scholarly journals Experimental Identification of Statistical Correlation between Mechanical Properties of FRP Composite

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 674 ◽  
Author(s):  
Shufeng Zhang ◽  
Tongzhen Xing ◽  
Haibin Zhu ◽  
Xun Chen
Keyword(s):  
Mechanical Properties ◽  
Composite Structures ◽  
Accurate Determination ◽  
Correlation Coefficients ◽  
Field Method ◽  
Statistical Correlation ◽  
Image Correlation ◽  
Experimental Methodology ◽  
Fiber Reinforced ◽  
Frp Composite

Recent prediction on the heavy statistical correlation between the mechanical properties of fiber reinforced composite (FRP) raises new concerns on the accurate reliability evaluation of composite structures, but such statistical correlation still lacks experimental verification. In this work, an experimental methodology is proposed to determine the statistical correlation between mechanical properties of unidirectional FRP composite. A rectangular shaped carbon fiber reinforced plastic (CFRP) specimen with a circular hole is loaded by tension, and 3D digital image correlation (DIC) is employed to characterize the heterogeneous strain field around the hole. Virtual field method (VFM) is used to derive E11, E22, ν12, and G12 of specimens. Specimen configuration considering fiber angle and hole diameter is optimized to achieve accurate determination of correlation coefficients. Experimental results on the linear correlation coefficients between E11, E22, ν12, and G12 agree well with previous theoretical predictions.

Optical strain measurements on fast moving fiber reinforced polymer rotors using diffraction gratings

2019 ◽  
Vol 86 (3) ◽  
pp. 175-183
Author(s):  
Julian Lich ◽  
Tino Wollmann ◽  
Angelos Filippatos ◽  
Maik Gude ◽  
Robert Kuschmierz ◽  
...  
Keyword(s):  
Rigid Body ◽  
Strain Measurement ◽  
Composite Structures ◽  
Dynamical Behavior ◽  
Image Correlation ◽  
Fiber Reinforced Polymers ◽  
Strain Gauges ◽  
Objective Lens ◽  
Fiber Reinforced ◽  
Body Movements

AbstractIn-situ measurements of the deformation and of the structural dynamical behavior of moving composite structures, such as rotors made of glass fiber reinforced polymers (GFRP), are necessary in order to validate newly developed simulation models. Local methods like strain gauges and fiber Bragg gratings lack spatial resolution, while contactless optical methods like image correlation or speckle interferometry suffer from noise effects in the presence of fast rigid body movements. A novel compact sensor – based on the diffraction grating method – is introduced for spatially and temporally resolved strain measurement. The use of a line camera allows the measurement of vibrations up to several tens of kHz. With a scanning movement, strain fields at submillimeter resolution can be recorded. The use of two diffraction orders and an objective lens reduces cross sensitivities to rigid body movements on the strain measurement by two to three orders of magnitude. A validation on a GFRP probe was conducted in a quasi-static tensile test with an optical extensometer up to 14500 µϵ. Furthermore, a strain measurement on a moving rotor at surface speeds up to 75 m/s was performed and the results were compared with those of strain gauges as a gold standard. The statistical standard deviation was around 10 µϵ and independent of the rotational speed.

Effect of Mechanical Properties on Various Surface Treatment Processes of Banana/Cotton Woven Fabric Vinyl Ester Composite

2017 ◽  
Vol 867 ◽  
pp. 41-47 ◽  
Author(s):  
Chitra Umachitra ◽  
N.K. Palaniswamy ◽  
O.L. Shanmugasundaram ◽  
P.S. Sampath
Keyword(s):  
Mechanical Properties ◽  
Composite Structures ◽  
Natural Fiber ◽  
Natural Fibers ◽  
Surface Treatments ◽  
Fiber Reinforced Polymer ◽  
Woven Fabric ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Structural Applications

Natural fibers have been used to reinforce materials in many composite structures. Many types of natural fibers have been investigated including flax, hemp, ramie, sisal, abaca, banana etc., due to the advantage that they are light weight, renewable resources and have marketing appeal. These agricultural wastes can also be used to prepare fiber reinforced polymer hybrid composites in various combinations for commercial use. Application of composite materials in structural applications has presented the need for the engineering analysis. The present work focuses on the fabrication of polymer matrix composites by using natural fibers like banana and cotton which are abundant in nature and analysing the effect of mechanical properties of the composites on different surface treatments on the fabric. The effect of various surface treatments (NaOH, SLS, KMnO4) on the mechanical properties namely tensile, flexural and impact was analyzed and are discussed in this project. Analysing the material characteristics of the compression moulded composites; their results were measured on sections of the material to make use of the natural fiber reinforced polymer composite material for automotive seat shell manufacturing.

Stereomicroscopic optical method for the assessment of load transfer patterns across the wood-adhesive bond interphase

Holzforschung ◽  
2015 ◽  
Vol 69 (5) ◽  
pp. 653-660 ◽  
Author(s):  
Matthew Schwarzkopf ◽  
Lech Muszyński
Keyword(s):  
Mechanical Properties ◽  
Load Transfer ◽  
Mechanical Performance ◽  
Adhesive Bond ◽  
Wood Adhesive ◽  
Surface Strain ◽  
Image Correlation ◽  
Optical Measurements ◽  
Experimental Methodology ◽  
Full Field

Abstract The mechanical performance of wood-based composites is determined by the mechanical properties of their individual components and the effective load transfer between these components. In laminated wood composites, this load transfer is facilitated by the adhesive bond. The experimental methodology developed in this study measures and analyzes the full-field deformation and strain distributions across the loaded wood-adhesive interphase at a micromechanical level. Optical measurements were performed based on the principles of digital image correlation by a stereomicroscopic camera system. This system allows the monitoring of in-plane deformations as well as out-of-plane displacements, providing full-field 3D surface strain maps across the adhesive bond. These measurements can be used to improve the understanding of the load transfer between the adherents and the contribution of the adhesive to the mechanical properties of the bulk composite and serve as a quantitative input for numerical modeling and simulations aimed at the improvement of the products.

Measurement of tensile mechanical properties of fiber reinforced plastic rebars by 3D digital image correlation

2020 ◽  
Vol 62 (4) ◽  
pp. 422-428
Author(s):  
Feipeng Zhu ◽  
Pengxiang Bai ◽  
Dong Lei
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Curved Surfaces ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic

Abstract Fiber reinforced plastic (FRP) plays an increasingly important role in many engineering fields due to its advantages of light weight, low cost, simple maintenance, and excellent corrosion resistance. The conventional contact methods for deformation measurement, such as strain gauge and mechanical extensometer, have some shortcomings in measuring the strain of FRP rebar specimens with spiral curved surfaces. Therefore, the non-contact three-dimensional digital image correlation (3D-DIC) technique was employed to determine the tensile mechanical properties of two types of FRP rebar specimens, i. e. glass FRP (GFRP) and carbon FRP (CFRP) specimens. Uniaxial tensile tests with three different loading rates were conducted to obtain the stress-strain curves, elastic modulus, tensile strength and percentage total extension at maximum force of these two FRP specimens. Experimental results indicate that the axial-strain field of all FRP rebar specimens present nonuniform distribution and that the stress of GFRP and CFRP rebars varies linearly with the strain. Moreover, no yielding phenomenon was observed from the stress-strain curves, which indicates that both GFRP and CFRP rebars belong to the group of typical brittle materials. The dispersion of elastic moduli obtained using 3D-DIC is better than that using a clip-on extensometer, which demonstrates the validity of 3D-DIC for the determination of tensile mechanical properties of FRP rebars with spiral curved surfaces.

scholarly journals Weibull Probabilistic Model of Moisture Concentration Build Up in a Fiber Graphite/Epoxy Polymer Composite under Varying Hydrothermal Conditions

2020 ◽  
Vol 65 (1) ◽  
pp. 27-37
Author(s):  
Boucham Belhadj ◽  
Lousdad Abdelkader ◽  
Alaa Chateauneuf
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Composite Structures ◽  
Moisture Absorption ◽  
Environmental Control ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Hydrothermal Conditions ◽  
Glass Fiber Reinforced ◽  
Structural Applications

Advanced mechanical and structural applications require accurate assessment and better knowledge of the damage state during elaboration and service. The development of life prediction methodologies for Glass Fiber Reinforced Polymers (GFRPs) has increased with the use of composites in different industries. It is important to develop through thickness degradation analyses due to ageing in order to predict its effect on the lifetime of composite structures. This study aims to model the moisture absorption, the concentration of the absorbed fluid and the reduction of mechanical properties in the through the thickness direction of a GFRPs structure. The water absorption behavior of woven glass fiber reinforced cyanate ester composites used in the plenum of the air conditioning pack of aircraft environmental control system has been modeled. The combined models describe the diffusion procedure primarily at material level and continuously at structure level. The amount of the absorbed moisture can be crucial for the mechanical behavior of the structure. Therefore, there is a need for a better understanding of the evolution of mechanical properties during ageing. The procedure utilizes the results of the diffusion model to calculate the moduli degradation during the water uptake process. Predictive models have been proposed by considering different sections throughout the thickness and provide a solid background for modeling the long term behavior of a structure exposed at different temperature and different time period. This work performed the numerical studies on the effect of moisture, temperature and presents some useful instructions for the evaluation of such composite structures.

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