scholarly journals Numerička analiza dinamičkog ponašanja kompozitnog saćastog panela ispunjenog cevčicama pod dejstvom udarnog opterećenja male brzine u ravni panela

2021 ◽  
Vol 49 (4) ◽  
pp. 969-976
Author(s):  
Younes Djemaoune ◽  
Branimir Krstić ◽  
Boško Rašuo ◽  
Stefan Rašić ◽  
Daniel Radulović ◽  
...  
Keyword(s):  
Model Simulation ◽  
Numerical Study ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Explicit Finite Element ◽  
Impact Performance ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Plane Direction ◽  
The Impact

Honeycomb sandwich structures, composed of many regularly arranged hexagonal cores and two skins, show excellent impact performance due to strong energy absorption capability under impact loads. In this paper, a numerical study of low velocity impact on honeycomb sandwich panels filled with circular tubes in the in-plane direction was performed. To calibrate the numerical model, simulation results in the out-of-plane direction are compared with the experimental ones. The numerical modelling of the drop weight test was carried out using the nonlinear explicit finite element code Abaqus/Explicit. The impact responses are presented as the contact force between the impactor and the panel versus the time. It was concluded that the filled honeycomb panel absorbs the same amount of impact energy in a shorter time than an empty one. In addition, the deflections of the front and back face-sheets are investigated. The panel degradation and the stress distribution during the crushing are also discussed.

Low-velocity impact properties and finite element analysis of syntactic foam reinforced by warp-knitted spacer fabric

2016 ◽  
Vol 87 (16) ◽  
pp. 1938-1952 ◽  
Author(s):  
Chao Zhi ◽  
Hairu Long ◽  
Fengxin Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Syntactic Foam ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Element Analysis ◽  
Velocity Impact ◽  
Impact Performance ◽  
Spacer Fabric ◽  
The Impact

The aim of this research was to investigate the low-velocity impact properties of syntactic foam reinforced by warp-knitted spacer fabric (SF-WKSF). In order to discuss the effect of warp-knitted spacer fabric (WKSF) and hollow glass microballoon parameters on the impact performance of composites, eight different kinds of SF-WKSF samples were fabricated, including different WKSF surface layer structures, different spacer yarn diameters and inclination-angles, different microballoon types and contents. The low-velocity impact tests were carried out on an INSTRON 9250 HV drop-weight impact tester and the impact resistances of SF-WKSF were analyzed; it is indicated that most SF-WKSF specimens show higher peak impact force and major damage energy compared to neat syntactic foam. The results also demonstrate that the surface layer structure, inclination-angle of the spacer yarn and the volume fraction and type of microballoon have a significant influence on the low-impact performance of SF-WKSF. In addition, a finite element analysis finished with ANSYS/LS-DYNA and LS-PrePost was used to simulate the impact behaviors of SF-WKSF. The results of the finite element analysis are in agreement with the experimental results.

scholarly journals Low Velocity Impact Assessment Of Flax And Kevlar-Flax Fibre Reinforced Polymer Laminates Using Experimental and Numerical Methods

2021 ◽  
Author(s):  
Benedict Lawrence Sy
Keyword(s):  
Impact Toughness ◽  
Composite Laminates ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Performance ◽  
Fibre Reinforced Polymer ◽  
The Cross ◽  
The Impact ◽  
Polymer Laminates

Flax/epoxy composite laminates were tested under low velocity impact loading, using passive Infra-Red thermography to monitor the damage evolution during the impact event. Two configurations were tested: unidirectional ([08F]S) and cross-ply ([(0/90)4F]S). The unidirectional laminate exhibited poor and brittle impact response. Conversely, the cross-ply laminate showed better impact performance with its energy penetration threshold three times higher than the unidirectional. Its impact toughness was also 2.5 times higher. Additional tests were conducted to evaluate the effect of hybridization with Kevlar®49. Test results showed significant improvement on the impact performance of the unidirectional flax/epoxy laminate. Hybridization increased its energy penetration threshold three times and impact toughness five times. Conversely, it reduced the penetration threshold of the cross-ply flax/epoxy laminate by 10%; however, it more than doubled the impact toughness. The impact toughness the Kevlar-Flax/epoxy laminates were slightly higher than those of aluminum and CFRP’s, making them sustainable alternatives for impact applications.

Numerical Simulation of Low Velocity Impact on Pin-Reinforced Foam Core Sandwich Panel

2017 ◽  
Vol 742 ◽  
pp. 673-680
Author(s):  
M. Adli Dimassi ◽  
Axel S. Herrmann
Keyword(s):  
Sandwich Structures ◽  
Element Model ◽  
Low Velocity Impact ◽  
Foam Core ◽  
Low Velocity ◽  
Industrial Sectors ◽  
Out Of Plane ◽  
Scale Modelling ◽  
Cohesive Zone Elements ◽  
The Impact

The use of sandwich structures is well established in industrial sectors where high stiffness and strength combined with lightweight are required, like in marine, wind turbine and railway applications. However, the vulnerability of sandwich structures to low-velocity impacts limits its use in primary aircraft structures. Pin reinforcement of the foam core enhances the out-of-plane properties and the damage tolerance of the foam core. In this paper, a finite element model is proposed to predict the impact behaviour of pin-reinforced sandwich structure. An approach based on the building block approach was used to develop the model. Multi-scale modelling in the impact region that considers the delamination of the face sheet using cohesive zone elements was employed to increase the accuracy of the simulation. Impact tests were performed to validate the numerical model. A good agreement between numerical and experimental results in terms of contact-force displacement history and failure mode was found.

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.

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.

Impact response of nanoparticle reinforced 3D woven spacer/epoxy composites at cryogenic temperatures

2021 ◽  
pp. 002199832110370
Author(s):  
Ferhat Yıldırım ◽  
Ahmet Caner Tatar ◽  
Volkan Eskizeybek ◽  
Ahmet Avcı ◽  
Mustafa Aydın
Keyword(s):  
Composite Structures ◽  
Impact Resistance ◽  
Low Velocity Impact ◽  
Woven Composites ◽  
Cryogenic Temperatures ◽  
Low Velocity ◽  
Impact Performance ◽  
Fiber Reinforced Polymer Composites ◽  
3D Woven Composites ◽  
The Impact

Fiber-reinforced polymer composites serving in harsh conditions must maintain their performance during their entire service. The cryogenic impact is one of the most unpredictable loading types, leading to catastrophic failures of composite structures. This study aims to examine the low-velocity impact (LVI) performance of 3D woven spacer glass-epoxy composite experimentally under cryogenic temperatures. LVI tests were conducted under various temperatures ranging from room temperature (RT) to −196°C. Experimental results reveal that the 3D composites gradually absorbed higher impact energies with decreasing temperature. Besides, the effect of multi-walled carbon nanotube and SiO2 nanofiller reinforcements of the matrix on the impact performance and the damage characteristics were further assessed. Nanofiller modification enhanced the impact resistance up to 30%, especially at RT. However, the nanofiller efficiency declined with decreasing temperature. The apparent damages were visually examined by scanning electron microscopy to address the damage formation. Significant outcomes have been achieved with the nanofiller modification regarding the new usage areas of 3D woven composites.

Characterisation of the impact induced damage in composites by cross-comparison among experimental non-destructive evaluation techniques and numerical simulations

2016 ◽  
Vol 231 (16) ◽  
pp. 3077-3090 ◽  
Author(s):  
A Riccio ◽  
S Saputo ◽  
A Sellitto ◽  
V Lopresto
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Composite Plates ◽  
Matrix Cracking ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Premature Failure ◽  
Explicit Finite Element ◽  
The Impact ◽  
Non Destructive

Composite fibre-reinforced materials, under low velocity impacts, can experience simultaneous interacting failure phenomena, such as intra-laminar damage, fibre breakage and matrix cracking, and inter-laminar damage such as delaminations. These failure mechanisms are usually the subject of extensive investigations because they can cause a significant reduction in strength of composites structures leading to premature failure. In the present work, composite plates under low velocity impact are investigated. Experimental data, such as experimental curves and images from non-destructive inspections, are used to characterise the low velocity impacts-induced damage in conjunction with a non-linear explicit Finite element numerical model. The adopted numerical model, implemented in the FE code (Abaqus/Explicit) by a user-defined material subroutine (VUMAT), has been demonstrated to be very effective in predicting the damage onset and evolution and, in general, able to correctly integrate the experimental data by providing useful information about the impact damage localisation and evolution.

Low Velocity Impact Induced Delamination Control Using MFC Actuator

2012 ◽  
Vol 165 ◽  
pp. 346-351 ◽  
Author(s):  
Mohamed Shaik Dawood ◽  
L. Iannucci ◽  
E. Greenhalgh ◽  
Ahmad Kamal Ariffin
Keyword(s):  
Numerical Study ◽  
Damage Model ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Explicit Finite Element ◽  
Velocity Impact ◽  
Energy Impact ◽  
Piezoelectric Effects ◽  
Near Future ◽  
Potential Use

The potential use of MFC actuator as a tool for reducing low velocity impact induced delamination has been investigated using LS-DYNA explicit finite element code. An induced strain piezoelectric actuation model was implemented into LS-DYNA through its user defined material subroutine to simulate the piezoelectric effects while a cohesive based damage model was used to predict delamination. The numerical study confirmed that delamination could be reduced but the MFC required very high actuation voltages even in the case of very low energy impact which is not practically achievable with the existing actuator. Assuming powerful actuators are not something impossible in near future, this study provide useful information for advancing composite impact investigation using piezoelectric actuator as an integrated tool for improving its impact tolerance.

Low-velocity impact behaviour of titanium honeycomb sandwich structures

2017 ◽  
Vol 20 (8) ◽  
pp. 1009-1027 ◽  
Author(s):  
Zonghong Xie ◽  
Wei Zhao ◽  
Xinnian Wang ◽  
Jiutao Hang ◽  
Xishan Yue ◽  
...  
Keyword(s):  
Contact Force ◽  
Sandwich Structures ◽  
Impact Damage ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Honeycomb Sandwich ◽  
The Impact ◽  
Maximum Contact ◽  
Positive Effect

Titanium honeycomb sandwich structures are gradually used in newly developed aircrafts in China. In this study, low-velocity impact tests on the titanium honeycomb sandwich structures were carried out to obtain the impact dynamic response and investigate the typical impact damage modes and parameters including the depths and diameters of the facesheet indentation and the core crushing region. The test results showed that the maximum contact force, the diameter and depth of the indentation had strong positive correlations to the impact energy. Numerical analysis was also conducted to study the low-velocity impact behaviour of the titanium honeycomb sandwich structures by using parametric finite element models that contained all the geometric and the structural details of the titanium honeycomb cores. The numerical results successfully captured the typical low-velocity impact damage modes of the titanium sandwich structures, similar to those observed in the tests. The predicted impact dynamic response also agreed very well with the test data. By using the validated finite element models, a parameter sensitivity study on the effects of the structural parameters on the low-velocity impact damage behaviour of the titanium sandwich structures was conducted. The parametric analysis results showed that the impactor diameter, the facesheet thickness and the core cell wall thickness had positive effect on the maximum contact force, and negative effect on the indentation depth, while the height of the honeycomb core had positive effect on the contact force, but little influence on the indentation depth.

scholarly journals The Impact Characteristics of Fabric Reinforced Hybrid Composites

2017 ◽  
Vol 54 (2) ◽  
pp. 286-290 ◽  
Author(s):  
Marina Bunea ◽  
Radu Bosoanca ◽  
Cristian Eni ◽  
Nicoleta Cristache ◽  
Victorita Stefanescu
Keyword(s):  
Hybrid Materials ◽  
Hybrid Composites ◽  
Low Velocity Impact ◽  
Glass Fabric ◽  
Impact Behavior ◽  
Low Velocity ◽  
Impact Performance ◽  
Hybrid Laminates ◽  
Impact Characteristics ◽  
The Impact

In this research, the impact behavior of hybrid composite materials subjected to low-velocity impact using the drop-weight installation was investigated. For this study were manufactured eight hybrid materials. All the materials were tested to 90J impact energy. The effect of fabric types used in outer layers on impact performance was studied. The impact characteristics of hybrid materials with G1 glass fabric sheets were compared with those of hybrid materials with G2 glass fabric sheets. The damage surfaces of hybrid laminates were examined by visual investigation. The results obtained showed that the using of G2 glass fabric in structure of hybrid materials improved considerable the impact characteristics.

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