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Article

Xinlei Gao, Tingting Wang and Zhong Cheng

Ultra-high molecular weight polyethylene (UHMWPE) has an excellent performance and application value; however, as a tribological material, its main drawback is its poor…

Abstract

Purpose

Ultra-high molecular weight polyethylene (UHMWPE) has an excellent performance and application value; however, as a tribological material, its main drawback is its poor performance under dry friction, impacting its ability to work in high-speed dry friction conditions. Modification of UHMWPE can be carried out to overcome these issues. A significant number of inorganic materials have been used to modify UHMWPE and provide it with good tribological performance. However, thus far, there has been no systematic investigation into the methodology of modifying UHMWPE. The authors take a quantitative approach to determine the structure tribo-ability relationship and basic principles of screening of inorganic compounds suited to modify UHMWPE.

Design/methodology/approach

The tribological properties of modified UHMWPE using a series of inorganic additives have been qualitatively studied by the authors’ research group previously. In this study, basic quantitative structure tribo-ability relationships (QSTRs) of inorganic additives for modifying UHMWPE were studied to predict tribological properties. A set of 15 inorganic compounds and their tribological data were used to study the predictive capability of QSTR towards inorganic additives properties.

Findings

The results show that the anti-wear and friction-reducing properties of these inorganic compounds correlate with the calculated parameters of entropy and dipole moment. Increased entropy and smaller dipole moment can effectively improve the anti-wear and friction-reducing ability of inorganic compounds as UHMWPE additives. Additives with larger molecular weight, lower hardness and lower melting and boiling points provide good tribological properties for UHMWPE. For inorganic compounds to act as UHMWPE additives, the chemical bond should be less covalent and have more ionic character.

Research limitations/implications

Only 15 inorganic compounds and their tribological data were used to study the predictive capability of QSTR towards inorganic additives properties. If the samples number is more than 30, the other QSTR methodology can be used to study the modified UHMWPE, and the models finding can be more precise.

Practical implications

A QSTR model for modified UHMWPE has been studied systematically. While the results are not more precise and detailed, the model provides a new way to explore the modified UHMWPE characteristics and to reveal new insight into the friction and wear process.

Social implications

Because the method of studying tribological materials is entirely different from others, the authors want to present the works and discuss it with colleagues.

Originality/value

The paper presents a new method to study the modified UHMWPE. A QSTR is used to study the tribology capability of compounds from calculated structure descriptors. This study uses the Hartree–Fock ab initio method to establish a QSTR prediction model to estimate the ability of 15 inorganic compounds to act as anti-wear and friction-reducing additives for UHMWPE.

Details

Industrial Lubrication and Tribology, vol. 70 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

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Article

Mica Grujicic, Jennifer Snipes, S. Ramaswami, Vasudeva Avuthu, Chian-Fong Yen and Bryan Cheeseman

To overcome the problem of inferior through-the-thickness mechanical properties displayed by armor-grade composites based on 2-D reinforcement architectures, armor-grade…

Abstract

Purpose

To overcome the problem of inferior through-the-thickness mechanical properties displayed by armor-grade composites based on 2-D reinforcement architectures, armor-grade composites based on 3D fiber-reinforcement architectures have recently been investigated experimentally.

Design/methodology/approach

The subject of the present work is armor-grade composite materials reinforced using ultra-high-molecular-weight polyethylene fibers and having four (two 2D and two 3D) prototypical architectures, as well as the derivation of the corresponding material models. The effect of the reinforcement architecture is accounted for by constructing the appropriate unit cells (within which the constituent materials and their morphologies are represented explicitly) and subjecting them to a series of virtual mechanical tests. The results obtained are used within a post-processing analysis to derive and parameterize the corresponding homogenized-material models. One of these models (specifically, the one for 0°/90° cross-collimated fiber architecture) was directly validated by comparing its predictions with the experimental counterparts. The other models are validated by examining their physical soundness and details of their predictions. Lastly, the models are integrated as user-material subroutines, and linked with a commercial finite-element package, in order to carry out a transient non-linear dynamics analysis of ballistic transverse impact of armor-grade composite-material panels with different reinforcement architectures.

Findings

It is found that the reinforcement architecture plays a critical role in the overall ballistic limit of the armor panel, as well as in its structural and damage/failure response.

Originality/value

To the authors’ knowledge, the present work is the first reported attempt to assess, computationally, the utility and effectiveness of 3D fiber-reinforcement architectures for ballistic impact applications.

Details

Engineering Computations, vol. 33 no. 3
Type: Research Article
ISSN: 0264-4401

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Article

Xiaocui Xin, Yunxia Wang, Zhaojie Meng, Hao Liu, Yunfeng Yan and Fengyuan Yan

This paper aims to focus on studying the addition of nano-tungsten disulfide (WS2) on fretting wear performance of ultra-high-molecular-weight-polyethylene (UHMWPE).

Abstract

Purpose

This paper aims to focus on studying the addition of nano-tungsten disulfide (WS2) on fretting wear performance of ultra-high-molecular-weight-polyethylene (UHMWPE).

Design/methodology/approach

In this study, the effect of WS2 content on fretting wear performance of UHMWPE was investigated. The fretting wear performance of the UHMWPE and WS2/UHMWPE nanocomposites were evaluated on oscillating reciprocating friction and wear tester. The data of the friction coefficient and the specific wear rate were obtained. The worn surfaces of composites were observed. The transfer film and its component were analyzed.

Findings

With the addition of 0.5% WS2, the friction coefficient and specific wear rate increased. With the content increased to 1% and 1.5%, the friction coefficient and specific wear rate decreased. The lowest friction coefficient and specific wear rate were obtained with the addition of 1.5% nano-WS2. Continuingly increasing content, the friction coefficient and wear rate increased but lower than that of pure UHMWPE.

Research limitations/implications

The research indicated the fretting wear performance related to the content of nano-WS2 with the incorporation of WS2 into UHMWPE.

Practical implications

The result may help to choose the appropriate content.

Originality/value

The main originality of the research is to reveal the fretting behavior of UHMWPE and WS2/UHMWPE nanocomposites. It makes us realize the nano-WS2 had an effect on the fretting wear performance of UHMWPE.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0151/

Details

Industrial Lubrication and Tribology, vol. 73 no. 1
Type: Research Article
ISSN: 0036-8792

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Article

Huseyin Unal, Salih Hakan Yetgin and Fehim Findik

– The purpose of the study was to find the best performance polymer material to be used in railway car bogies.

Abstract

Purpose

The purpose of the study was to find the best performance polymer material to be used in railway car bogies.

Design/methodology/approach

Wear tests and optical and scanning electron microscopy were used.

Findings

The friction coefficients of ultra-high-molecular-weight polyethylene (UHMWPE) and Nylon 6 polymers, as opposed to AISI 4140 steel, reduced with the increment of applied loads. With the increment of sliding speed, the friction coefficient increased in both UHMWPE and Nylon 6 polymers. The specific wear rate of the UHMWPE polymer was determined to be about 10-14 m2/N, whereas the rate of Nylon 6 was determined to be 10-13 m2/N.

Practical implications

The aim of the study was to find the best performance polymer material to be used in railway car bogies.

Originality/value

The friction and wear performance of UHMWPE and Nylon 6 engineering polymers were studied and compared to their AISI 4140 steel counterparts. It is an original work and it is not published in any media.

Details

Industrial Lubrication and Tribology, vol. 66 no. 3
Type: Research Article
ISSN: 0036-8792

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Article

Xiaocui Xin, Yunxia Wang, Zhaojie Meng and Fengyuan Yan

The purpose of this paper is to investigate the fretting wear performance of ultra-high-molecular-weight-polyethene (UHMWPE) with addition of GO and SiO2.

Abstract

Purpose

The purpose of this paper is to investigate the fretting wear performance of ultra-high-molecular-weight-polyethene (UHMWPE) with addition of GO and SiO2.

Design/methodology/approach

In this study, GO were synthesized and SiO2 nanoparticles were grafted onto GO. The effect of nanofiller on fretting wear performance of UHMWPE was investigated.

Findings

The results indicated that GO was successfully synthesized and SiO2 nanoparticles successfully grafted onto GO. Incorporation of GS was beneficial for the reduction in friction and the improvement in wear resistance of UHMWPE. GO was beneficial for reducing friction coefficient, while SiO2 was good for improving wear resistance. There existed a tribological synergistic effect between GO nanosheet and SiO2 nanoparticles.

Research limitations/implications

The hybrids of GS were promising nanofiller for improving the fretting wear performance of UHMWPE.

Originality/value

The main originality of the research is to reveal the effect of GO and SiO2 nanoparticles on fretting behavior of UHMWPE. The result indicated hybrids of GS were promising nanofiller for improving the fretting wear performance of UHMWPE.

Details

Industrial Lubrication and Tribology, vol. 73 no. 2
Type: Research Article
ISSN: 0036-8792

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Article

Mica Grujicic, Jennifer Snipes, S Ramaswami, Vasudeva Avuthu, Chian-Fong Yen and Bryan Cheeseman

Traditionally, an armor-grade composite is based on a two-dimensional (2D) architecture of its fiber reinforcements. However, various experimental investigations have…

Abstract

Purpose

Traditionally, an armor-grade composite is based on a two-dimensional (2D) architecture of its fiber reinforcements. However, various experimental investigations have shown that armor-grade composites based on 2D-reinforcement architectures tend to display inferior through-the-thickness mechanical properties, compromising their ballistic performance. To overcome this problem, armor-grade composites based on three-dimensional (3D) fiber-reinforcement architectures have recently been investigated experimentally. The paper aims to discuss these issues.

Design/methodology/approach

In the present work, continuum-level material models are derived, parameterized and validated for armor-grade composite materials, having four (two 2D and two 3D) prototypical reinforcement architectures based on oriented ultra-high molecular-weight polyethylene fibers. To properly and accurately account for the effect of the reinforcement architecture, the appropriate unit cells (within which the constituent materials and their morphologies are represented explicitly) are constructed and subjected to a series of virtual mechanical tests (VMTs). The results obtained are used within a post-processing analysis to derive and parameterize the corresponding homogenized-material models. One of these models (specifically, the one for 0°/90° cross-collimated fiber architecture) was directly validated by comparing its predictions with the experimental counterparts. The other models are validated by examining their physical soundness and details of their predictions. Lastly, the models are integrated as user-material subroutines, and linked with a commercial finite-element package, in order to carry out a transient non-linear dynamics analysis of ballistic transverse impact of armor-grade composite-material panels with different reinforcement architectures.

Findings

The results obtained clearly revealed the role the reinforcement architecture plays in the overall ballistic limit of the armor panel, as well as in its structural and damage/failure response.

Originality/value

To the authors’ knowledge, the present work is the first reported attempt to assess, computationally, the utility and effectiveness of 3D fiber-reinforcement architectures for ballistic-impact applications.

Details

International Journal of Structural Integrity, vol. 7 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

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Article

Mayyadah S. Abed, Payman S. Ahmed, Jawad K. Oleiwi and Basim M. Fadhil

Composite laminates are considered one of the most popular damage-resistant materials when exposed to impact force in civil and military applications. In this study, a…

Abstract

Purpose

Composite laminates are considered one of the most popular damage-resistant materials when exposed to impact force in civil and military applications. In this study, a comparison of composites 12 and 20 layers of fabrics Kevlar and ultrahigh-molecular-weight poly ethylene (UHMWPE)-reinforced epoxy under low-velocity impacts represented by drop-weight impact and Izod pendulum impact has been done. During the Izod test, Kevlar-based composite showed damage at the composite center and fiber breakages. Whereas delamination was observed for UHMWPE reinforced epoxy (PE). The maximum impact strength was for Kevlar-reinforced epoxy (KE) and increases with the number of laminates. Drop-weight impact test showed the highest absorbed energy for (KE) composites. The results revealed that different behavior during the impact test for composites belongs to the impact mechanism in each test.

Design/methodology/approach

Aramid 1414 Kevlar 49 and UHMWPE woven fabrics were purchased from Yixing Huaheng High-Performance Fiber Textile Co. Ltd, with specifications listed in Table 1. Epoxy resin (Sikafloor-156) is supplied from Sika AG. Sikafloor-156 is a two-part, low-viscosity, solvent-free epoxy resin, with compressive strength ∼95 N/mm², flexural strength ∼30 N/mm² and shore D hardness 83 (seven days). The mixture ratio of A/B was one-third volume ratio. Two types of laminated composites with different layers 12 and 20 were prepared by hand layup: Kevlar–epoxy and UHMWPE–epoxy composites as shown in Figure 1. Mechanical pressure was applied to remove bubbles and excess resin for 24 h. The composites were left in room temperature for seven days, and then composite plates were cut for the desired dimensions. Low-velocity impact testing, drop-weight impact, drop tower impact system INSTRON CEAST 9350 (see Figure 2) was facilitated to investigate impact resistance of composites according to ASTM D7137M (Test Method for Compressive, 2005). Low-velocity impact tests have been performed at room temperature for composite with dimensions 10 × 15 cm2 utilizing a drop tower (steel indenter diameter 19.85 mm as shown in Figure 3), height (800 mm), drop mass (5 kg) and speed (3.96 m/s). Special impact equipment consisting of vertically falling impactor was used in the test. The energy is obtained from Drop tower impact systems, (2009) E = ½ mv2 (2.1). The relationship between force–time, deformation–time and energy–time and deformation was obtained. Energy–deformation and force–deformation relationships were also obtained. The depth of penetration and the radius of impactor traces were recorded. Izod pendulum impact test of plastics was applied according to ASTM D256 (Test Method for Compressive, 2005). Absorbed energy was recorded to compute the impact strength of the specimen. The specimen before the test is shown in Figure 4.

Findings

In order to investigate two types of impact: drop-weight impact and Izod impact on damage resistance of composites, the two tests were done. Drop-weight impact is dropping a known weight and height in a vertical direction with free fall, absorbed energy can be calculated. Izod impact measures the energy required to break a specimen by striking a specific size bar with a pendulum (Test Method for Compressive, 2005; Test Methods for Determining, 2018). The results obtained with the impact test are presented. Figure 5 shows the histogram bars of impact strength of composites. It can be noticed that Kevlar–epoxy (KE) composites give higher energy strength than UHMWPE–epoxy (PE) in 12 and 20 plies. The increasing percentage is about 18.5 and 5.7%. It can be observed in Figure 6 that samples are not destructed completely due to fiber continuity. Also, the delamination occurs obviously for UHMWPE–epoxy more than for Kevlar-based composite, which may due to weak binding between UHMWPE with an epoxy relative with Kevlar.

Practical implications

The force–time curves for Kevlar–epoxy (KE) and UHMWPE–epoxy (PE) composites with 12 and 20 plies are illustrated respectively in Figure 7. The contact duration between indenter and composite surface is repented by the force–time curves, so the maximum force reaches with certain displacement. It can be seen that maximum force was (13,209, 18,734.9, 23,271.07 and 19,825.38 N) at the time (3.97, 4.43, 3.791 and 4.198 ms) for 12 KE, 12 PE, 20 KE and 20 PE, respectively. The sharp peaks of KE composite are due to the lower ductility of Kevlar compared with UHMWPE. These results agree with the results of Ahmed et al. (2016). Kevlar-based composites (KE) showed lower impact force and crack propagates in the matrix with fast fiber breakage compared with PE composites, whereas the latter did not suffer from fabric breakage in 12 and 20 plies any more (see Figure 8). Figure 9 illustrates force–deformation curves, for 12 and 20 plies of Kevlar–epoxy (KE) and UHMWPE–epoxy (PE) composites. Curve's slop is considered the specimen's stiffness and the maximum displacement. To investigate the impact behavior of the four different composites, the comparison was made among the relative force–deformation curves. The maximum displacement was 5.119, 3.443, 1.173 and 1.17 mm for 12KE, 12 PE, 20 KE and 20 PE, respectively. It seems that UHMWPE-based composite (PE) presents lower deformation than Kevlar-based composites (KE) at a same number of laminates, although the maximum displacement is for 12 PE and 12 KE (see Figure 8). Kevlar-based composites (KE) showed more damage than UHMWPE-based composite (PE), so the maximum displacement is always higher for KE specimens with maximum indenter trace diameter (D∼11.27 mm). The onset of cracks begins along fibers on the impacted side for 20 KE and 20 PE specimens with lower indenter trace (D∼5.42 and 5.96 mm), respectively (see Table 2). These results refer to the lower stiffness of KE composites (see the slope of the curve) relative to PE composites. This result agreed with (Vieille et al., 2013) when they found that the theoretical stiffness of laminated composite during drop-weight impact depends significantly on fiber nature (Fadhil, 2013). The matrix cracking is the first type of damage that may not change stiffness of composites overall. Material stiffness changes due to the stress concentration represented by matrix cracks, delamination and fiber breakage (Hancox, 2000). Briefly, the histogram (see Figure 10) showed that the best impact behavior was for 20 KE, highest impact force with lower deformation, indenter trace diameter and contact time. Absorbed energy–time and absorbed energy–deformation curves for composites are shown in Figures 11 and 12, respectively. The maximum absorbed energy was (36.313, 29.952, 9.783 and 6.928 J) for 12 KE, 12 PE, 20 KE and 20 PE, respectively. Test period time is only 8 ms, but the time in which composites reached maximum absorbed energy was (4.413, 3.636, 2.394 and 2.408 ms). The maximum absorbed energy was for 12 KE with lower rebound energy because part of kinetic energy transferred to potential energy kept in the composite as material damage (see Figures 3 and 4). This composite absorbs more energy as material damage which kept as potential energy. Whereas other composites 12 PE, 20 PE and 20 KE showed less damage, lower absorbed energy and higher rebound energy, which appeared in different peak behavior as the negative value of energy. Also from the absorbed energy–time curves, it had been noticed significantly the maximum contact time of indenter with composite was 4.413 ms for 12 KE, which exhibits higher deformation (5.119 mm), whereas other composites 12 PE, 20 KE and 20 PE showed less damage, contact time and deformation as (3.443, 1.173, 1.17 mm), respectively.

Originality/value

The main goal of the current study is to evaluate the performances of armor composite made off of Kevlar and UHMWPE fabrics reinforced epoxy thermosetting resin under the low-velocity impact. Several plates of composites were prepared by hand layup. Izod and drop-weight impact tests were facilitated to get an indication about the absorbed energy and strength of the armors.

Details

Multidiscipline Modeling in Materials and Structures, vol. 16 no. 6
Type: Research Article
ISSN: 1573-6105

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Article

Guomei Chen, Zifeng Ni, Shanhua Qian and Yongwu Zhao

The purposes of this paper are to investigate the biotribological behaviour of Vitamin E-blended highly cross-linked ultra-high molecular weight polyethylene (HXL-UHMWPE…

Abstract

Purpose

The purposes of this paper are to investigate the biotribological behaviour of Vitamin E-blended highly cross-linked ultra-high molecular weight polyethylene (HXL-UHMWPE) under multi-directional motion by using a CUMT II artificial joint hip simulator and compare it with HXL-UHMWPE and conventional UHMWPE.

Design/methodology/approach

The biotribological behaviour of conventional, highly cross-linked and Vitamin E-blended highly cross-linked UHMWPE acetabular cups counterfaced with CoCrMo alloy femoral head under multi-directional motion were investigated by using CUMT-II artificial hip joint simulator for one-million walking cycles. The test environment was at 36.5 ± 0.5°C and 25 per cent bovine serum was used as lubricant. A Paul cycle load with a peak of 784 N was applied; the motion and loading were synchronized at 1 Hz.

Findings

The wear resistance of Vitamin E-blended highly cross-linked UHMWPE was significantly higher than that of highly cross-linked and conventional UHMWPE. The wear marks observed from the worn surface of UHMWPE were multi-directional, with no dominant wear direction. Only abrasion occurred on the surface of Vitamin E-blended highly cross-linked UHMWPE, while yielding and accumulated plastic flow processes occurred on the surface of conventional UHMWPE and flaking-like facture and abrasion occurred on the surface of highly cross-linked UHMWPE.

Originality/value

Besides the prevention of oxidative degradation, blending with Vitamin E can also reduce the incidence of fatigue crack occurred in the surface layer of HXL-UHMWPE samples. Therefore, the wear resistance of HXL-UHMWPE under multi-directional motion can be further enhanced by blending with Vitamin E.

Details

Industrial Lubrication and Tribology, vol. 68 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

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Article

Changhui Song, Aibing Huang, Yongqiang Yang, Zefeng Xiao and Jia-kuo Yu

This study aims to achieve customized prosthesis for total joint arthroplasty and total hip arthroplasty. Selective laser sintering (SLS) as additive manufacturing could…

Abstract

Purpose

This study aims to achieve customized prosthesis for total joint arthroplasty and total hip arthroplasty. Selective laser sintering (SLS) as additive manufacturing could enable small-scale fabrication of customized Ultra High Molecular Weight Polyethylene (UHMWPE) components; however, the processes for SLS of UHMWPE need to be improved.

Design/methodology/approach

This paper begins by improving the preheating system of the SLS fabricating equipment and then fabricating cuboids with the same size and cuboids with same volume and different size to study the warpage, demonstrating the effect of the value and uniformity of the preheating temperature on component fabrication. Warpage, density and tensile properties are investigated from the perspective of energy input density. Finally, complicated industrial parts are produced effectively by using optimized technological parameters.

Findings

The results show that components can be fabricated effectively after the optimization of the SLS technological parameters i.e. the preheating temperature the laser power the scanning interval and the scanning speed. The resulting warpage was found to be less than 0.1 mm along with the density as 83.25 and the tensile strength up to 14.1 Mpa. UHMWPE sample parts with good appearance and strength are obtained after ascertaining the effect of each factor on the fabrication of the sample parts.

Originality/value

It is very challenging to fabricate UHMWPE sample parts by SLS. This is a new step in the fabrication of customized UHMWPE sample parts.

Details

Rapid Prototyping Journal, vol. 23 no. 6
Type: Research Article
ISSN: 1355-2546

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Article

Binnur Sagbas

The aim of this study is to determine the effect of argon plasma surface modification on tribological properties of conventional ultra-high molecular weight polyethylene

Abstract

Purpose

The aim of this study is to determine the effect of argon plasma surface modification on tribological properties of conventional ultra-high molecular weight polyethylene (UHMWPE) and vitamin E-blended UHMWPE. In previous studies, some researchers conducted a study on argon plasma surface modification of UHMWPE, but there is no study about argon plasma surface modification of VE-UHMWPE. So another objective of this paper is to compare the results for both the material groups.

Design/methodology/approach

UHMWPE and vitamin E-blended UHMWPE sample surfaces were modified by microwave-induced argon plasma to increase tribological properties of the materials. The modified surfaces were evaluated in terms of wettability and wear behavior. Wettability of the surfaces was determined by contact angle measurements. Wear behavior was examined by ball-on-disc wear tests under lubrication with 25 per cent bovine serum.

Findings

Argon plasma surface modification enhanced the wear resistance and surface wettability properties of conventional UHMWPE and VE-UHMWPE. Wear factor of argon plasma-treated samples reduced, but for VE-UHMWPE samples, this reduction was not as high as the conventional UHMWPE’s wear factor.

Originality/value

In previous studies, some researchers have studied on argon plasma surface modification of UHMWPE, but there is no study about argon plasma surface modification of VE-UHMWPE.

Details

Industrial Lubrication and Tribology, vol. 68 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

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