Particular Aspects Concerning Low Velocity Impact on Composite Tubes

2009 ◽  
Vol 417-418 ◽  
pp. 425-428
Author(s):  
Nicolae Constantin ◽  
Ştefan Sorohan ◽  
Mircea Găvan ◽  
Viorel Anghel
Keyword(s):  
Main Parameter ◽  
Impact Force ◽  
Epoxy Composite ◽  
Low Velocity Impact ◽  
Impact Event ◽  
Low Velocity ◽  
Velocity Impact ◽  
Weight Impact ◽  
Composite Pipes ◽  
The Impact

The study had in view various aspects which can arise during the low velocity impact tests made on composite pipes/tubes. It implied numerical simulations, made by ANSYS and LS-DYNA codes, on glass fiber/epoxy composite pipes. The geometry and material characteristics were taken from real pipes, which have been experimentally tested in parallel, using a drop weight impact tower. The main parameter in view was the impact force history, which gives most information upon the impact event and, accordingly, is used by most of researchers for characterizing the damages produced on the impacted body and for assessing the impact installation.

The Low-Velocity Impact Response of Sandwich Panels

2010 ◽  
Vol 168-170 ◽  
pp. 1149-1152
Author(s):  
Xiao Xiong Zha ◽  
Hong Xin Wang
Keyword(s):  
Impact Force ◽  
Energy Levels ◽  
Impact Resistance ◽  
Sandwich Panels ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Weight Impact ◽  
The Impact

The low velocity impact response of sandwich panels at different energy levels has been investigated by conducting drop-weight impact tests using an instrumented falling-weight impact tower. Impact parameters like maximum impact force and the extent of the damage were evaluated and compared for different types of sandwich panels. Finite elements simulations have been undertaken using the LS-DYNA software; the results of FE simulations have a good agreement with the experiments. It shows that, the impact force increased with thickness of face-sheets and foam core, the extent of the damage increased with the impact energy, sandwich panels with steel face sheet has a good impact resistance in comparison with sandwich panel with aluminum face sheets.

Damage Assessment through Impact Force History Recording

2007 ◽  
Vol 347 ◽  
pp. 665-670 ◽  
Author(s):  
Nicolae Constantin ◽  
Mircea Găvan ◽  
Marin Sandu ◽  
Ştefan Sorohan ◽  
Viorel Anghel
Keyword(s):  
Composite Materials ◽  
Damage Assessment ◽  
Impact Force ◽  
Research Work ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Direct Information ◽  
Velocity Impact ◽  
Damage Level ◽  
The Impact

Low velocity impact is a frequent and inevitable in-service event, with higher occurrence in transportation structures. The damages following such an event are more diverse, extended and with more severe consequences in the case of composite materials and structures. The research work presented here concerns fibre reinforced polymeric composites in the forms of plates and pipes. It is continuing an effort meant to allow customers exploiting such structures to have a short cut in monitoring the integrity of this kind of structures. To this end, it is proposed a careful following of the impact force history recording, which can offer valuable and more direct information about the damage level produced under this insidious loading.

Fatigue behavior of graphene nanoplatelets reinforced and unreinforced basalt/epoxy composite pressure vessels subjected to low-velocity impact under internal pressure

2021 ◽  
pp. 002199832110370
Author(s):  
Harun Sepetcioglu ◽  
Necmettin Tarakcioglu
Keyword(s):  
Fatigue Life ◽  
Internal Pressure ◽  
Epoxy Composite ◽  
Fatigue Behavior ◽  
Pressure Vessels ◽  
Graphene Nanoplatelets ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

In this study, the fatigue behavior of 0.25 wt.% graphene nanoplatelets (GnPs) reinforced and unreinforced impact damaged basalt/epoxy composite pressure vessels (CPVs) was investigated. The CPVs were subjected to low-velocity impact (LVI) of 2.5 J, 5 J, 7.5 J, 10 J, 15 J, 20 J, and 25 J under internal pressure of 50 bar (hoop/axial prestresses: 98/49 MPa). Then, to detect fatigue life changes, fatigue tests were performed at load rates of 30% of ultimate hoop stress (σHS), where sweat damage occurred in the basalt/epoxy CPVs under alternating internal pressure. Considering the remaining fatigue life and formation of the damages in the CPVs for all impact energies, to investigate the fatigue behavior and GnPs effects of CPVs subjected to low-velocity impact, an impact value of 5 J was preferred. The 5 J impact damaged CPVs were subjected to fatigue cyclic following ASTM D 2992 at load rates of 20%, 25%, 30%, 35%, and 40% of the σHS. The fatigue life of damaged CPVs was compared by that of undamaged over S-N curves. As the impact energy increased, the impact damage area increased. The increased size of damage reduced the fatigue life of basalt/epoxy CPVs. At the fatigue load rates mentioned above, the GnPs improved the fatigue life of damaged basalt/epoxy CPVs by about 3.5, 3.2, 11.3, 2.4, and 5 times, respectively.

The Effect of Hybridization of the Glass Fiber-Flexible Modified Epoxy and Rigid Epoxy Composite Properties under Low-Velocity Impact

2012 ◽  
Vol 626 ◽  
pp. 255-259
Author(s):  
Siti Nur Liyana Mamauod ◽  
Mohd Hanafiah Abidin ◽  
Ahmad Zafir Romli
Keyword(s):  
Glass Fiber ◽  
Epoxy Composite ◽  
Impact Resistance ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Rigid Polymer ◽  
Brittle Phase ◽  
The Impact ◽  
Modified Epoxy

In the present study, experiment was carried out to investigate the impact properties of flexible and rigid polymer reinforced with E-glass fiber, under low velocity impact. The experimental work includes preparing the cured glassflexible modified epoxy and placed it onto the uncured glass-epoxy composite samples. The experimental results prove that the hybridization improves the impact strength of laminates. The flexibility segments that were introduced into the epoxy system increased the penetration impact resistance value. Hence more impact energy is required to perforate the samples compared to epoxy composite system which is brittle phase.

Behavior of Ferro-Cement Slabs Modified by Polymer under Low Velocity Impact

2014 ◽  
Vol 925 ◽  
pp. 3-7
Author(s):  
Abdulkader Ismail Al-Hadithi ◽  
Khalil Ibrahim Aziz ◽  
Mohammed Tarrad Nawar Al-Dulaimi
Keyword(s):  
Main Parameter ◽  
Small Diameter ◽  
Wire Mesh ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Forces ◽  
Final Failure ◽  
Wire Meshes ◽  
The Impact

Ferro-cement is a type of thin reinforced concrete made of cement-sand mortar mixture with closely spaced of relatively small diameter wire meshes. The main aim of this work was to study investigate the behavior of Ferro-cement slabs under impact loading. A total of 36 Ferro-cement slabs were constructed and tested under low velocity impact, The main parameter considered in the present investigation was number of wire mesh layers, content of (SBR) polymer and height of falling mass (falling velocity). A special testing rig was used to achieve the impact forces using a falling mass (1300 gm steel ball) dropped from (2.5, 1.2 and 0.83 m) height. (500 ×500×50 mm) slabs were used for each test. The polymer (SBR) was used as a ratio by weight of cement of 3%, 5% and 10%. The number of required blows for caused the first crack and final failure was recorded. The results exhibited that the number of blows which were required to make the first crack and failure, increased with increase of polymer content and number of wire mesh layers.

scholarly journals Simulations and Tests of Composite Marine Structures Under Low-Velocity Impact

2021 ◽  
Vol 28 (1) ◽  
pp. 59-71
Author(s):  
Zhaoyi Zhu ◽  
Xiaowen Li ◽  
Qinglin Chen ◽  
Yingqiang Cai ◽  
Yunfeng Xiong
Keyword(s):  
Composite Laminates ◽  
Impact Force ◽  
Low Velocity Impact ◽  
Back Side ◽  
Low Velocity ◽  
Velocity Impact ◽  
Damage Area ◽  
Impact Performance ◽  
Composite Ship ◽  
The Impact

Abstract Due to their excellent performance, composite materials are increasingly used in the marine field. It is of great importance to study the low-velocity impact performance of composite laminates to ensure the operational safety of composite ship structures. Herein, low-velocity drop-weight impact tests were carried out on 12 types of GRP laminates with different layup forms. The impact-induced mechanical response characteristics of the GRP laminates were obtained. Based on the damage model and stiffness degradation criterion of the composite laminates, a low-velocity impact simulation model was proposed by writing a VUMAT subroutine and using the 3D Hashin failure criterion and the cohesive zone model. The fibre failure, matrix failure and interlaminar failure of the composite structures could be determined by this model. The predicted mechanical behaviours of the composite laminates with different layup forms were verified through comparisons with the impact test results, which revealed that the simulation model can well characterise the low-velocity impact process of the composite laminates. According to the damage morphologies of the impact and back sides, the influence of the different layup forms on the low-velocity impact damage of the GRP laminates was summarised. The layup form had great effects on the damage of the composite laminates. Especially, the outer 2‒3 layers play a major role in the damage of the impact and the back side. For the same impact energy, the damage areas are larger for the back side than for the impact side, and there is a corresponding layup form to minimise the damage area. Through analyses of the time response relationships of impact force, impactor displacement, rebound velocity and absorbed energy, a better layup form of GRP laminates was obtained. Among the 12 plates, the maximum impact force, absorbed energy and damage area of the plate P4 are the smallest, and it has better impact resistance than the others, and can be more in line with the requirements of composite ships. It is beneficial to study the low-velocity impact performance of composite ship structures.

scholarly journals Analysis of Impact Behaviour of Sisal-Epoxy Composites under Low Velocity Regime

2021 ◽  
Vol 31 (1) ◽  
pp. 57-63
Author(s):  
Vishwas Mahesh ◽  
Ashutosh Nilabh ◽  
Sharnappa Joladarashi ◽  
Satyabodh M. Kulkarni
Keyword(s):  
Impact Velocity ◽  
Epoxy Composite ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Behaviour ◽  
Damage Initiation ◽  
Structural Applications ◽  
Laminate Thickness ◽  
The Impact

The present study concentrates on development of conceptual proof for sisal reinforced polymer matrix composite for structural applications subjected to low velocity impact using a finite element (FE) approach. The proposed sisal-epoxy composite of various thicknesses of 3.2 mm, 4 mm and 4.8 mm is subjected to different impact velocities of 1 m/s, 2 m/s and 3 m/s ranging in the low velocity impact regime to study the energy absorbed and damage mitigation behaviour of the proposed composite. The consequence of velocity of impact and thickness of laminate on the sisal epoxy composite’s impact behaviour is assessed statistically using Taguchi’s experimental design. Outcome of the present study discloses that the energy absorption increases with increased impact velocity and laminate thickness. However, the statistical study shows that impact velocity is predominant factor affecting the impact response of sisal epoxy composite laminate compared to laminate thickness. The role of matrix and fiber in damage initiation is studied using Hashin criteria and it is found that matrix failure is predominant over the fiber failure.

scholarly journals The Effect of Stacking Sequence and Temperature on the Mechanical and Low Velocity Impact Response of Glass/Epoxy Laminates

2010 ◽  
Vol 19 (4) ◽  
pp. 096369351001900
Author(s):  
Semih Benli ◽  
Onur Sayman ◽  
Yusuf Arman
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Composite Laminates ◽  
Epoxy Composite ◽  
Low Velocity Impact ◽  
Stacking Sequence ◽  
Low Velocity ◽  
Velocity Impact ◽  
Thermal Residual Stresses ◽  
The Impact

This paper demonstrates both low velocity impact and mechanical test results of glass/epoxy composites at room and high temperatures. Square specimens of glass/epoxy composite laminates with lay-ups [0/0/90]s, [90/0/0]s, [0/90/45]s were subjected to low velocity impact energy range of 4 J to 22 J using an impact test machine at temperatures of 20°C, 50°C and 90°C. Load-deflection and energy profile diagrams were plotted for each stacking sequence and temperature. After impact, a high-intensity light was used to measure the projected delamination areas in the impacted glass/epoxy composite laminates. In order to investigate effects of temperature on mechanical properties and impact resistance, mechanical tests were also performed using unidirectional glass/epoxy composite plates composed of eight plies produced according to ASTM Standards. In addition, to understand the contribution of thermal residual stresses occurring during and after manufacturing of composite laminates on impact-induced delamination, SX and SY stresses in the composite laminates at 20, 50 and 90°C were determined by using ANSYS software. It can be concluded from this study that temperature has significant effects on the impact behaviour and mechanical properties of glass fibre-reinforced epoxy composite laminates. Besides, an increase in temperature decreases both the delamination area and the contribution of thermal residual stresses on delamination under the same impact loading.

Impact Resistance of Filament Wound Composite Pipes: A Parametric Study

2014 ◽  
Author(s):  
Abul Fazal M. Arif ◽  
M. Haris Malik ◽  
A. S. Al-Omari
Keyword(s):  
Parametric Study ◽  
Low Velocity Impact ◽  
Design Parameters ◽  
Low Velocity ◽  
Velocity Impact ◽  
Filament Wound ◽  
Filament Wound Composite ◽  
Composite Pipes ◽  
The Impact ◽  
Wound Composite

Filament wound composite pipes are being used in more and more applications. However, the impact behavior of these pipes is of particular importance in many applications. The sudden failure of these pipes under low velocity impact loads can be dangerous especially when the medium inside the pipe is hazardous or toxic in nature. The impact response of a composite laminate depends upon various factors such as thickness, stacking sequence and number of layers. The primary focus of this paper is parametric study of low velocity impact damage of CFRP and GFRP pipes under varying design parameters using finite element analysis. The simulation results are then used along with the ANN (Artificial Neural Networks) to fit a function to estimate the amount of absorbed energy.

Effect of Core Thicknesses on Impact Performance of Thermoplastic Honeycomb Core Sandwich Structure under Low-Velocity Impact Loading

2011 ◽  
Vol 471-472 ◽  
pp. 461-465
Author(s):  
Nurashikin Sawal ◽  
Md Akil Hazizan
Keyword(s):  
Impact Force ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Face Sheet ◽  
Low Velocity ◽  
Velocity Impact ◽  
Damage Area ◽  
Impact Performance ◽  
Core Thickness ◽  
The Impact

Low-velocity impact test on sandwich panels composed of aluminum face sheets and thermoplastic honeycomb cores have been performed to characterize the impact performance as a function of core thickness and drop heights. Impact parameters like maximum impact force, impact energy and impact damage area were evaluated and compared. Consequent damages were inspected visually on the impact surface as well as the rear surface. The experimental results found that panels with thicker core exhibited higher impact force than thinner core counterparts, allowing the panel to absorbed more energy. Higher degree of impact damage can be observed at elevated drop heights as most of the damage took the form of local core crushing, face sheet buckling and debonding between the face sheet and core,. Resulting damage area were different according to the core thickness as thicker core prone to absorbed more energy that lead to more damage propagation.

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