scholarly journals Low Velocity Impact Energy Monitoring and Recognition of Composite Laminates with Variable Thickness Based on Optical Fiber Sensor Network

2021 ◽  
Vol 11 (2) ◽  
pp. 584
Author(s):  
Guan Lu ◽  
Tianyu Zhu ◽  
Yiming Xu
Keyword(s):  
Optical Fiber ◽  
Impact Energy ◽  
Variable Thickness ◽  
Composite Laminates ◽  
Optical Fiber Sensor ◽  
Low Velocity Impact ◽  
Average Error ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

At present, most of the research on low velocity impact of composite laminates focuses on load location and damage assessment. To provide further early warnings about structural impact damage, impact energy can be monitored and identified. For high strength composite laminates with variable thickness, in order to further accurately evaluate the impact energy, it is necessary to adopt more suitable dynamic load signal analysis and impact energy identification methods. Therefore, a new low velocity impact monitoring and identification method for composite plates with variable thickness is proposed. All impact sample signals collected by optical fiber sensor network are decomposed by whitening Empirical Mode Decomposition (EMD); the energy feature set is established according to the impact energy eigenvalue of sample signal; according to the first order component of signal decomposition, the thickness coefficient is determined and the energy feature set is modified to evaluate the actual impact energy. Meanwhile, combined with optical fiber sensing and signal processing technology, an impact energy monitoring system has been established, and the low velocity impact monitoring and identification experiments of composite laminates with variable thickness were carried out. The proposed energy identification method successfully identified 1–3 J impact energy with an average error of 4.82%, and the average error of large thickness area with low sensitivity was significantly reduced from 13.25% to 5.67%. The results show that the thickness coefficient correction method based on whitening EMD can evaluate the low velocity impact energy more accurately, and the thickness coefficient correction step significantly improves the recognition performance.

Experimental Research on the Low Velocity Impact Damage of CCF300/QY8911 Composite Laminates

2012 ◽  
Vol 583 ◽  
pp. 179-182
Author(s):  
Hai Ming Hong ◽  
Ming Li ◽  
Jian Yu Zhang ◽  
Yi Ning Zhang
Keyword(s):  
Impact Energy ◽  
Composite Laminates ◽  
Low Velocity Impact ◽  
Test Machine ◽  
Low Velocity ◽  
Velocity Impact ◽  
Damage Pattern ◽  
The Impact ◽  
Dent Depth ◽  
Delamination Damage

A group of low-velocity impact tests on CCF300/QY8911 composite laminates were implemented by the low-velocity drop hammer test machine. The dent depth and the internal damage pattern with corresponding impact energy were studied, the internal delamination damage state of laminates after impact were observed through thermal layer exposing tests, and the mechanism of low-velocity impact delamination damage were discussed. The results indicated that there existed a significant inflection point in the curve of impact energy verse dent depth of CCF300/QY8911 composite material, which was also the transition point of different damage patterns. When the impact energy was smaller than the inflection energy, the damage pattern consisted mainly of matrix flaws and delamination damages, but when the impact exceeded the inflection energy, delamination damage hardly expanded while the expansion of damage was mainly fiber break.

Response and failure modes of biaxial warp-knitted flexible composite subject to low-velocity impact

2021 ◽  
pp. 152808372110154
Author(s):  
Ziyu Zhao ◽  
Tianming Liu ◽  
Pibo Ma
Keyword(s):  
Impact Energy ◽  
Linear Density ◽  
Failure Modes ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Minor Effect ◽  
Low Velocity ◽  
Velocity Impact ◽  
Flexible Composites ◽  
The Impact

In this paper, biaxial warp-knitted fabrics were produced with different high tenacity polyester linear density and inserted yarns density. The low-velocity impact property of flexible composites made of polyurethane as matrix and biaxial warp-knitted fabric as reinforcement has been investigated. The effect of impactor shape and initial impact energy on the impact response of flexible composite is tested. The results show that the initial impact energy have minor effect on the impact response of the biaxial warp-knitted flexible composites. The impact resistance of flexible composite specimen increases with the increase of high tenacity polyester linear density and inserted yarns density. The damage morphology of flexible composite materials is completely different under different impactor shapes. The findings have theoretical and practical significance for the applications of biaxial warp-knitted flexible composite.

Effect of SiO2 Nanoparticles on the Mechanical and Low Velocity Impact Properties of Epoxy/Glass Composites

2016 ◽  
Vol 838 ◽  
pp. 29-35
Author(s):  
Michał Landowski ◽  
Krystyna Imielińska
Keyword(s):  
Flexural Strength ◽  
Energy Absorption ◽  
Impact Energy ◽  
Epoxy Matrix ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Nanoparticle Suspension ◽  
Impact Properties ◽  
Velocity Impact ◽  
The Impact

Flexural strength and low velocity impact properties were investigated in terms of possibile improvements due to epoxy matrix modification by SiO2 nanoparticles (1%, 2%, 3%, 5%, 7%wt.) in glass/epoxy laminates formed using hand lay-up method. The matrix resin was Hexion L285 (DGEBA) with Nanopox A410 - SiO2 (20 nm) nanoparticle suspension in the base epoxy resin (DGEBA) supplied by Evonic. Modification of epoxy matrix by variable concentrations of nanoSiO2 does not offer significant improvements in the flexural strength σg, Young’s modulus E and interlaminar shear strength for 1% 3% and 5% nanoSiO2 and for 7% a slight drop (up to ca. 15-20%) was found. Low energy (1J) impact resistance of nanocomposites represented by peak load in dynamic impact characteristics was not changed for nanocompoosites compared to the unmodified material. However at higher impact energy (3J) nanoparticles appear to slightly improve the impact energy absorption for 3% and 5%. The absence or minor improvements in the mechanical behaviour of nanocomposites is due to the failure mechanisms associated with hand layup fabrication technique: (i.e. rapid crack propagation across the extensive resin pockets and numerous pores and voids) which dominate the nanoparticle-dependent crack energy absorption mechanisms (microvoids formation and deformation).

Compressive Strength of CCF300/QY8911 Composite Laminates with LVI Damage

2012 ◽  
Vol 583 ◽  
pp. 203-206
Author(s):  
Hai Ming Hong ◽  
Ming Li ◽  
Jian Yu Zhang ◽  
Yi Ning Zhang
Keyword(s):  
Compressive Strength ◽  
Impact Energy ◽  
Composite Laminates ◽  
Inflection Point ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Damage Area ◽  
Compressive Performance ◽  
The Impact ◽  
Dent Depth

A series of low-velocity impact tests and residual compressive strength tests after impacts on CCF300/QY8911 composite materials were carried out to study the mechanism of compression failure of the laminates after low-velocity impact. The curves of impact energy verse dent depth and impact energy verse the damage area was obtained. And the residual compressive strength and stiffness after impact verse damage parameters were analyzed. The results showed that when the impact energy exceeded the inflection point, as the impact energy increased, the dent depth on the impacted surface of the laminates notably increased while the damage area of the internal layers merely increased slowly. If the impact energy was continued to increase, the expansion of the laminates' internal damage mainly consisted of fiber breaks. The main reason for the decrease in compressive performance of composite laminates was inside delamination between layers, while in the case in which impact energy exceeded the inflection point, there were no obvious changes in delamination damage area for different energy, so the residual compressive performance kept almost stable.

Low-velocity impact response of wood-strand sandwich panels and their components

Holzforschung ◽  
2018 ◽  
Vol 72 (8) ◽  
pp. 681-689 ◽  
Author(s):  
Mostafa Mohammadabadi ◽  
Vikram Yadama ◽  
LiHong Yao ◽  
Debes Bhattacharyya
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Failure Modes ◽  
Sandwich Panels ◽  
Low Velocity Impact ◽  
Insulation Material ◽  
Low Velocity ◽  
Velocity Impact ◽  
Section Modulus ◽  
The Impact

AbstractProfiled hollow core sandwich panels (SPs) and their components (outer layers and core) were manufactured with ponderosa and lodgepole pine wood strands to determine the effects of low-velocity impact forces and to observe their energy absorption (EA) capacities and failure modes. An instrumented drop weight impact system was applied and the tests were performed by releasing the impact head from 500 mm for all the specimens while the impactors (IMPs) were equipped with hemispherical and flat head cylindrical heads. SPs with cavities filled with a rigid foam insulation material (SPfoam) were also tested to understand the change in EA behavior and failure mode. Failure modes induced by both IMPs to SPs were found to be splitting, perforating, penetrating, core crushing and debonding between the core and the outer layers. SPfoams absorbed 26% more energy than unfilled SPs. SPfoams with urethane foam suffer less severe failure modes than SPs. SPs in a ridge-loading configuration absorbed more impact energy than those in a valley-loading configuration, especially when impacted by a hemispherical IMP. Based on the results, it is evident that sandwich structure is more efficient than a solid panel concerning impact energy absorption, primarily due to a larger elastic section modulus of the core’s corrugated geometry.

Impact Energy for the First Crack of Reinforced Concrete with Partial Replacements of Sand by Fine Crumb Rubber

2013 ◽  
Vol 701 ◽  
pp. 286-290 ◽  
Author(s):  
Mustafa Maher Al-Tayeb ◽  
B.H. Abu Bakar ◽  
Hanafi Ismail ◽  
Hazizan Md Akil
Keyword(s):  
Reinforced Concrete ◽  
Impact Energy ◽  
Impact Loading ◽  
Crumb Rubber ◽  
Low Velocity Impact ◽  
Moist Air ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

Effects of partial replacements of sand by waste fine crumb rubber on the performance of reinforced concrete under low velocity impact loading were investigated. Specimens were prepared for 5%, 10% and 20 % replacements by volume of sand. All specimens were cured in moist air for 90 days. For each case, six beams of 100 mm ×100 mm × 500mm were subjected to 5.15 kg hammer from 900mm height. The number of blows of the hammer required to induce the first visible crack of the beam were recorded. The results are presented in terms of impact energy required for the first crack. The fine crumb rubbers increased the impact energy for first crack.

Analysis on Low Velocity Impact Damage and Compressive Residual Strength of Composite Laminates

2014 ◽  
Vol 566 ◽  
pp. 463-467
Author(s):  
Pu Xue ◽  
H.H. Chen ◽  
W. Guo
Keyword(s):  
Experimental Data ◽  
Residual Strength ◽  
Composite Laminates ◽  
Damage Mechanics ◽  
Impact Damage ◽  
Numerical Results ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

This paper studies the impact damage under low velocity impact for composite laminates based on a nonlinear progressive damage model. Damage evolution is described by the framework of the continuum damage mechanics. The real impact damage status of composite laminates has been used to analyze the residual compressive strength instead of assumptions on damage area after impact. The validity of the methodologies has been demonstrated by comparing the numerical results with the experimental data available in literature. The delamination area has an error of 11.3%. The errors of residual strength and compressive displacement are 8.9% and 15%, which indicate that the numerical results matched well with the experimental data.

Failure Analysis of CCF300/5428 Laminates under Low Velocity Impact Based on Properties of Advanced Composite Material

2013 ◽  
Vol 387 ◽  
pp. 185-188
Author(s):  
Jian Yu Zhang ◽  
Ming Li ◽  
Li Bin Zhao ◽  
Bin Jun Fei
Keyword(s):  
Failure Analysis ◽  
Composite Laminates ◽  
Damage Model ◽  
Failure Criteria ◽  
Low Velocity Impact ◽  
Material System ◽  
Low Velocity ◽  
3D Fem ◽  
Velocity Impact ◽  
The Impact

A progressive damage model (PDM) composed by 3D FEM, Hashin and Ye failure criteria and Changs degradation rules was established to deeply understand the failure of a new material system CCF300/5428 under low velocity impact. User defined subroutines were developed and embedded into the general FEA software package to carry out the failure analysis. Numerical simulations provide more information about the failure of composite laminates under low velocity impact, including initial damage status, damage propagation and final failure status. The history of the impact point displacement and various damage patterns were detailed studied.

scholarly journals Low Velocity Impact Assessment of a Carbon Fiber Bicycle Wheel

2021 ◽  
Author(s):  
Karmanya Ratra
Keyword(s):  
Carbon Fiber ◽  
Energy Absorption ◽  
Impact Energy ◽  
Damage Evolution ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Test Protocol ◽  
Velocity Impact ◽  
The Impact

Carbon fiber bicycle wheels were tested under low velocity impact to monitor the damage evolution of the impact event. A wheel model designed by KQS Inc. (industrial partner) with eight different configurations, including spoke tension, number of spokes, and location of impact on the rim were investigated. IR thermography combined with PCA was used to monitor the damage during impact. Results showed that wheels in line with spokes had 16% higher impact energy absorption compared to those impacted in between spokes on average (58.9 J vs 70.2 J). The 20 spoked wheels had a slightly higher (6%) impact energy absorption than the 24 spoked wheels. The added stiffness due to the extra spokes reduced the impact energy absorption of rim. Wheels with higher spoke tension also had slightly improved impact energy absorption (4%). The test protocol established in this study provides a good understanding of the wheel’s impact damage evolution.

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