scholarly journals Examining Cfrp Laminate Layup with Contact-Mode Ultrasonic Measurements

1993 ◽  
Vol 2 (2) ◽  
pp. 096369359300200 ◽  
Author(s):  
D K Hsu ◽  
F J Margetan
Keyword(s):  
Angular Dependence ◽  
Shear Waves ◽  
Ultrasonic Signal ◽  
Thickness Direction ◽  
Contact Mode ◽  
Cfrp Laminate ◽  
Cfrp Laminates ◽  
Ultrasonic Measurements

This letter describes contact-mode ultrasonic measurements for evaluating the layup configuration of cross-plied CFRP laminates, particularly the [0m/90n] l layup. Polarization and velocity of shear waves propagating in the thickness direction were used in deducing the percentages of 0 and 90 degree plies. The angular dependence of an acousto-ultrasonic signal was used in the determination of in-plane fiber directions.

scholarly journals Bond between Concrete and Multi-Directional CFRP Laminates

2010 ◽  
Vol 133-134 ◽  
pp. 917-922 ◽  
Author(s):  
José Sena-Cruz ◽  
Joaquim Barros ◽  
Mário Coelho
Keyword(s):  
Carbon Fiber ◽  
Civil Engineering ◽  
Fiber Reinforced Polymers ◽  
Structural Elements ◽  
Engineering Applications ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Cfrp Laminate ◽  
Cfrp Laminates ◽  
Pullout Tests

Recently, laminates of multi-directional carbon fiber reinforced polymers (MDL-CFRP) have been developed for Civil Engineering applications. A MDL-CFRP laminate has fibers in distinct directions that can be arranged in order to optimize stiffness and/or strength requisites. These laminates can be conceived in order to be fixed to structural elements with anchors, resulting high effective strengthening systems. To evaluate the strengthening potentialities of this type of laminates, pullout tests were carried out. The influence of the number of anchors, their geometric location and the applied pre-stress are analyzed. The present work describes the carried-out tests and presents and analyzes the most significant obtained results.

scholarly journals Characterization and Application of a Grazing Angle Objective for Quantitative Infrared Reflection Microspectroscopy

1995 ◽  
Vol 49 (3) ◽  
pp. 354-360 ◽  
Author(s):  
Stephen V. Pepper
Keyword(s):  
Angular Dependence ◽  
Grazing Angle ◽  
Fresnel Reflection ◽  
Angular Aperture ◽  
Incident Intensity ◽  
Specular Reflectance ◽  
Fresnel Reflection Coefficient ◽  
Infrared Reflection ◽  
Good Agreement

A grazing angle objective on an infrared microspectrometer is studied for quantitative spectroscopy by considering the angular dependence of the incident intensity within the objective's angular aperture. The assumption that there is no angular dependence is tested by comparing the experimental reflectance of Si and KBr surfaces with the reflectance calculated by integrating the Fresnel reflection coefficient over the angular aperture under this assumption. Good agreement was found, indicating that the specular reflectance of surfaces can straightforwardly be quantitatively integrated over the angular aperture without considering nonuniform incident intensity. This quantitative approach is applied to the thickness determination of dipcoated Krytox on gold. The infrared optical constants of both materials are known, allowing the integration to be carried out. The thickness obtained is in fair agreement with the value determined by ellipsometry in the visible. Therefore, this paper illustrates a method for more quantitative use of a grazing angle objective for infrared reflectance microspectroscopy.

High Frequency Ultrasonic Measurements

1988 ◽  
Vol 21 (5) ◽  
pp. 133-136
Author(s):  
N Zarsav
Keyword(s):  
High Frequency ◽  
Polymer Coating ◽  
Steel Sheet ◽  
Lamb Waves ◽  
Thin Plates ◽  
Design Features ◽  
Degree Of Cure ◽  
Double Probe ◽  
Ultrasonic Measurements

The use of high frequency ultrasonic Lamb waves to measure the thickness of thin plates and foils, is discussed and the feasibility of their application to the determination of the degree of cure of polymer coating on coated tin plated steel sheet (as used by the food can industry) is evaluated. The paper also discusses briefly the design features of the purpose built precision double probe ultrasonic goniometer used to carry out these measurements.

scholarly journals State space approach with FEM for the determination of structural behaviour of composite plates

2017 ◽  
Vol 8 (4) ◽  
pp. 468-483
Author(s):  
Asad Shukri Albostami ◽  
Zhangjian Wu ◽  
Zhenmin Zou
Keyword(s):  
Plate Thickness ◽  
Composite Plates ◽  
Thickness Direction ◽  
Middle Plane ◽  
Structural Behaviour ◽  
State Space Approach ◽  
Content Type ◽  
Simply Supported ◽  
Space Approach

Purpose An analytical investigation has been carried out for a simply supported rectangular plate with two different loading conditions by using 3D state space approach (SSA). Also, the accurate location of the neutral plane (N.P.) through the thickness of the plate can be identified: the N.P. is shifted away from the middle plane according to the loading condition. The paper aims to discuss these issues. Design/methodology/approach SSA and finite element method are used for the determination of structural behaviour of simply supported orthotropic composite plates under different types of loading. The numerical results from a finite element model developed in ABAQUS. Findings The effect of the plate thickness on displacements and stresses is described quantitatively. It is found that the N.P. of the plate, identified according to the values of the in-plane stresses through the thickness direction, is shifted away from the middle plane. Further investigation shows that the position of the N.P. is loading dependant. Originality/value This paper describe the effect of the plate thickness on displacements and stresses quantitatively by using an exact solution called SSA. Also, it is found that the N.P. of the plate, identified according to the values of the in-plane stresses through the thickness direction, is shifted away from the middle plane. Further investigation shows that the position of the N.P. is loading dependant.

Two Tiered Analysis of a CFRP Laminate Imbedded With Magnetostrictive Particles

2010 ◽  
Author(s):  
George Currie ◽  
Dustin Spayde ◽  
Oliver Myers
Keyword(s):  
Experimental Approach ◽  
Analytical Investigation ◽  
Experimental Investigations ◽  
Cfrp Laminate ◽  
Cfrp Laminates ◽  
Excitation Coil ◽  
Laminate Theory ◽  
Linear Sections ◽  
Strength And Stiffness ◽  
Fundamental Equations

The overall purpose of this research is to characterize the affects of imbedding magnetostrictive particles (MSP) in a CFRP laminate for the purpose of nondestructive evaluation. This paper details an investigation using an analytical and experimental approach. At the time of this publication, both the analytical and experimental investigations are in a preliminary stage and the results have not yet converged. The analytical investigation utilizes fundamental equations for the magnetomechanical properties of the MSP and classical laminate theory for the strength and stiffness of the CFRP laminate to obtain a model of the combination. It is assumed that the magnetomechanical relationship of the MSP layer is a function of the prestress acting on the layer. This relationship is nonlinear in nature but is broken down into a number of linear sections to facilitate analysis. This prestress acting on the MSP layer is a result of the CFRP laminate’s stiffness resisting the induced strain of the MSP layer. Classical laminate theory is used to obtain the value of the prestress as a function of this induced strain. As would be expected, this analysis becomes an iterative process. The induced strain is calculated based on a prestress level of zero. This strain is then used to calculate the amount of stress in the CFRP laminate which becomes the prestress value, and the process is repeated until convergence is reached. Unidirectional CFRP laminates are used in this analysis. The experimental approach involved testing a collection of composite beams imbedded with MSP using a scanner that surrounded the beams. The scanner was composed of an excitation coil and a sensing coil. A detailed schematic of the scanner is included in the paper showing the slide along which the scanner apparatus moved, and the sensing coil surrounded by the excitation coil. The samples used in this analysis were constructed from unidirectional prepreg carbon fiber with varying internal delaminations, ply orientations, and number of plies. A program was constructed that allowed the user to control the signal being output to the excitation coil as well as record data from the sensing coil. The results presented in this paper are not final and will be used to create a foundation for continuation of this research.

Theory underlying the determination of initial stresses from the results of ultrasonic measurements

1971 ◽  
Vol 7 (6) ◽  
pp. 676-679 ◽  
Author(s):  
A. N. Guz' ◽  
F. G. Makhort ◽  
O. I. Gushcha ◽  
V. K. Lebedev
Keyword(s):  
Initial Stresses ◽  
Ultrasonic Measurements
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