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.

Impact Energy for First Crack of Reinforced Concrete with Partial Replacements of Sand by Rubber 1 mm Particle Size

2013 ◽  
Vol 701 ◽  
pp. 261-264 ◽  
Author(s):  
B.H. Abu Bakar ◽  
Mustafa Maher Al-Tayeb ◽  
Hanafi Ismail ◽  
Hazizan M. Akil
Keyword(s):  
Particle Size ◽  
Reinforced Concrete ◽  
Impact Energy ◽  
Crumb Rubber ◽  
Low Velocity Impact ◽  
Moist Air ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact ◽  
Waste Crumb Rubber

Effects of partial replacements of sand by waste crumb rubber 1 mm particle size 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 crack of the beam were recorded. The results are presented in terms of impact energy required for the first crack. The crumb rubbers increased the impact energy for first crack.

Experimental Investigation Into the Effect of Impact Loading on the Response of Metallic Trapezoidal Corrugated Core Sandwich Panels

2018 ◽  
Author(s):  
Haifu Yang ◽  
Yuansheng Cheng ◽  
Pan Zhang ◽  
Jun Liu ◽  
Kai Chen
Keyword(s):  
Dynamic Response ◽  
Impact Energy ◽  
Impact Loading ◽  
Sandwich Panels ◽  
Low Velocity Impact ◽  
Front Face ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Location ◽  
The Impact

Sandwich structures with corrugated cores have attracted a lot of interest from industrial and academic fields due to their superior crashworthiness. In this paper, the dynamic response of metallic trapezoidal corrugated core sandwich panels under low-velocity impact loading is studied by conducting drop hammer impact testing. The sandwich panels composed of two thin face skins and trapezoidal corrugated core, were designed and fabricated through folding and laser welding technology. Main attention of present study was placed at the influences of the impact energy, impactor diameter and impact location on the impact force, deformation mechanisms and the permanent deflections of the trapezoidal corrugated core sandwich panels. Results revealed that the impact energy has significant effects on the dynamic response of the sandwich panel, whereas the impact diameter has little effects on it. The deformation mode of the front face sheet differs sharply when the impact location is different. The middle unit cell of corrugated core is compressed to the “M” shape under different low-velocity impact loading.

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).

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.

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.

Effect of Foam Core Density and Facesheet Thickness on the Low Velocity Impact Response of Foam Core Sandwich Composites

2000 ◽  
Author(s):  
M. Motuku ◽  
R. M. Rodgers ◽  
S. Jeelani ◽  
U. K. Vaidya
Keyword(s):  
Impact Energy ◽  
Maximum Load ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Foam Core ◽  
Low Velocity ◽  
Core Density ◽  
Failure Characteristics ◽  
Velocity Impact ◽  
The Impact

Abstract The effect of foam core density and facesheet thickness on the low velocity impact response and damage evolution in homogeneous foam core sandwich composites was studied. The failure characteristics, initiation and evolution of damage as well as the effect of impact energy were investigated. A Dynatup 8210 Impact Test Machine was utilized to conduct the low-velocity impact tests. Characterization of the impact response was performed by comparing the impact load histories, impact plots and failure characteristics. Fractography analysis was conducted through the use of scanning electron microscopy (SEM) and optical microscopy. Three types of foam cores with different densities, namely Airlite B12.5, Rohacell IG-71R63 and Airex R63.5 foam cores, were used to study the effect of core density. Considering four groups of facesheets made of different layers of cross-ply carbon prepregs performed the effect of facesheet thickness. For all the facesheet thicknesses (0.011-0.894-cm thick) and impact energy (11-40 J) range considered in this study, the maximum load (Pm), deflection-at-maximum load (δm) and time-to-maximum load (tm) exhibited strong influence or dependence on the type of foam core as opposed to the facesheet thickness. The energy-to-maximum load (Em), total energy absorbed (Et) and total energy-to-impact energy (Et/Eimp) ratio became less sensitive on the foam core density (or type) with increasing facesheet thickness. A transition point from foam core to facesheet controlled impact behavior as a function of impact energy level was observed. The impact parameters varied either linearly or parabolically with impact energy depending on the impact energy level, type of foam core and facesheet thickness. Excellent repeatability of impact data was generally obtained with increase in foam core density.

Experimental investigation of low velocity impact on textile cellular composite with different energy construction

2018 ◽  
Vol 48 (6) ◽  
pp. 1009-1023 ◽  
Author(s):  
Xiaozhou Gong ◽  
Pengying Pei ◽  
Yu Hu ◽  
Xiaogang Chen
Keyword(s):  
Cell Size ◽  
Impact Energy ◽  
Initial Velocity ◽  
Low Velocity Impact ◽  
Wall Material ◽  
Low Velocity ◽  
Velocity Impact ◽  
Cellular Composite ◽  
Big Cell ◽  
The Impact

Cellular composite, with an array of regular hexagonal cells in the cross section, is a type of textile composites having the advantage of being light weight and energy absorbent over the solid composite materials. However, when it is under the same energy level of low velocity impact with different tup mass and velocity, its behavior is yet unknown. In the experiment, four groups of samples, with twelve geometrical variants have been systematically created for the impact testing. The impact test is running in two categories with one type of low velocity impact with initial velocity of 5.5 m/s by the tup mass of 0.55 kg, and another testing under the similar impact energy but with a lower initial velocity around 2.0 m/s with heavier tup mass of 4.52 kg. The impact energies in the above cases are very similar about 8.5 J, which indicates that the impact energy is the same while the energy construction is different. After the test, it is found that composite with medium cell size has more stable mechanical performances under various exposed impact conditions. It is also concluded that composites with big cell size are much easier to be destroyed under heavier impact tup, therefore, under condition of more critical loading force, it is necessary to find a way to enhance the big cell sized composites’ wall material in order to strengthen their structure performances. The results of this work provide a reference for the researchers who are kneeing to investigate the impact mechanism of textile cellular composites.

Impact Characteristics and Damage Detection of Woven Carbon/Epoxy Laminates for Car Body Structures of a Tilting Train

2006 ◽  
Vol 321-323 ◽  
pp. 942-945 ◽  
Author(s):  
Jae Heon Lee ◽  
Seong Kyun Cheong ◽  
Jung Seok Kim ◽  
K.Y. Eum
Keyword(s):  
Impact Energy ◽  
Low Velocity Impact ◽  
Light Weight ◽  
Laser Technique ◽  
Low Velocity ◽  
Velocity Impact ◽  
Car Body ◽  
Tilting Train ◽  
Impact Characteristics ◽  
The Impact

Recently, the use of composite material to railway vehicles is gradually increasing due to its light weight. The concept of light weight design will be very helpful for the tilting train to travel around a curve at a faster speed because the light weight car body makes the center of gravity lower. The impact characteristics of composite materials should be investigated because the impact property of composites is very important for the design and repair of a tilting train. This paper investigates the low-velocity impact and damage characteristics conducted on woven carbon/epoxy laminates for a tilting train. Low-velocity impact tests were carried out at different energy levels on woven type of laminates using a drop-weight apparatus. The impact-induced delaminations are examined by ultrasonic technique such as C-Scan. Those delaminations are also examined by laser technique such as ESPI (Electronic Speckle Pattern Interferometry). Experimental results show that the type of damage is dependent on the impact energy level and the delamination area becomes larger as the impact energy increases.

scholarly journals The Low Velocity Impact Properties of Pandanus Fiber Composites

2017 ◽  
Vol 895 ◽  
pp. 56-60 ◽  
Author(s):  
Hoo Tien Nicholas Kuan ◽  
Meng Chuen Lee ◽  
Amir Azam Khan ◽  
Marini Sawawi
Keyword(s):  
Impact Loading ◽  
Volume Fraction ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Impact Properties ◽  
Velocity Impact ◽  
Impact Performance ◽  
Biodegradable Composites ◽  
Penetration Tests ◽  
The Impact

The impact properties of biodegradable Pandanus atrocarpus composite laminate is studied. Laminate samples were fabricated using a hot compression molding technique with high-density polyethylene and extracted Pandanus fiber. Pandanus composites were tested under impact loading in order to study their relative impact performance. Under low velocity impact loading, Pandanus fiber laminates offered an excellent resistance to impact penetration. Tests have shown that increasing the volume fraction of Pandanus fiber can enhance the toughness of the composite. The biodegradable composites imply attractive properties that may be accessible for use in engineering sectors.

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