scholarly journals Viscoelastic Finite Line Contact of Thin Bonded Layered Solids of Low Elastic Modulus

2020 ◽  
Vol 10 (10) ◽  
pp. 3363
Author(s):  
Vasilis Votsios ◽  
Patricia Johns-Rahnejat ◽  
Homer Rahnejat

A new finite element-based contact mechanics analysis of layered viscoelastic solids of low elastic modulus is presented. The methodology is based on the Maxwell viscoelastic element, with stress relaxation taken into account by the Prony series’ representation of the bulk and shear material moduli. Simultaneous solutions for deviatoric and volumetric stresses were obtained under instantaneous elastic and subsequent viscoelastic relaxation, at multiples of the relaxation time of a Highly Filled Carbon Polymer (HFCP) layer. The results of the analysis were validated by a constructed, multi-layered sandwich sensor comprising the HFCP sensing elements covered by a protective silicone rubber surface of very low elastic modulus. The combined numerical-experimental approach, and the validated viscoelastic layered contact mechanics represent the original contribution of this paper, not hitherto reported in literature.

Author(s):  
Pinghua Ou ◽  
Cong Hao ◽  
Jue Liu ◽  
Rengui He ◽  
Baoqi Wang ◽  
...  

AbstractTi–xZr (x = 5, 15, 25, 35, 45% wt%) alloys with low elastic modulus and high mechanical strength were fabricated as a novel implant material. The biocompatibility of the Ti–xZr alloys was evaluated by osteoblast-like cell line (MG63) in terms of cytotoxicity, proliferation, adhesion, and osteogenic induction using CCK-8 and live/dead cell assays, electron microscopy, and real-time PCR. The Ti–xZr alloys were non-toxic and showed superior biomechanics compared to commercially pure titanium (cpTi). Ti–45Zr had the optimum strength/elastic modulus ratio and osteogenic activity, thus is a promising to used as dental implants.


2021 ◽  
Vol 81 ◽  
pp. 13-25
Author(s):  
Diangeng Cai ◽  
Xiaotong Zhao ◽  
Lei Yang ◽  
Renxian Wang ◽  
Gaowu Qin ◽  
...  

2004 ◽  
Vol 70 (17) ◽  
Author(s):  
Hideaki Ikehata ◽  
Naoyuki Nagasako ◽  
Tadahiko Furuta ◽  
Atsuo Fukumoto ◽  
Kazutoshi Miwa ◽  
...  

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 712 ◽  
Author(s):  
Peiyou Li ◽  
Xindi Ma ◽  
Duo Wang ◽  
Hui Zhang

The microstructural and mechanical properties of β-type Ti85-xNb10+xSn5 (x = 0, 3, 6, 10 at.%) alloys with low elastic modulus were investigated. The experimental results show that the Ti85Nb10Sn5 and Ti75Nb20Sn5 alloys are composed of simple α and β phases, respectively; the Ti82Nb13Sn5 and Ti79Nb16Sn5 alloys are composed of β and α″ phases. The content of martensite phase decreases with the increase of Nb content. The Ti82Nb13Sn5 and Ti79Nb16Sn5 alloys show an inverse martensitic phase transition during heating. The Ti85Nb10Sn5 and Ti82Nb13Sn5 alloys with the small residual strain exhibit the good superelastic properties in 10-time cyclic loading. The reduced elastic modulus (Er) of the Ti75Nb20Sn5 alloy (61 GPa) measured by using the nanoindentation technique is 2–6 times of that of human bone (10–30 GPa), and is smaller than that of commercial Ti-6Al-4V biomedical alloy (120 GPa). The Ti75Nb20Sn5 alloy can be considered as a novel biomedical alloy. The wear resistance (H/Er) and anti-wear capability (H3/Er2) values of the four alloys are higher than those of the CP–Ti alloy (0.0238), which indicates that the present alloys have good wear resistance and anti-wear capability.


2020 ◽  
Vol 72 (5) ◽  
pp. 695-701
Author(s):  
Mingyu Zhang ◽  
Jing Wang ◽  
Peiran Yang ◽  
Zhaohua Shang ◽  
Yi Liu ◽  
...  

Purpose This paper aims to study the influence of the dimension change of bush-pin on the pressure, oil film thickness, temperature rise and traction coefficient in contact zone by using a thermal elastohydrodynamic lubrication (EHL) model for finite line contact. Concretely, the effects of the equivalent curvature radius of the bush and the pin, and the length of the bush are investigated. Design/methodology/approach In this paper, the contact between the bush and pin is simplified as finite line contact. The lubrication state is studied by numerical simulation using steady-state line contact thermal EHL. A constitutive equation Ree–Eyring fluid is used in the calculations. Findings It is found that by selecting an optimal equivalent radius of curvature and prolonging the bush length can improve the lubrication state effectively. Originality/value Under specific working conditions, there exists an optimal equivalent radius to maximize the minimum oil film thickness in the contact zone. The increase of generatrix length will weaken the stress concentration effect in the rounded corner area at both ends of the bush, which can improve the wear resistance of chain. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0448.


2007 ◽  
Vol 124-126 ◽  
pp. 1669-1672 ◽  
Author(s):  
Hi Won Jeong ◽  
Seung Eon Kim ◽  
Chang Yong Jo ◽  
Yong Tae Lee ◽  
Joong Kuen Park

The titanium alloys containing the Nb transition elements have been investigated as the Ni-free shape memory and the biomedical alloys with a low elastic modulus. The mechanical properties of the alloys depended upon the meta-stable phases like the α`, α``, ω. To study the martensitic transformations from the β to α`` or α` the Ti-xNb (x=0 to 40 wt%) alloys were melted into the button type ingots using a VAR, and followed by the water-quenching after the soaking at 1000oC for 2hrs. The crystallography of the martensitic phases in the water-quenched alloys was analyzed using a XRD. The diffraction peaks of the orthorhombic martensites were identified by the crystallographic relationship with the bcc matrix. The lattice parameters of the orthorhombic martensites were varied continuously with the contents of the Nb elements. The martensitic transformations of the alloys were studied using the phenomenological theory of Bowles and Mackenzie.


2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Zhenghai Wu ◽  
Yingqiang Xu ◽  
Kaian Liu

Abstract The angular misalignment of the tapered roller contact pair aggravates the stress edge effect and the stress concentration effect at the contact field, which in turn would affect bearing capacity and fatigue life of the contact pair. In this paper, based on the angular misalignment, the geometric interference model of the tapered roller contact pair was established. And two types of logarithmic crowning models for the roller profile design were theoretically deduced, in which design redundancy was considered through the quadratic processing of the pre-pressure. Then, with the discrete convolution and fast Fourier transform (DC-FFT) method and the conjugate gradient method (CGM), contact characteristics of the tapered roller with these two logarithmic profiles were verified. The results show that two profiles can effectively prevent the stress edge/concentration effect, improve contact pressure distribution and stress field of the roller in misalignment state, and ensure that the contact condition in alignment state is not greatly affected. The logarithmic crowning scheme is also suitable for the profile design of heavy-duty tapered rollers and can provide a reference for the crowning of other finite-line contact pairs under angular misalignment.


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