In-Situ Failure Identification in Woven Composites Throughout Impact

2006 ◽  
Author(s):  
James Pearson ◽  
Mohanraj Prabhugoud ◽  
Mohammed Zikry ◽  
Kara Peters
Keyword(s):  
Failure Modes ◽  
Contact Forces ◽  
Matrix Cracking ◽  
Woven Composites ◽  
Sensor Failure ◽  
Repeated Impact ◽  
Residual Strains ◽  
Fbg Sensors ◽  
Transverse Strains

In this study, measurements form low-impact velocity experiments including embedded and surface mounted optical fiber Bragg grating (FBG) sensors were used to obtain detailed information pertaining to damage progression in two-dimensional laminate woven composites. The woven composites were subjected to multiple strikes at 2m/s until perforation occurred, and the impactor position and acceleration were monitored throughout each event. From these measurements, we obtained dissipated energies and contact forces. The FBG sensors were embedded and surface mounted at different critical locations near penetration-induced damaged regions. These FBG sensors were used to obtain initial residual strains and axial and transverse strains that correspond to matrix cracking and delamination. The transmission and reflection spectra were continuously monitored throughout the loading cycles. They were used, in combination with the peak contact forces, to delineate repeatable sensor responses corresponding to material failure. From the FBG spectra, fiber and matrix damage were separated by an analysis based on signal intensity and the behavior of individual Bragg peaks as a function of evolving and repeated impact loads. This provided independent feedback on the integrity of the Bragg gratings which can serve to eliminate errors in the strain data such as due to sensor debonding or fracture. The critical indicators present in the sensor spectra for the mapping of these sensor failure modes are derived.

Damage Progression Identification in Woven Composites With Fiber Bragg Grating Sensors

Materials ◽  
2005 ◽  
Author(s):  
James Pearson ◽  
Mohanraj Prabhugoud ◽  
Mohammed Zikry ◽  
Kara Peters
Keyword(s):  
Fiber Bragg Grating ◽  
Contact Forces ◽  
Matrix Cracking ◽  
Woven Composites ◽  
Bragg Grating ◽  
Repeated Impact ◽  
Damage Progression ◽  
Residual Strains ◽  
Fbg Sensors ◽  
Transverse Strains

In this study, measurements from low-impact velocity experiments including embedded and surface mounted optical fiber Bragg grating (FBG) sensors were used to obtain detailed information pertaining to damage progression in two-dimensional laminate woven composites. The woven composites were subjected to multiple strikes at 2m/s until perforation occurred, and the impactor position and acceleration were monitored throughout each event. From these measurements, we obtained dissipated energies and contact forces. The FBG sensors were embedded and surface mounted at different critical locations near penetration-induced damaged regions. These FBG sensors were used to obtain initial residual strains and axial and transverse strains that correspond to matrix cracking and delamination. The transmission and reflection spectra were continuously monitored throughout the loading cycles. They were used, in combination with the peak contact forces, to delineate repeatable sensor responses corresponding to material failure. From the FBG spectra, fiber and matrix damage were separated by an analysis based on signal intensity, the presence of cladding modes, and the behavior of individual Bragg peaks as a function of evolving and repeated impact loads. This provided an independent feedback on the integrity of the Bragg gratings. A comparison by number of impact strikes and dissipated energies corresponding to material perforation indicates that embedding these sensors did not affect the integrity of the woven systems and that these measurements can provide accurate failure strains.

Sensor Networks for In-Situ Failure Identification in Woven Composites Throughout Impact

2007 ◽  
Author(s):  
Ryan Garrett ◽  
Kara Peters ◽  
Mohammed A. Zikry
Keyword(s):  
Sensor Networks ◽  
Optical Fibers ◽  
Matrix Material ◽  
Contact Forces ◽  
Low Velocity Impact ◽  
Woven Composites ◽  
Low Velocity ◽  
Cross Sectional ◽  
Fbg Sensors ◽  
The Impact

In this study, the development of embedded fiber Bragg grating (FBG) sensor networks within composite materials is investigated. Various densities of optical fibers were embedded within two-dimensional woven composite laminates, and low-velocity impact damage responses were evaluated to determine the effects on the mechanical behavior of the laminates. The woven composites were subjected to multiple strikes at 2 m/s until perforation occurred, and the impactor position and acceleration were monitored throughout each event. From these measurements, we obtained dissipated energies and contact forces for specimens with and without embedded optical fibers. Cross sectional optical micrographs of the specimens were also used to determine the local effects of the embedded fibers on neighboring fibers and the surrounding matrix material, both before and after impact events. Multiple FBG sensors were serially multiplexed together to create a single fiber sensing network capable of monitoring damage for each impact event. Residual strain information was gathered through strain distributions along the FBG sensors to map out the near-field and far-field regions with respect to the impact location. The resulting data will be used to better monitor and predict damage in the composite system when combined with global response data from the laminate itself.

Sensor Networks for In-Situ Failure Identification in Woven Composites

2009 ◽  
Author(s):  
Chun Park ◽  
Adam Propst ◽  
Kara Peters ◽  
Mohammed A. Zikry
Keyword(s):  
Sensor Networks ◽  
Composite Laminates ◽  
Failure Modes ◽  
Matrix Cracking ◽  
Woven Composites ◽  
Dissipated Energy ◽  
Low Velocity ◽  
Damage Initiation ◽  
Relaxation Period ◽  
Velocity Surface

This paper presents experimental measurements of the response of woven composite laminates to multiple low-velocity impacts. Damage initiation and progression occur at multiple physical and temporal scales in heterogeneous materials, including fiber breakage, matrix cracking, delamination and matrix relaxation. The sensor networks/interrogators were therefore chosen specifically to provide insight into the order and progression of different failure modes. Measurements of the contact force between the impactor and composite are measured throughout impact. Additionally, the dissipated energy per impact event is also calculated from the impactor velocity. Surface mounted and embedded fiber Bragg grating sensors are used for the measurement of the laminate response. Peak wavelength measurements are performed during impact at 1 kHz, while full-spectral scanning is performed at 5 Hz during relaxation period of the laminate immediately after impact and quasi-statically to measure post-impact residual strain states within the laminate. The results highlight the depth of information embedded within the FBG full-spectral data sensors, as well as the added insight to be gained from combined global-local measurements.

scholarly journals Free-Forging of Pure Titanium with High Reduction of Thickness by Plasma-Carburized SKD11 Dies

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2536
Author(s):  
Tatsuhiko Aizawa ◽  
Tomoaki Yoshino ◽  
Yohei Suzuki ◽  
Tomomi Shiratori
Keyword(s):  
Solid Lubricant ◽  
Pure Titanium ◽  
Solid Lubrication ◽  
Single Shot ◽  
Contact Interface ◽  
Forging Process ◽  
Titanium Wire ◽  
High Reduction ◽  
Residual Strains

A tool steel type SKD11 punch was plasma carburized at 673 K for 14.4 ks at 70 Pa to make carbon supersaturation. This carburized SKD11 punch was employed for upsetting the pure titanium wire with the diameter of 1.00 mm up to the reduction of thickness by 70% in a single shot. Its contact interface to titanium work was analyzed to describe the anti-galling behavior in this forging. Little trace of titanium proved that the galling process was suppressed by the in situ solid lubrication. The isolated free carbon agglomerates are wrought as a solid lubricant to sustain the galling-free forging process. This anti-galling upsetting reduced the residual strains in the forged wires. A long titanium wire with a length of 45 mm was incrementally upset to yield the titanium ribbon with a thickness of 0.3 mm, the width of 2.3 mm, and the length of 50 mm. The grain size of original pure titanium was much reduced to 2 μm on average. A micro-pillared microtexture was imprinted onto this forged titanium ribbon.

EXPERIMENTALLY VALIDATED SIMULATIONS OF BLIND HOLE DRILLING IN 3D WOVEN CARBON/EPOXY COMPOSITE WITH PROCESSING-INDUCED RESIDUAL STRESSES

2021 ◽  
Author(s):  
ARTURO LEOS ◽  
KOSTIANTYN VASYLEVSKYI ◽  
IGOR TSUKROV ◽  
TODD GROSS ◽  
BORYS DRACH
Keyword(s):  
Residual Stresses ◽  
Epoxy Matrix ◽  
Mechanical Performance ◽  
Matrix Cracking ◽  
Woven Composites ◽  
Hole Drilling ◽  
Blind Hole ◽  
Matrix Cracks ◽  
Numerical Predictions ◽  
3D Woven Composites

Manufacturing-induced residual stresses in carbon/epoxy 3D woven composites arise during cooling after curing due to a large difference in the coefficients of thermal expansion between the carbon fibers and the epoxy matrix. The magnitudes of these stresses appear to be higher in composites with high throughthickness reinforcement and in some cases are sufficient to lead to matrix cracking. This paper presents a numerical approach to simulation of development of manufacturing-induced residual stresses in an orthogonal 3D woven composite unit cell using finite element analysis. The proposed mesoscale modeling combines viscoelastic stress relaxation of the epoxy matrix and realistic reinforcement geometry (based on microtomography and fabric mechanics simulations) and includes imaginginformed interfacial (tow/matrix) cracks. Sensitivity of the numerical predictions to reinforcement geometry and presence of defects is discussed. To validate the predictions, blind hole drilling is simulated, and the predicted resulting surface displacements are compared to the experimentally measured values. The validated model provides an insight into the volumetric distribution of residual stresses in 3D woven composites. The presented approach can be used for studies of residual stress effects on mechanical performance of composites and strategies directed at their mitigation.

Sensor Fusion and On-Line Monitoring of Friction Stir Blind Riveting for Lightweight Materials Manufacturing

2021 ◽  
pp. 1-36
Author(s):  
Zhe Gao ◽  
Haris Khan ◽  
Jingjing Li ◽  
Weihong Guo
Keyword(s):  
Sensor Fusion ◽  
Failure Modes ◽  
Processing Parameters ◽  
Data Driven ◽  
Structure Property ◽  
Cross Sectional ◽  
Friction Stir ◽  
In Situ Data ◽  
Lap Shear

Abstract This research focused on developing a hybrid quality monitoring model through combining the data driven and key engineering parameters to predict the friction stir blind riveting (FSBR) joint quality. The hybrid model was formulated through utilizing the in-situ processing and joint property data. The in-situ data involved sensor fusion (force and torque signals) and key processing parameters (spindle speed, feed rate and stacking sequence) for data-driven modeling. The quality of the FSBR joints was defined by the tensile strength. Further, the joint cross-sectional analysis and failure modes in lap-shear tests were employed to confirm the efficacy of the proposed model and development of the process-structure-property relationship.

scholarly journals Moisture Absorption Effects on the Mechanical Properties of Sandwich Biocomposites with Cork Core and Flax/PLA Face Sheets

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7295
Author(s):  
Hom Nath Dhakal ◽  
Chulin Jiang ◽  
Moumita Sit ◽  
Zhongyi Zhang ◽  
Moussa Khalfallah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Moisture Absorption ◽  
Mechanical Performance ◽  
Core Sample ◽  
Environmental Benefits ◽  
Matrix Cracking ◽  
Core Material ◽  
Poly Lactic Acid ◽  
The Core

The aim of this study was to evaluate the moisture absorption behaviour and its influence on the mechanical properties of newly developed sandwich biocomposites with flax fibre-reinforced poly-lactic acid (PLA) face sheets and soft cork as the core material. Three different types of sandwich biocomposite laminates comprised of different layup configurations, namely, non-woven flax/PLA (Sample A), non-woven flax/PLA and cork as core (Sample B) and non-woven flax/paper backing/PLA, cork as core (Sample C), were fabricated. In order to evaluate the influence of moisture ingress on the mechanical properties, the biocomposites were immersed in seawater for a period of 1200 h. The biocomposites (both dry and water immersed) were then subjected to tensile, flexural and low-velocity falling weight impact tests. It was observed from the experimental results that the moisture uptake significantly influenced the mechanical properties of the biocomposites. The presence of the cork and paper in sample C made it more susceptible to water absorption, reaching a value of 34.33%. The presence of cork in the core also has a considerable effect on the mechanical, as well as energy dissipation, behaviours. The results of sample A exhibited improved mechanical performance in both dry and wet conditions compared to samples B and C. Sample A exhibits 32.6% more tensile strength and 81.4% more flexural strength in dry conditions than that in sample C. The scanning electron microscopy (SEM) and X-ray micro-CT images revealed that the failure modes observed are a combination of matrix cracking, core crushing and face core debonding. The results from this study suggest that flax/PLA sandwich biocomposites can be used in various lightweight applications with improved environmental benefits.

scholarly journals Measurement of residual strains as a parameter of matrix cracking in CFRP laminates

2021 ◽  
Vol 15 (4) ◽  
pp. JAMDSM0040-JAMDSM0040
Author(s):  
M. J. Mohammad FIKRY ◽  
Shinji OGIHARA ◽  
Vladimir VINOGRADOV
Keyword(s):  
Matrix Cracking ◽  
Cfrp Laminates ◽  
Residual Strains

scholarly journals Thermal Assessment and In-Situ Monitoring of Insulated Gate Bipolar Transistors in Power Electronic Modules

2019 ◽  
Author(s):  
Erick Gutierrez ◽  
Kevin Lin ◽  
Douglas DeVoto ◽  
Patrick McCluskey
Keyword(s):  
Thermal Cycling ◽  
Failure Modes ◽  
Rapid Determination ◽  
Degradation Process ◽  
In Situ Monitoring ◽  
Power Module ◽  
Insulated Gate Bipolar Transistor ◽  
Die Attach ◽  
Power Modules

Abstract Insulated gate bipolar transistor (IGBT) power modules are devices commonly used for high-power applications. Operation and environmental stresses can cause these power modules to progressively degrade over time, potentially leading to catastrophic failure of the device. This degradation process may cause some early performance symptoms related to the state of health of the power module, making it possible to detect reliability degradation of the IGBT module. Testing can be used to accelerate this process, permitting a rapid determination of whether specific declines in device reliability can be characterized. In this study, thermal cycling was conducted on multiple power modules simultaneously in order to assess the effect of thermal cycling on the degradation of the power module. In-situ monitoring of temperature was performed from inside each power module using high temperature thermocouples. Device imaging and characterization were performed along with temperature data analysis, to assess failure modes and mechanisms within the power modules. While the experiment aimed to assess the potential damage effects of thermal cycling on the die attach, results indicated that wire bond degradation was the life-limiting failure mechanism.

In-Situ Continuous Process for Bonding Glass-Fiber Reinforced Polypropylene to Wood

1999 ◽  
Author(s):  
Karthik Ramani ◽  
Michael Smith ◽  
Heming Dai
Keyword(s):  
Failure Modes ◽  
Continuous Process ◽  
Heating Time ◽  
Bond Line ◽  
Process Conditions ◽  
Processing Times ◽  
Lap Shear ◽  
Glass Fiber Reinforced ◽  
Anisotropic Fiber

Abstract Process conditions are developed for the manufacture of composite reinforcement for oak. Commingled glass and polypropylene fibers are consolidated in-situ on the surface of oak. Processing times from 30 to 120 seconds and pressures from .34 MPa to 1.4 MPa are tested. Micrographs of the composite and bond line reveal anisotropic fiber distribution in the composite, dry reinforcing fibers, voids, and incomplete consolidation. These microstructures are correlated with the processing problems which cause them, including insufficient heating time, poor matrix/glass mixing, and insufficient pressure to suppress void development. Lap shear strength and failure modes are related to microstructural features.

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