Force attenuation capacity of weft-knitted spacer fabric in low-velocity impact

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ryan Rudy ◽  
Wiah Wardiningsih
Keyword(s):  
Impact Force ◽  
Test Method ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Content Type ◽  
Impact Performance ◽  
Spacer Fabric ◽  
Spacer Fabrics ◽  
The Impact ◽  
Peak Impact Force

PurposeThis study aimed to determine the peak impact force and force attenuation capacity of weft-knitted spacer fabrics intended for padding that can be used for human body protection against impact.Design/methodology/approachA total of five weft-knitted spacer fabrics were fabricated with four different diameters of nylon monofilament yarns and one doubled monofilament yarns, respectively. The impact performances of the weft-knitted spacer fabrics were tested using a drop test method with a customized test rig to simulate falling. Impact tests were conducted on single- and multilayered experimental spacer fabrics to investigate the peak impact force and force attenuation capacity.FindingsIt was found that weft-knitted spacer fabric with a coarser or larger diameter of monofilament spacer yarn generated lower impact force and higher force attenuation capacity, thus resulting in better impact performance. Greater force attenuation can be achieved by utilizing a higher number of spacer fabric layers. However, the increase in thickness must be considered with the spacer fabric end use.Originality/valueThis study employed relatively coarse nylon monofilament yarn as spacer yarns to gain knowledge on the impact performance of weft-knitted spacer fabrics compared to warp-knitted spacer fabrics which are more common. The results showed that the diameter of spacer yarn significantly influenced the impact performance of the experimental weft-knitted spacer fabrics. These results could be useful for designing and engineering textile-based impact protectors.

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.

Low-Velocity Impact Properties of Polyurethane Composites Reinforced with Warp-Knit Spacer Fabric

2021 ◽  
Vol 8 (2) ◽  
pp. 38-47
Author(s):  
Si Chen
Keyword(s):  
Absorption Efficiency ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Spacer Fabric ◽  
Energy Absorption Efficiency ◽  
Strain Stress ◽  
Spacer Fabrics ◽  
Polyurethane Composites ◽  
The Impact ◽  
Composite Samples

Eight kinds of polyurethane (PU)-matrix composite samples were prepared by impregnating the warp-knit spacer fabrics with flexible PU foam. An impact test was carried out to investigate the influence of fabric structure parameters on the compression behaviors and energy-absorption efficiency of the composites. By using finite element (FE) analysis and ANSYS software, the unit cell models of the composites were built to simulate the impact responses and get strain-stress curves. Comparison of FE simulation and experimental curves showed good consistency between them.

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.

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.

scholarly journals Effect of Abrasive Concentration on Impact Performance of Abrasive Water Jet Crushing Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Xiaohui Liu ◽  
Ping Tang ◽  
Qi Geng ◽  
Xuebin Wang
Keyword(s):  
Internal Energy ◽  
Impact Force ◽  
Abrasive Particle ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Sph Method ◽  
Impact Performance ◽  
Water Jets ◽  
The Impact ◽  
Peak Impact Force

It has been found that the impact performance of water jets can be changed by its properties, which include pressure, additive, and mode of jet. Thus, an abrasive water jet (AWJ) has been developed as a new method. However, there is little research on the effect of abrasive concentration on the impact performance of abrasive jets. Thus, the SPH method is used to establish an abrasive water jet crushing concrete model to study the effect of abrasive concentration on the impact force, concrete internal energy, abrasive particle distribution, crushing depth, and damage and crushing efficiencies under different concrete compressive strengths and abrasive densities. The results indicate that there is little effect of the abrasive concentration on the peak impact force under different compressive strengths and abrasive densities, while the mean impact force tends to increase linearly with the abrasive concentration. The internal energy of the concrete increases stepwise with the abrasive concentration under different compressive strengths and abrasive densities. The concentration of 10%∼20% is the rapid increasing stage. The crushing depth and damage efficiencies are all maximum at a concentration of 20% under different compressive strengths and abrasive densities. After the concrete was impacted by the water from the water jet, it is divided into rebounding particles and intrusive particles. The more the intrusive particles, the easier the concrete to be crushed and damaged.

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.

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.

A Hierarchical Impact Force Reconstruction Method for Aerospace Composites

2019 ◽  
Vol 812 ◽  
pp. 17-24
Author(s):  
Mario Emanuele de Simone ◽  
Francesco Ciampa ◽  
Michele Meo
Keyword(s):  
Impact Force ◽  
Research Work ◽  
Time History ◽  
Low Velocity Impact ◽  
Reconstruction Method ◽  
Low Velocity ◽  
Force Reconstruction ◽  
Structural Responses ◽  
High Level ◽  
The Impact

This research work presents a hierarchical method able to reconstruct the time history of the impact force on a composite wing stringer-skin panel by using the structural responses measured by a set of surface bonded ultrasonic transducers. Time reversal method was used to identify the impact location by the knowledge of structural responses recorded from a set of excitation points arbitrarily chosen on the plane of the structure. Radial basis function interpolation approach was then used to calculate the transfer function at the impact point and reconstruct the impact force history. Experimental results showed the high level of accuracy of the proposed impact force reconstruction method for a number of low-velocity impact sources and energies.

Multi-layer polymer beam reinforced by graphene platelets on low velocity impact response

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammed Salih Hassan ◽  
Haideer Taleb Shomran ◽  
Abbas Allawi Abbas ◽  
Bashar Dheyaa Hussein Al-Kasob ◽  
Manar Hamid Jasim ◽  
...  
Keyword(s):  
Contact Force ◽  
Separation Of Variables ◽  
Weight Fraction ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Conservation Of Energy ◽  
Content Type ◽  
Graphene Platelets ◽  
The Impact

Purpose The purpose of this paper is to investigate the effect of graphene platelets (GPLs) on the low-speed contact between a mass and surface of a multi-layer polymer beam. Design/methodology/approach This problem is primarily organized by first-order shear deformation beam theory and nonlinear Hertz rule. GPLs are distributed along the beam thickness direction. The Halpin–Tsai micromechanics model is applied for computing the effective Young’s modulus of the GPLs/polymer composites. In the formulation process, the principle of conservation of energy is first used and the histories of results are extracted using the separation of variables and Runge–Kutta method. Findings In comparing the responses with the available data, a good agreement is observed. The effects of the weight fraction and distribution pattern on the impact response of polymer beam reinforced with GPLs are studied. Results show that contact force is increased, contact time and beam recess are decreased with increasing of weight fraction of GPLs. Also, among the different distribution patterns, the contact force depended on value of GPLs at the point of contact. Originality/value The effects of GPLs addition on the multi-layer polymer beam has a novelty in impact problems.

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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