Experimental study of the impact behavior of laminated composites stricken by sharp impactors

2012 ◽  
Vol 19 (3) ◽  
pp. 307-313 ◽  
Author(s):  
Mesut Uyaner ◽  
Memduh Kara
Keyword(s):  
Contact Force ◽  
Impact Behavior ◽  
Test Machine ◽  
Absorbed Energy ◽  
Nominal Thickness ◽  
Weight Test ◽  
Force Time ◽  
Drop Weight Test ◽  
The Impact ◽  
Composite Samples

AbstractIn this study, the influence of the impactor shape on the dynamic response of E-glass/epoxy laminates was investigated. Composite samples were impacted using steel 90° and 120° conical, 24 mm and 12 mm in diameter hemispherical, pyramidal impactors via a specially developed drop weight test machine. The impact tests were performed at impactor mass (20 kg) for impact velocity (2.5 m/s). Plate specimens consisting of 18 plies for tests (180×50 mm) with a nominal thickness (7 mm) were used. Contact force-time and contact force-deflection data obtained from the experiments were interpreted. It was found that the contact force was smaller in the 90° conical impactor while it was bigger in the 24 mm hemispherical one. Absorbed energies were also investigated. The absorbed energy obtained for pyramidal impactor was greater than that of the others. Furthermore, overall damage areas caused by the impactor were evaluated.

Effect of specimen size and ball size on breakage throughput in the drop-weight test

2018 ◽  
Vol 233 (2) ◽  
pp. 202-210 ◽  
Author(s):  
Mehdi Akhondizadeh ◽  
Masoud Rezaeizadeh
Keyword(s):  
Impact Energy ◽  
Specimen Size ◽  
Test Machine ◽  
Ball Size ◽  
Drop Weight ◽  
Weight Test ◽  
Drop Weight Test ◽  
Steel Balls ◽  
The Impact ◽  
Specific Impact

Effects of specimen size and ball size on the breakage throughput under the impact loading are investigated using a drop-weight test machine. Samples are square-shaped building stones ranging 20–60 mm in width and 22–256 g in mass. They include granite, marble, and two types of travertine with the thickness of 15 mm. The impact energies, up to 160 J, are achieved by falling balls in a drop-weight test machine. Several steel balls with the diameter of 60, 84, 96, and 120 mm have been used as an impactor. The ball size is a parameter whose effect on the breakage throughput is investigated here. Results show that the larger specimens have better breakage than the smaller ones at the same specific impact energy. It is also indicated that, at constant specific impact energy, the smaller balls behave more efficiently than the larger balls.

scholarly journals Evaluation of Impact Resistance for Derailment Containment Provision Using Drop Weight Test

2020 ◽  
Vol 20 (5) ◽  
pp. 185-194
Author(s):  
NamHyuk Kim ◽  
YunSuk Kang ◽  
HyunUng Bae ◽  
KyungJu Kim ◽  
NamHyoung Lim
Keyword(s):  
High Speed ◽  
Impact Resistance ◽  
Impact Behavior ◽  
Human Errors ◽  
Railway Bridges ◽  
Drop Weight ◽  
Weight Test ◽  
Drop Weight Test ◽  
Protective Performance ◽  
The Impact

In Korea, to prepare for unexpected accidents caused by human errors and natural disasters that cannot be completely prevented, a protective wall (a type of side-structure) against derailed trains has been installed on high-speed railway bridges as one of the physical measures to mitigate the associated damage. However, taking the geometric aspects of a domestic railway bridge's super structure into consideration, such a protective wall is not appropriate, and the corresponding protective performance does not provide adequate security. Hence, a protective wall named Derailment Containment Provision (DCP) was newly developed and installed in the track gauge. In this study, to evaluate the impact resistance of the newly developed DCP, a drop weight experiment was conducted, and the impact behavior corresponding to a specific impact energy was analyzed.

scholarly journals Effects of temperature and impactor nose diameter on the impact behavior of PA6 and PP thermoplastic composites

2018 ◽  
Vol 51 (1) ◽  
pp. 64-74 ◽  
Author(s):  
Akar Dogan ◽  
Yusuf Arman
Keyword(s):  
Load Capacity ◽  
Testing Machine ◽  
Polyamide 6 ◽  
Impact Testing ◽  
Impact Behavior ◽  
Thermoplastic Composites ◽  
Test Machine ◽  
Effects Of Temperature ◽  
Impact Energies ◽  
The Impact

In this study, the effects of temperature and impactor nose diameter on the impact behavior of woven glass-reinforced polyamide 6 (PA6) and polypropylene (PP) thermoplastic composites were investigated experimentally. Impact energies are chosen as 10, 30, 50, 70, 90, 110, 130, and 170 J. The thickness of composite materials is 4 mm. Impact tests were performed using a drop weight impact testing machine, CEAST-Fractovis Plus, and the load capacity of test machine is 22 kN. Hemispherical impactor nose diameter of 12, 7, and 20 mm were used as an impactor. The tests are conducted at room temperature (20°C and 75°C). As a result, the PP composites of the same thickness absorbed more energy than PA6 composites. The amount of absorbed energy of PP and PA6 composites decreased with temperature.

Impact Testing of Concrete Using a Drop-Weight Impact Machine

2015 ◽  
Vol 1106 ◽  
pp. 225-228 ◽  
Author(s):  
Stanislav Rehacek ◽  
Petr Hunka ◽  
David Citek ◽  
Jiri Kolisko ◽  
Ivo Simunek
Keyword(s):  
Positive Impact ◽  
Impact Load ◽  
Impact Testing ◽  
Impact Loads ◽  
Test Machine ◽  
Impact Machine ◽  
Drop Weight ◽  
Weight Test ◽  
Load Tests ◽  
Drop Weight Test

Fibre-reinforced composite materials are becoming important in many areas of technological application. In addition to the static load, such structures may be stressed with short-term dynamic loads or even dynamic impact loads during their lifespan. Impact loading of structural components produces a complex process, where both the characteristics of the design itself and the material parameters influence the resultant behavior. It is clear that fibre reinforced concrete has a positive impact on increasing of the resistance to impact loads. Results of two different impact load tests carried out on drop-weight test machine are presented in this report.

Development and characterization of structural adhesives for aerospace industry with alumina nanoparticles under shear and thermo-mechanical impact loads

2019 ◽  
Vol 234 (2) ◽  
pp. 490-507 ◽  
Author(s):  
UA Khashaba ◽  
Ramzi Othman ◽  
Ismael MR Najjar
Keyword(s):  
Contact Force ◽  
Bending Stiffness ◽  
Alumina Nanoparticles ◽  
Absorbed Energy ◽  
Impact Machine ◽  
Impact Properties ◽  
Weight Percentage ◽  
Mechanical Impact ◽  
Impact Bending ◽  
The Impact

The present work aims to improve the mechanical properties of Epocast 50-A1/946 epoxy via incorporation of alumina nanoparticles using an ultrasonic agitation method. The optimum weight percentage of alumina nanoparticles was determined based on the improvement in the shear and impact properties of the nanocomposites at room temperature and 50 ℃. Accordingly, neat epoxy panels and nanocomposite panels with 0.5, 1.0, 1.5, and 2.0 wt% alumina nanoparticles were fabricated. The shear and thermo-mechanical impact properties of the panels were measured using an instrumented drop-weight impact machine and an Iosipescu shear test fixture, respectively, according to ASTMs D5379 and D7136. The maximum improvement in shear strength and modulus was 10.9% and 8.1%, respectively, for the nanocomposites containing 1.0 and 1.5 wt% alumina nanoparticles. The predicted shear moduli of the nanocomposites agreed well with the measured values with a maximum error of 6.52%. The optimal performance of impact properties was achieved by incorporating 1.0 wt% of alumina nanoparticles. Namely, the maximum impact-bending stiffness, contact force, and absorbed energy were increased by 12.9%, 13.0%, and 23.4%, respectively. The test temperature of 50 ℃ was found to have a negative effect on the impact-bending stiffness and the maximum contact force. On the other hand, the absorbed energy was increased up to 12.1%.

scholarly journals Experimental Investigation on Relations Between Impact Resistance and Tensile Properties of Cement-Based Materials Reinforced by Polyvinyl Alcohol Fibers

2019 ◽  
Vol 9 (20) ◽  
pp. 4434
Author(s):  
Ju Zhang ◽  
Pucun Bai ◽  
Changwang Yan ◽  
Shuguang Liu ◽  
Xiaoxiao Wang
Keyword(s):  
Polyvinyl Alcohol ◽  
Tensile Properties ◽  
Impact Load ◽  
Impact Resistance ◽  
Crater Diameter ◽  
Cement Based Materials ◽  
Weight Test ◽  
Ultimate Failure ◽  
Drop Weight Test ◽  
The Impact

Cement-based material is brittle and is easily damaged by an impact load with a few blows. The purpose of this paper is to study the relations between the impact resistance and tensile properties of cement-based materials reinforced by polyvinyl alcohol fiber (PVA-FRCM). A drop-weight test and uniaxial tension test were performed. The relations were studied based on the experimental results, including the relation between the blow number and the tensile stress at the first visible cracking (σc) and the relation between the blow number and the tensile strain at the ultimate failure (εf). Results showed that the blow number for the first visible crack for disc impact specimens increases obviously with the increase of σc of slab specimens. The crater diameter and blow number for ultimate failure of the disc specimens increase with the increase of εf of slab specimens. For the PVA-FRCM specimens with larger σc and εf, much more blows are needed to cause both the first visible crack and ultimate failure. Polyvinyl alcohol fibers can reinforce impact resistance and tensile properties of cement-based materials.

Impact Behavior of Cracked Plate Repaired with Composite and FML Patches

2008 ◽  
Vol 47-50 ◽  
pp. 612-616 ◽  
Author(s):  
Mehdi Sadeghinia ◽  
Seyyed Mohammad Reza Khalili ◽  
R. Ghadjar
Keyword(s):  
Crack Length ◽  
Charpy Impact ◽  
Thin Layers ◽  
Impact Behavior ◽  
Single Edge ◽  
Absorbed Energy ◽  
Cracked Plate ◽  
Cracked Plates ◽  
Single Side ◽  
The Impact

In this paper, the impact behavior of repaired cracked plates was investigated experimentally. single edge cracked aluminum plate having crack length to width ratios of 0.1, 0.3 and 0.5 was repaired with four different patch configurations namely: 3 layer GRP, 5 layer GRP patch, 2/1 FML patch and 3/2 FML patches tested in Charpy impact and the energy absorbed by specimens were compared together and compared with the unrepaired cracked plate. FML patches were made of thin layers of glass/epoxy composites of 0.2 mm thickness with phosphor bronze sheets of 0.2 mm thickness. The patching was single side. The composite and FML patching was more effective in repairing the specimens with greater crack length. Placing 3 GRP and 5 GRP patches increased the absorbed energy by only 3 to 4 joules respectively as compared to unrepaired plate. The use of 2/1 and 3/2 FML patches could increase the absorbed energy two to four times depend on crack length.

Impact Resistance of Thin-Walled Shell Structures

2014 ◽  
Vol 617 ◽  
pp. 96-99
Author(s):  
Stanislav Řeháček ◽  
Petr Huňka ◽  
David Čítek ◽  
Jiří Kolísko ◽  
Ivo Šimúnek
Keyword(s):  
Positive Impact ◽  
Impact Load ◽  
Impact Resistance ◽  
Shell Structures ◽  
Impact Loads ◽  
Test Machine ◽  
Weight Test ◽  
Load Tests ◽  
Thin Walled ◽  
Drop Weight Test

Fibre-reinforced composite materials are becoming important in many areas of technological application. In addition to the static load, such structures may be stressed with short-term dynamic loads or even dynamic impact loads during their lifespan. Dynamic effects can be significant especially for thin-walled shell structures and barrier constructions. Impact loading of construction components produces a complex process, where both the characteristics of the design itself and the material parameters influence the resultant behavior. It is clear that reinforced concrete with fibers has a positive impact on increasing the resistance to impact loads. Results of impact load tests carried out on drop-weight test machine are presented in this paper. The results are supplemented by compression strength test.

scholarly journals Simulation of Delamination Evolution of Slab Ballastless Track under Vertical Impact

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yu Liu ◽  
Qianqi Xu ◽  
Xiaodan Sun ◽  
Guotao Yang ◽  
Guotang Zhao
Keyword(s):  
Contact Force ◽  
Impact Energy ◽  
Zone Model ◽  
Vertical Deformation ◽  
Interfacial Damage ◽  
Absorbed Energy ◽  
Normal Stiffness ◽  
Track Irregularity ◽  
The Impact ◽  
Vertical Impact

During the running of a high-speed train, the wheel may bounce on the rail due to the track irregularity. The wheel bounce could generate a vertical impact, leading to the initiation and expansion of delamination between layers of the track structure. In this paper, the evolution of the interfacial damage and delamination subjected to the vertical impact is simulated using finite element analysis (FEA). In the FEA, a bilinear cohesive zone model (CZM) is adopted to simulate the interface between the track slab and the CA mortar layer. For different levels of impact energy, the contact force, vertical deformation, absorbed energy, area of interfacial damage, and area of delamination are calculated and compared. The effects of the tangential and normal stiffness of the interface on the distribution of interfacial damage and delamination are investigated. The results show that the contact force, vertical deformation, absorbed energy, area of interfacial damage, and area of delamination increase with the increase of the impact energy. The area of interfacial damage in the compression stage is closely related to the tangential stiffness, whereas the area of delamination depends on the normal stiffness. The normal stiffness that gives the largest area of delamination is recommended to be taken as the lower bound of the normal stiffness for both controlling the delamination and preventing an exceedance of the track irregularity limit.

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