Reusable piezo-sandwiched PTFE film for in-process monitoring of advanced composites

2021 ◽  
pp. 1045389X2110026
Author(s):  
Elie Mahfoud ◽  
Mohammad Harb
Keyword(s):  
Electromechanical Coupling ◽  
Lamb Waves ◽  
Fiber Composite ◽  
Composite Plates ◽  
Assessment System ◽  
Film Material ◽  
Carbon Fiber Composite ◽  
Low Frequencies ◽  
Ptfe Film ◽  
Manufacturing Defects

Environmental and cost-saving advantages derived from the use of composites attract aerospace and automotive industries as these materials offer significant structural and aerodynamic advantages over traditional metal structures. The composites industry, however, is concerned with the manufacturing processes as they cannot provide fast enough cycle time to match metal alloy processes. Our research aims to develop a sensing technology in the form of a reusable in situ cure monitoring and assessment system that can predict the formation of manufacturing defects and monitor the degree of cure. Thin-film material is chosen from various PTFE-based material by prioritizing the debonding effect and signal transmission through the composite part. Then, the film is used to sandwich piezoelectric actuators and sensors to monitor out-of-autoclave carbon fiber composite plates using ultrasonic Lamb waves by temporarily adhering to the manufactured part creating an effective electromechanical coupling between the sensing film and the laminate. Initial results, through the analysis of the fundamental antisymmetric A0 mode at low frequencies, indicate that analyzing the velocity and amplitude of these waves over cure time determines gelation and vitrification points. Experimental results have also proved the feasibility of using such a reusable film for different curing cycles, always determining certain cure parameters.

Structural Health Monitoring of Composite Plates Subjected to Impacts Using the Electromechanical Impedance Technique

2008 ◽  
Author(s):  
Karina M. Tsuruta ◽  
Leandro R. Cunha ◽  
Raquel S. L. Rade ◽  
Domingos A. Rade
Keyword(s):  
Structural Health Monitoring ◽  
Impact Energy ◽  
Health Monitoring ◽  
Fiber Composite ◽  
Composite Plates ◽  
Carbon Fiber Composite ◽  
Monitoring Method ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
Functional Relations

The aim of this paper is to evaluate the use of the Structural Health Monitoring (SHM) technique based on the concept of electromechanical impedance for the assessment of low-energy impact damage in laminated carbon-fiber composite plates. The experiments were carried-out by using an especially designed pendulum, and were planned in such a way to accommodate a range of test conditions, such as impact energy and dimension of the impacting piece. Also, it was investigated the influence of the frequency band in which the impedance functions are measured. Additionally, statistical metamodels were built aiming at establishing functional relations between the values of the damage metric and impact energy for single and multiple impacts. The obtained results demonstrate the capability of the monitoring method to identify various damage levels corresponding to different impact conditions.

Anisotropic Behavior Analyzed by Laser-Generated Lamb Waves for Fiber Composite Plates

1999 ◽  
Vol 16 (7) ◽  
pp. 518-519 ◽  
Author(s):  
Jian-chun Cheng ◽  
Jun-bo Han ◽  
Shu-yi Zhang ◽  
Yves Berthelot
Keyword(s):  
Lamb Waves ◽  
Fiber Composite ◽  
Composite Plates ◽  
Anisotropic Behavior

Torsional Failure of Carbon Fiber Composite Plates Versus Stainless Steel Plates for Comminuted Distal Fibula Fractures

2016 ◽  
Vol 37 (5) ◽  
pp. 548-553 ◽  
Author(s):  
William K. Wilson ◽  
Randal P. Morris ◽  
Adam J. Ward ◽  
Nikoletta L. Carayannopoulos ◽  
Vinod K. Panchbhavi
Keyword(s):  
Stainless Steel ◽  
Carbon Fiber ◽  
Fiber Composite ◽  
Composite Plates ◽  
Steel Plates ◽  
Carbon Fiber Composite ◽  
Distal Fibula

Delamination Detection in Composite Plates Using Linear and Nonlinear Ultrasonic Guided Waves

2019 ◽  
Author(s):  
Yanfeng Shen ◽  
Mingjing Cen
Keyword(s):  
Wave Propagation ◽  
Guided Waves ◽  
Fiber Composite ◽  
Composite Plates ◽  
Ultrasonic Guided Waves ◽  
Carbon Fiber Composite ◽  
Laser Doppler Vibrometry ◽  
Delamination Detection ◽  
Nonlinear Ultrasonic ◽  
Linear And Nonlinear

Abstract This paper presents a delamination detection strategy for composite plates using linear and nonlinear ultrasonic guided waves via the wave field imaging and signal processing based on Scanning Laser Doppler Vibrometry (SLDV). The anisotropic elastodynamics in composite plates is first studied. Two numerical methods are deployed to analyze the wave mechanics within the composite plates. The Semi-analytical Finite Element (SAFE) method is utilized to obtain the dispersion curves and mode shapes for a carbon fiber composite plate by bonding two quasi-isotropic carbon fiber composite panels together. The Local Interaction Simulation Approach has been employed to investigate the wave propagation and interaction with the delamination. Contact Acoustic Nonlinearity (CAN) between the delamination interfaces during wave damage interaction is presented as a potential mechanism for delamination detection. After developing an in-depth understanding of the wave propagation and wave damage interaction mechanism, active sensing experiments are conducted using the Piezoelectric Wafer Active Sensors (PWAS) and the Scanning Laser Doppler Vibrometry (SLDV). Two delamination imaging methodologies are presented. The first one utilizes the total wave energy to detect the delamination, taking advantage of the trapped modes within the delaminated area. The second one adopts the nonlinear second harmonic imaging algorithm, highlighting the nonlinear interaction traces at the delamination region. The damage detection images are finally compared and fused to provide detailed diagnostic information of the delamination. The damage imaging technique presented in this paper possesses great potential in material evaluation and characterization applications. This paper finishes with summary, concluding remarks, and suggestions for future work.

scholarly journals Guided Waves for Damage Detection in Complex Composite Structures: The Influence of Omega Stringer and Different Reference Damage Size

2020 ◽  
Vol 10 (9) ◽  
pp. 3068
Author(s):  
Jochen Moll ◽  
Christian Kexel ◽  
Jens Kathol ◽  
Claus-Peter Fritzen ◽  
Maria Moix-Bonet ◽  
...  
Keyword(s):  
Composite Structures ◽  
Guided Waves ◽  
Fiber Composite ◽  
Composite Plates ◽  
Guided Wave ◽  
Probability Of Detection ◽  
Carbon Fiber Composite ◽  
Technical Validation ◽  
Pod Analysis ◽  
The Impact

The third dataset dedicated to the Open Guided Waves platform aims at carbon fiber composite plates with an additional omega stringer at constant temperature conditions. The two structures used in this work are representative for real aircraft components. Comprehensive measurements were recorded in order to study (I) the impact of the omega stringer on guided wave propagation, and (II) elliptical reference damages of different sizes located at three separate positions on the structure. Measurements were recorded for narrowband excitation (5-cycle toneburst with varying carrier frequencies) and broadband excitation (using chirp waveforms). The paper presents the results of a technical validation including numerical modelling, and enables further research, for example related to probability of detection (POD) analysis.

STRETCHED EXPONENTIAL RELAXATION ANALYSIS OF THE MOISTURE DIFFUSION IN CARBON FIBER SAMPLES

1994 ◽  
Vol 08 (16) ◽  
pp. 965-975 ◽  
Author(s):  
V. GIARETTO ◽  
G. RUSCICA ◽  
E. MIRALDI
Keyword(s):  
Carbon Fiber ◽  
Mass Transport ◽  
Moisture Transfer ◽  
Plastic Material ◽  
Fiber Composite ◽  
Composite Plates ◽  
Moisture Diffusion ◽  
Carbon Fiber Composite ◽  
Stretched Exponential ◽  
Exponential Relaxation

The ending part of the desorption of water molecules from carbon fiber composite plates is analyzed in terms of a stretched exponential decay function. The physical process of mass transport right to the fibers epoxy interfaces through the plastic material is discussed. Further, by analogy with the heat transfer mechanism, it is shown that the parameters useful to describe the mass variations in time are related to the mass diffusion coefficient and to the Biot number for the mass transport through a characteristic length of the sample, namely, the ratio between its volume and surface. The global average drift velocity of a water molecule through the sample has been introduced to describe the moisture transfer process. The experimental data fit very well to the theoretical curves and validate the global approach used.

scholarly journals Interdigital Piezopolymer Transducers for Time of Flight Measurements with Ultrasonic Lamb Waves on Carbon-Epoxy Composites under Pure Bending Stress

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Andrea Bulletti ◽  
Lorenzo Capineri
Keyword(s):  
Lamb Waves ◽  
Fiber Composite ◽  
Time Of Flight ◽  
Bending Moment ◽  
Wave Mode ◽  
Guided Wave ◽  
Pure Bending ◽  
Carbon Fiber Composite ◽  
Central Wavelength ◽  
Bending Stresses

Interdigital transducers fabricated with piezopolymer film have been realized to excite ultrasonic Lamb waves in a composite laminate subjected to pure bending stresses. Lamb waves were generated and detected in a cross-ply [0°/90°] 4 mm thick carbon-fiber composite, by using two interdigital transducers in pitch-catch configuration. We demonstrate that the choice of the piezopolymer transducer technology is suitable for this type of investigation and the advantages of the proposed transducer assembly and bonding are described. A full set-up is described to determine the relationship between the time of flight of the recorded signals and the applied bending moment. Interdigital transducers were designed according to simulations of the dispersion curves, in order to operate at a central frequency of 450 kHz. This frequency corresponds to a central wavelength of 16 mm and to a group velocity of about 6000 m/s for the first symmetric guided wave mode. The variations in the time of flight of ultrasonic recorded signals were measured as a function of the variations in the bending moment. The static and dynamic load tests were in good agreement with strain gage measurements performed in the micro deformation range (0–1400 µm/m).

Design and Validation of a Carbon-Fiber Collapsible Hinge for Space Applications: A Deployable Boom

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Davide Piovesan ◽  
Mirco Zaccariotto ◽  
Carlo Bettanini ◽  
Marco Pertile ◽  
Stefano Debei
Keyword(s):  
Carbon Fiber ◽  
Fiber Composite ◽  
Higher Order ◽  
Simulation Software ◽  
Carbon Fiber Composite ◽  
Space Applications ◽  
Low Frequencies ◽  
Locking Mechanism ◽  
Physical Prototype ◽  
Nonlinear Elastic

This work presents an analysis and validation of a foldable boom actuated by tape-spring foldable elastic hinges for space applications. The analytical equations of tape-springs are described, extending the classical equations for isotropic materials to orthotropic carbon-fiber composite materials. The analytical equations which describe the buckling of the hinge have been implemented in a multibody simulation software where the hinge was modeled as a nonlinear elastic bushing and the boom as a rigid body. In the experimental phase, the boom was fabricated using a thin layer carbon-fiber composite tube, and the residual vibrations after deployment were experimentally tested with a triaxial accelerometer. A direct comparison of the simulation with the physical prototype pointed out the dangerous effect of higher order vibrations which are difficult to capture in simulation. We observed that while the vibrational spectra of simulations and experiments were compatible at low frequencies during deployment, a marked difference was observed at frequencies beyond 30 Hz. While difficult to model, higher order frequencies should be carefully accounted for in the design of self-deployable space structures. Indeed, if tape-springs are used as a self-locking mechanism, the higher vibrational modes could have enough energy to unlock the structure during operation.

Mechanical Analyses of Repeatedly Processed Polypropylene/Carbon Fiber Composite Plates

2010 ◽  
Vol 97-101 ◽  
pp. 1794-1796 ◽  
Author(s):  
Ching Wen Lou ◽  
Kuo Chen Chang ◽  
Chien Teng Hsieh ◽  
Tung Lung Kuo ◽  
Jia Horng Lin
Keyword(s):  
Mechanical Property ◽  
Carbon Fiber ◽  
Composite Plate ◽  
Fiber Composite ◽  
Composite Plates ◽  
Carbon Fiber Composite ◽  
Three Point Bending ◽  
Single Screw Extrusion ◽  
The Times ◽  
The Impact

Polymer blending was used by adding different proportions (5, 10, 15 and 20 wt %) of the short carbon fiber into the high impact polypropylene (PP) matrix to reinforce the matrix’s mechanical property. The carbon fiber was melt blended with the PP matrix. The mixture was repeatedly processed by the single-screw extrusion into chips, which later became the composite plate by the injection molding machine. In this study, the effect of the repeatedly process on the PP/Carbon fiber composite plate’s mechanical property was examined. The tensile strength of the mixture having one process and six processes were 886 N and 857 N respectively. The impact strength of the composite plates processed for once was 334 J/m while that of the plates processed for six times was 325 J/m. The three-point bending of the composite plate processed once was 30 MPa when that of the plate processed for six times was 28 MPa. The more the times of the process, the weaker the composite plate’s mechanical property became. The carbon fiber was used to reinforce PP’s mechanical property. This study will be applied in the industry.

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