorber in relation to the actual load level in a crash event. Therefore the whole length of the absorber element can be used for energy dissipation. The adjustable absorbers are made from fiber reinforced plastics and shape memory alloy wires as actuating elements. Two possibilities for the basic design of the absorber elements are shown, the performance of the actuating SMA elements is characterized in detail and the switching behavior of the whole elements, between a stiff “on” state and a flexible “off” state, is measured.

Z-pin insertion process for through-thickness reinforced thermoplastic composites

2018 ◽  
Vol 53 (2) ◽  
pp. 173-181 ◽  
Author(s):  
Julian Hoffmann ◽  
Alexander Brast ◽  
Gerhard Scharr
Keyword(s):  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Fiber Waviness ◽  
Reinforced Plastics ◽  
Pullout Tests ◽  
Glass Fiber Reinforced ◽  
Reinforced Plastic ◽  
Novel Method ◽  
Fiber Reinforced Plastics ◽  
Insertion Process

This paper presents a novel method for the ultrasonically assisted insertion of metallic z-pins into thermoplastic composites. Mechanical and microstructural investigations were carried out on glass fiber-reinforced polyamide and polypropylene specimens. The insertion of steel pins into thermoplastic composites led to microstructural changes that differ significantly from the known microstructure of z-pinned thermoset fiber-reinforced plastics. Optical microscopy showed an absence of notable fiber waviness and resin-rich zones around each pin. Instead, the fibers were predominantly deflected in the through-thickness direction by the high insertion forces arising during pin penetration. To gain an initial insight on the resulting properties of the z-pin/thermoplastic interface, the mechanical properties of z-pinned thermoplastic composites under mode I loading were investigated using pullout tests. For reference, the pullout behavior of thermoset carbon fiber-reinforced plastic specimens, reinforced with steel pins was determined too. Due to the poor bonding and lack of friction between the pin and laminate, the determined traction loads of the thermoplastic specimens are well below typical values achieved from pin pullout in thermoset laminates.

Study on Acoustic Emission Detection Technology of Fiber Reinforced Plastic Pressure Vessel

2020 ◽  
Author(s):  
Daoxiang Wei ◽  
Yuqing Yang ◽  
Jun Si ◽  
Xiang Wen
Keyword(s):  
Acoustic Emission ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Glass Fiber Composites ◽  
Reinforced Plastics ◽  
Detection Technology ◽  
Reinforced Plastic ◽  
Emission Detection

Abstract Fiber reinforced plastics are used in pressure vessel manufacturing because of their high strength and corrosion resistance.Defects may occur in the manufacture and use of the pressure vessel. To ensure safe operation of the pressure vessel, it is necessary to conduct periodic safety assessment of the pressure vessel put into operation. It is difficult to evaluate the safety status of fiber-reinforced plastic pressure vessels by conventional nondestructive testing.Acoustic emission detection technology is a dynamic detection method, which has obvious advantages for the performance and fracture process of fiber reinforced plastic materials. ASME section V or ASTM section on acoustic emission detection of FRP pressure vessels, in which the localization of defects is mainly based on acoustic emission instruments. Due to the anisotropy of FRP material, the instrument can only give the area of the defect, and then use other non-destructive testing methods supplementary detection, so the author proposes a regional positioning method, which can locate defects more accurately. In this paper, acoustic emission detection method and lead breaking method were used to simulate the deficiency, and acoustic velocity attenuation and variation of fiber reinforced plastics were studied, and confirmative tests were carried out to obtain the positioning accuracy of the deficiency in different areas.In order to achieve the acoustic emission (AE) response behavior of stretching damage of glass fiber composites with fiber pre-broken and weak bonding, stretching tests and real-time AE monitoring of glass fiber composites were conducted.Experimental results showed that damage model such as matrix cracking and fiber fracture and bending could be occurred in the process of damage and failure. The composition and content of signal frequency of AE is also different because of difference of preset defect.

Micro-Drilling of CFRP Plates Using a High-Speed Spindle

2012 ◽  
Vol 523-524 ◽  
pp. 1035-1040 ◽  
Author(s):  
Keiji Ogawa ◽  
Heisaburo Nakagawa ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama
Keyword(s):  
Cutting Forces ◽  
High Speed ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastics ◽  
Cfrp Plate ◽  
Glass Fiber Reinforced ◽  
Reinforced Plastic ◽  
Micro Drilling ◽  
Fiber Reinforced Plastics

Fundamental characteristics in the micro drilling of carbon fiber reinforced plastic (CFRP) plates are investigated in the present paper. When micro drilling with a high-speed spindle, cutting forces during drilling, such as thrust force and torque, were measured by high resolution dynamometers and drill temperature was monitored by thermography. Comparing the experimental results of CFRP with that of drilling glass fiber-reinforced plastics (GFRP) revealed some unique tendencies. The cutting forces and drill temperature increased drastically. Moreover, drill wear rapidly accelerated. The tool life of CFRP plate drilling is much shorter than that of other plates.

Development of PCD Milling Tool for Carbon-Fiber-Reinforced Plastics

2014 ◽  
Vol 1017 ◽  
pp. 411-414
Author(s):  
Takayuki Kitajima ◽  
Jumpei Kusuyama ◽  
Akinori Yui ◽  
Katsuji Fujii ◽  
Yosuke Itoh
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Polycrystalline Diamond ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Milling Tool ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced

Interest in carbon-fiber-reinforced plastic (CFRP) has been growing for the last several years. CFRP, a composite material made of carbon fibers and resins, has high mechanical characteristics and is well known as a difficult-to-cut material. During the process of drilling or cutting of CFRP, tool wear and delamination occur frequently. In this study, the authors developed a milling tool for CFRP using polycrystalline diamond, and the cutting performance of the developed tool was investigated.

scholarly journals Nano/Micro Hybrid Bamboo Fibrous Preforms for Robust Biodegradable Fiber Reinforced Plastics

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 636
Author(s):  
Junsik Bang ◽  
Hyunju Lee ◽  
Yemi Yang ◽  
Jung-Kwon Oh ◽  
Hyo Won Kwak
Keyword(s):  
Mechanical Properties ◽  
Natural Fiber ◽  
Fibrous Composite ◽  
Cellulose Nanofibers ◽  
Fiber Surface ◽  
High Strength ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Industry Applications

The focus on high-strength and functional natural fiber-based composite materials is growing as interest in developing eco-friendly plastics and sustainable materials increases. An eco-friendly fibrous composite with excellent mechanical properties was prepared by applying the bamboo-derived nano and microfiber multiscale hybridization phenomenon. As a result, the cellulose nanofibers simultaneously coated the micro-bamboo fiber surface and adhered between them. The multiscale hybrid phenomenon implemented between bamboo nano and microfibers improved the tensile strength, elongation, Young’s modulus, and toughness of the fibrous composite. The enhancement of the fibrous preform mechanical properties also affected the reinforcement of biodegradable fiber-reinforced plastic (FRP). This eco-friendly nano/micro fibrous preform can be extensively utilized in reinforced preforms for FRPs and other green plastic industry applications.

Einführung eines heterogenen Kontaktmodells rauer Oberflächen in EHD-Simulationen zur Simulation von faserverstärkten Polymeren in Radialgleitlagern

2021 ◽  
Vol 68 (2) ◽  
Keyword(s):  
Material Properties ◽  
Contact Stiffness ◽  
Material Model ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Macro Scale ◽  
Contact Models ◽  
Factor Maps ◽  
The Impact

The EHL-simulation methods for homogenous materials have to be enhanced to model heterogeneous fiber-reinforced plastics. Because of micro and macro scale material properties, several parameters have to be considered in contact models, e.g. thermal dependency of material properties, material heterogeneity and material non-linearity or viscoelasticity. This paper shows the impact of the stiffness on the micro and macro scale in a fiber-reinforced plastic-steel contact on EHL-simulation results. Especially in the area of micromechanics, the correct combination of the material model and the topography shows a significant influence on the calculated contact stiffness and hence the flow factor maps. Depending on the fiber orientation and film thickness, the contact stiffness variates by a factor of nearly 7.

The Effect of Fiber Winding Angles on the Bending Strength of Fiber-Reinforced Plastic Rods

2007 ◽  
Vol 345-346 ◽  
pp. 661-664
Author(s):  
Hoy Yul Park ◽  
Moon Kyong Na ◽  
Myeong Sang Ahn ◽  
Seog Young Yoon ◽  
Seong Soo Park
Keyword(s):  
Bending Strength ◽  
High Strength ◽  
Shear Stresses ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Bending Load ◽  
The Difference ◽  
Fiber Winding

Fiber-reinforced plastics consist of fibers of high strength and modulus embedded in, or bonded to a matrix with distinct interfaces between them. Because fiber configuration plays a key role in determining mechanical strength of fiber-reinforced plastic rods, especially bending strength of fiber-reinforced plastic rods was measured and simulated numerically in variation with winding angles. Also, stress distribution in fiber-reinforced plastic rods was simulated numerically under the condition of constant bending load to fiber-reinforced plastic rods. The measured bending strength of fiber-reinforced plastic rods in variation with winding angles was different from that of simulated. The difference between measured and simulated results was due to the effect of shear stresses on the strength of fiber-reinforced plastic rods.

Modelling of Manufacturing Processes by FEA-Method for the Production of Natural Fiber-Reinforced Plastics

2007 ◽  
Author(s):  
Christian Doersch ◽  
Joerg Muessig ◽  
Dieter H. Mueller
Keyword(s):  
Natural Fiber ◽  
Cost Effective ◽  
Textile Material ◽  
Market Demand ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Plastic Components

In recent years a growing demand for natural fiber-reinforced plastic components and structures has been observed. One important area of application is transportation, particularly in the automotive industry. Due to market demand, innovative process technologies for fast, cost-effective and quality-driven manufacture of natural fiber-reinforced plastic components is required. This paper will focus on the development of technologies for automised manufacturing of NFRP-components with resin infusion processes. At present NFRP-components are manufactured automatically but without flexibility concerning the deviations of material properties or part geometries. This lack of control in manufacturing results in long cycle times, low process control and high costs. The Bremen Institute for Engineering Design (BIK) is developing and improving machine and process technologies for automised textile handling. The handling system has to meet the requirements of large, limp textile material. The authors have mutually developed methods for the simplified simulation of textiles. The simulation supports the evaluation of textiles and handling devices concerning the ability for better control in manufacturing. To meet these requirements, a simulation of the textile material with the “Finite Element Analysis” method supports the part and process design by reducing developing time and costs. For this purpose, the authors showed a simplified model with a reduced set of material data which is required for the FEA-model.

The Hybrid RTM Process Chain: Automated Insertion of Load Introducing Elements during Subpreform Assembling

2015 ◽  
Vol 794 ◽  
pp. 312-319 ◽  
Author(s):  
Fabian Ballier ◽  
Jan Schwennen ◽  
Julian Berkmann ◽  
Jürgen Fleischer
Keyword(s):  
Automobile Industry ◽  
Process Chain ◽  
Structural Components ◽  
Fiber Reinforced ◽  
Transfer Molding ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastics ◽  
Rtm Process ◽  
Reinforced Plastic ◽  
Fiber Reinforced Plastics

Fiber reinforced plastics are increasingly employed in the automobile industry. The process chain of resin transfer molding offers one approach for realizing structural components made of fiber reinforced plastic in high quantities. In order to increase economic efficiency, automated solutions for the subpreform assembly are required. There is also the need for mechanically highly stressable and at the same time economical joining techniques for joining fiber reinforced plastics with metal. The following article shall provide an approach to meet both of these requirements.

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