Read by QxMD icon Read

tensile stress

Sijia Zhang, Vahhab Zarei, Beth A Winkelstein, Victor H Barocas
The facet capsular ligaments encapsulate the bilateral spinal facet joints and are common sources of painful injury due to afferent innervation. These ligaments exhibit architectural complexity, which is suspected to contribute to the experimentally observed lack of co-localization between macroscopic strain and microstructural tissue damage. The heterogeneous and multiscale nature of this ligament, combined with challenges in experimentally measuring its microscale mechanics, hinders the ability to understand sensory mechanisms under normal or injurious loading...
August 18, 2017: Biomechanics and Modeling in Mechanobiology
Pang Zhu, Yonghong Deng, Chaoyang Wang
Dual crosslinked system has been proved to be an efficient method to obtain tough and high strength hydrogels. Herein, we synthesized a novel graphene oxide/p(acrylamide-co-poly(ethylene glycol) methyl ether methacrylate)/α-cyclodextrin (GO/P(AM-co-PEGMA)/CD) physical dual crosslinked hydrogel via copolymerization of AM and PEGMA in the α-CD/GO solution. The polymer main chains adsorb onto the GO surface resulting in the first crosslinked system and multiple hydrogen bonds between α-CDs that thread on the PEGMA side chains establish the second crosslinked system...
October 15, 2017: Carbohydrate Polymers
Feilong Guo, Huihui Yu, Chenyu Wu, Yunchang Xin, Cong He, Qing Liu
A study regarding the effect of texture on tensile yield strength and hardness of an extruded Mg-15Gd-0.5Zr rod was performed, with a great emphasis laid on the relevant mechanisms. A 7% pre-tension along the extrusion direction (ED) in the solid solution condition was used to transform the texture from a broad distribution of basal poles with a peak approximately 45° with respect to the ED into a texture with basal poles largely perpendicular to the ED. This texture variation enhances the yield strength of peak aged sample by approximately 103 MPa, while hardly increases the peak hardness...
August 17, 2017: Scientific Reports
Moonsang Lee, Dmitry Mikulik, Mino Yang, Sungsoo Park
We investigate the stress evolution of 400 µm-thick freestanding GaN crystals grown from Si substrates by hydride vapour phase epitaxy (HVPE) and the in situ removal of Si substrates. The stress generated in growing GaN can be tuned by varying the thickness of the MOCVD AlGaN/AlN buffer layers. Micro Raman analysis shows the presence of slight tensile stress in the freestanding GaN crystals and no stress accumulation in HVPE GaN layers during the growth. Additionally, it is demonstrated that the residual tensile stress in HVPE GaN is caused only by elastic stress arising from the crystal quality difference between Ga- and N-face GaN...
August 17, 2017: Scientific Reports
Li-Fang Wang, Xiaolin Shu, Guang-Hong Lu, Fei Gao
An embedded-atom method potential has been developed for modeling hydrogen in body-centered-cubic (bcc) tungsten by fitting to an extensive database of density functional theory (DFT) calculations. Comprehensive evaluations of the new potential are conducted by comparing various hydrogen properties with DFT calculations and available experimental data, as well as all the other tungsten-hydrogen potentials. The new potential accurately reproduces the point defect properties of hydrogen, the interaction among hydrogen atoms, the interplay between hydrogen and a monovacancy, and the thermal diffusion of hydrogen in tungsten...
August 17, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Thomas Jenkins, Sean Meehan, Behnam Pourdeyhimi, Dianne Little
Various biomaterial technologies are promising for tissue engineering, including electrospinning, but commercial scale-up of throughput is difficult. The goal of the study was to evaluate meltblown fabrics as candidate scaffolds for rotator cuff tendon tissue engineering. Meltblown poly(lactic acid) fabrics were produced with several polymer crystallinities and airflow velocities (500(low), 900(medium) or 1400(high) m<sup>3</sup>air/hour/m fabric). Fiber diameter, alignment, and baseline bi-directional tensile mechanical properties were evaluated...
August 17, 2017: Tissue Engineering. Part A
Xiaohui Gong, Xiaojuan Xu, Sisi Lin, Yu Cheng, Jianhua Tong, Yongyu Li
The aim of the current study was to investigate the effects of early-stage dextran sodium sulfate (DSS)-induced mouse colitis on the biomechanical properties and microstructure of colon walls. In the present study, colitis was induced in 8-week-old mice by the oral administration of DSS, and then 10 control and 10 experimental colitis samples were harvested. Uniaxial tensile tests were performed to measure the ultimate tensile strength and ultimate stretches of colon tissues. In addition, histological investigations were performed to characterize changes in the microstructure of the colon wall following treatment...
August 2017: Experimental and Therapeutic Medicine
Ming Chen, Juan Xia, Jiadong Zhou, Qingsheng Zeng, Kaiwei Li, Kazunori Fujisawa, Wei Fu, Ting Zhang, Jing Zhang, Zhe Wang, Zhixun Wang, Xiaoting Jia, Mauricio Terrones, Ze Xiang Shen, Zheng Liu, Lei Wei
Thermoplastic polymers subjected to a continuous tensile stress experience a state of mechanical instabilities, resulting in neck formation and propagation. The necking process with strong localized strain enables the transformation of initially brittle polymeric materials into robust, flexible, and oriented forms. Here we harness the polymer-based mechanical instabilities to control the fragmentation of atomically thin transition metal dichalcogenides (TMDs). We develop a simple and versatile nanofabrication tool to precisely fragment atom-thin TMDs sandwiched between thermoplastic polymers into ordered and atomically perfect TMD nanoribbons in arbitrary directions regardless of the crystal structures, defect content, and original geometries...
August 17, 2017: ACS Nano
Yishuo Guo, Jun Liu, Youping Wu, Liqun Zhang, Zhao Wang, Ying Li
Through united-atom molecular dynamics simulations, we build a series of graphene (GP) reinforced cis-1,4-polybutadiene (cis-PB) models with two novel GP structures, intercalated and stacked GP structures, to investigate the effect of different GP packing patterns on the chain structure, chain dynamics, uniaxial tension and visco-elastic behaviors, and correlate the microscopic mechanism with macroscopic mechanical properties. Simulation results show that the interlayer polymer chains in the void of intercalated GPs are strongly confined, leading to higher bond orientation of polymer chains during the stretch process compared with monodisperse systems...
August 15, 2017: Physical Chemistry Chemical Physics: PCCP
Melika Mohammadkhah, Paula Murphy, Ciaran K Simms
The tension/compression asymmetry observed in the stress-stretch response of skeletal muscle is not well understood. The collagen network in the extracellular matrix (ECM) almost certainly plays a major role, but the details are unknown. This paper reports qualitatively and quantitatively on skeletal muscle ECM reorganization during applied deformation using confocal imaging of collagen through use of a fluorescently-tagged specific collagen binding protein (CNA35-EGFP) of porcine and chicken muscle samples under tensile and compressive deformation in both the fibre and cross-fibre directions...
August 5, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Sheetal R Inamdar, David P Knight, Nicholas J Terrill, Angelo Karunaratne, Fernando Cacho-Nerin, Martin M Knight, Himadri S Gupta
Articular cartilage is a natural biomaterial whose structure at the micro- and nanoscale is critical for healthy joint function and where degeneration is associated with widespread disorders such as osteoarthritis. At the nanoscale, cartilage mechanical functionality is dependent on the collagen fibrils and hydrated proteoglycans that form the extracellular matrix. The dynamic response of these ultrastructural building blocks at the nanoscale, however, remains unclear. Here we measure time-resolved changes in collagen fibril strain, using small angle X-ray diffraction during compression of bovine and human cartilage explants...
August 11, 2017: ACS Nano
Junkai Deng, Yuefeng Yin, Huanhuan Niu, Xiangdong Ding, Jun Sun, Nikhil V Medhekar
The edge states are of particular importance to understand fundamental properties of finite two-dimensional (2D) crystals. Based on first-principles calculations, we investigated on the bare zigzag boron nitride nanoribbons (zzBNNRs) with different spin-polarized states well localized at and extended along their edges. Our calculations examined the edge stress, which is sensitively dependent on the magnetic edge states, for either B-terminated edge or N-terminated edge. Moreover, we revealed that different magnetic configurations lead to a rich spectrum of electronic behaviors at edges...
August 10, 2017: Scientific Reports
David Taylor
Many biological materials fail by cracking. Examples are bone fractures, contact damage in eggs, splits in bamboo culm and defects in cartilage. The mechanical property that best describes failure by cracking is fracture toughness, which quantifies the ease with which cracks propagate and defines a material's tolerance for pre-existing cracks and other stress concentrating features. The measurement of fracture toughness presents some challenges, especially for biological materials. To obtain valid results requires care and, in many cases, considerable ingenuity to design an appropriate specimen and test protocol...
July 5, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Hui Peng, Jianxiong Lu, Jiali Jiang, Jinzhen Cao
To provide comprehensive data on creep behaviors at relative humidity (RH) isohume conditions and find the basic characteristics of mechano-sorptive (MS) creep (MSC), the tensile creep behaviors, "viscoelastic creep (VEC)" at equilibrium moisture content and MSC during adsorption process, were performed on Chinese fir in the longitudinal direction under 20%, 40%, 60% and 80% RH (25 °C) and at 1, 1.3, and 1.6 MPa, respectively. The free swelling behavior was also measured, where the climate conditions corresponded with MSC tests...
August 10, 2017: Materials
Shan Xia, Shixin Song, Xiuyan Ren, Guanghui Gao
The introduction of SiO2 particles as crosslinking points into hydrogels has been recognized as a suitable way for toughening hydrogels, due to their versatile functionalization and large specific surface area. However, chemically linked SiO2 nanocomposite hydrogels often exhibited negligible fatigue resistance and poor self-recoverable properties due to the irreversible cleavage of covalent bonds. Here, we proposed a novel strategy to improve stretchability, fatigue resistance and self-recoverable properties of hydrogels by using SiO2-g-poly(butyl acrylate) core-shell inorganic-organic hybrid latex particles as hydrophobic crosslinking centers for hydrophobic association...
August 4, 2017: Soft Matter
Chenhui Wei, Wancheng Zhu, Shikuo Chen, Pathegama Gamage Ranjith
This paper proposes a coupled thermal-hydrological-mechanical damage (THMD) model for the failure process of rock, in which coupling effects such as thermally induced rock deformation, water flow-induced thermal convection, and rock deformation-induced water flow are considered. The damage is considered to be the key factor that controls the THM coupling process and the heterogeneity of rock is characterized by the Weibull distribution. Next, numerical simulations on excavation-induced damage zones in Äspö pillar stability experiments (APSE) are carried out and the impact of in situ stress conditions on damage zone distribution is analysed...
October 31, 2016: Materials
Chun Su, Jianzhong Zhou, Xiankai Meng, Shu Huang
As a new treatment process after welding, the process parameters of laser shock peening (LSP) in dynamic strain aging (DSA) temperature regimes can be precisely controlled, and the process is a non-contact one. The effects of LSP at elevated temperatures on the distribution of the surface residual stress of AA6061-T6 welded joints were investigated by using X-ray diffraction technology with the sin²ϕ method and Abaqus software. The fatigue life of the welded joints was estimated by performing tensile fatigue tests...
September 26, 2016: Materials
Yu Wang, Qingsong Wang, Haodong Chen, Jinhua Sun, Linghui He
This paper explores the fracture process based on finite element simulation. Both probabilistic and deterministic methods are employed to model crack initiation, and several commonly used criteria are utilized to predict crack growth. It is concluded that the criteria of maximum tensile stress, maximum normal stress, and maximum Mises stress, as well as the Coulomb-Mohr criterion are able to predict the initiation of the first crack. The mixed-mode criteria based on the stress intensity factor (SIF), energy release rate, and the maximum principal stress, as well as the SIF-based maximum circumferential stress criterion are suitable to predict the crack propagation...
September 22, 2016: Materials
Jiong-Shiun Hsu, Chang-Chun Lee, Bor-Jiunn Wen, Pei-Chen Huang, Chi-Kai Xie
Stress-induced failure is a critical concern that influences the mechanical reliability of an indium tin oxide (ITO) film deposited on a transparently flexible polyethylene terephthalate (PET) substrate. In this study, a cycling bending mechanism was proposed and used to experimentally investigate the influences of compressive and tensile stresses on the mechanical stability of an ITO film deposited on PET substrates. The sheet resistance of the ITO film, optical transmittance of the ITO-coated PET substrates, and failure scheme within the ITO film were measured to evaluate the mechanical stability of the concerned thin films...
August 24, 2016: Materials
Zhaobin Zhang, Xiao Li
The shearing of natural fractures is important in the permeability enhancement of shale gas reservoirs during hydraulic fracturing treatment. In this work, the shearing mechanisms of natural fractures are analyzed using a newly proposed numerical model based on the displacement discontinuities method. The fluid-rock coupling system of the model is carefully designed to calculate the shearing of fractures. Both a single fracture and a complex fracture network are used to investigate the shear mechanisms. The investigation based on a single fracture shows that the non-ignorable shearing length of a natural fracture could be formed before the natural fracture is filled by pressurized fluid...
August 23, 2016: Materials
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"