Read by QxMD icon Read

tensile stress

Yeon-Ho Lee, Hyun-Oh Kim, Youn-Jea Kim
Stretchable heaters are mechanically and biomedically advantageous because they are more flexible than the conventional microheaters. To determine the way that a heater can be used appropriately in a wide range of application fields, studies on the mechanical and thermal characteristics regarding various film configurations are underway. In this study, the mechanical characteristics of conical-frustum-patterned stretchable heaters with various configurations with upper-radius (R1), bottom-radius (R2), and height (h) aspect ratios were numerically investigated when tensile forces and bending moments were applied to the film of heater...
September 1, 2018: Journal of Nanoscience and Nanotechnology
Chuan Liu, Chunjing Wang, Xiaohua Cheng, Yi Yan, Jiawei Yang, Yuhang Guo
The stress distributions in a thick welded specimen with a partial repair weld were measured with the three-cut contour method. The longitudinal stress maps in the original weld and the repair weld were obtained and the transverse stress map at the weld centerline in the original weld was acquired. The difference between the longitudinal stress in the partial repair weld and that in the original weld was investigated. Results show that the longitudinal stress increases significantly within the entire repair region with a peak tensile longitudinal stress close to the yield strength of weld material; and the longitudinal stress in the region above the repair weld decreases distinctly after repair; the introduction of the partial repair weld does not affect the stress distribution trend in the original weld (whether it is beyond or above the repair weld), and it has a slight effect on the tensile stress distribution width in the repair region...
April 20, 2018: Materials
Kaiyun Jin, Silan Zhang, Susheng Zhou, Jian Qiao, Yanhui Song, Jiangtao Di, Dengsong Zhang, Qingwen Li
Artificial yarn/fiber muscles have recently attracted considerable interest for various applications. These muscles can provide large-stroke tensile and torsional actuations, resulting from inserted twists. However, tensional tethering of twisted muscles is generally needed to avoid muscle snarling and untwisting. In this paper a carbon nanotube (CNT) yarn muscle that is tethering-free and twist-stable is reported. The yarn muscle is prepared by allowing the self-plying of a coiled CNT yarn. When driven by acetone adsorption, this muscle shows decoupled actuations, which provide fast and reversible ∼13...
April 20, 2018: Nanoscale
Chenxiao Xiong, Lidong Zhang, Meiran Xie, Ruyi Sun
Supramolecular hydrogels that are assembled through dynamic host-guest interactions have presented apparent potential in the construction of materials with promising performance. Herein, a photoregulated hydrogel cross-linked by host-guest interactions with multifunctions of high stretchability, strong toughness, and rapid self-healing property is reported. The hydrogel exhibits unique light-responsive property due to the introduction of two photoisomerized groups. For example, the stress-strain curve of the original hydrogel indicates 1020% rupture strain with the maximum tensile strain value of 214 kPa...
April 20, 2018: Macromolecular Rapid Communications
Amit Banerjee, Daniel Bernoulli, Hongti Zhang, Muk-Fung Yuen, Jiabin Liu, Jichen Dong, Feng Ding, Jian Lu, Ming Dao, Wenjun Zhang, Yang Lu, Subra Suresh
Diamonds have substantial hardness and durability, but attempting to deform diamonds usually results in brittle fracture. We demonstrate ultralarge, fully reversible elastic deformation of nanoscale (~300 nanometers) single-crystalline and polycrystalline diamond needles. For single-crystalline diamond, the maximum tensile strains (up to 9%) approached the theoretical elastic limit, and the corresponding maximum tensile stress reached ~89 to 98 gigapascals. After combining systematic computational simulations and characterization of pre- and postdeformation structural features, we ascribe the concurrent high strength and large elastic strain to the paucity of defects in the small-volume diamond nanoneedles and to the relatively smooth surfaces compared with those of microscale and larger specimens...
April 20, 2018: Science
Benan Shu, Shaopeng Wu, Lijie Dong, Qing Wang, Quantao Liu
This work aims to develop an original alginate micro-emulsion combining with droplets microfluidic method to produce multinuclear Ca-alginate microcapsules containing rejuvenator for the self-healing of bituminous binder. The sizes of the Ca-alginate microcapsules could be easily controlled by tuning flow rates of the continuous and dispersed phases. The addition of a surfactant Tween80 not only improved the stability of the emulsion, but it also effectively reduced the size of the microcapsules. Size predictive mathematical model of the microcapsules was proposed through the analysis of fluid force...
April 19, 2018: Materials
Wenguang Zhang, Jiaqi Tang, Zhengwei Li, Yakun Ma
In order to solve the problem of the short lifespan of the neural electrode caused by micro motion, this study designed a novel neural electrode based on lumped compliance compliant mechanism to control different modes of micro-motion in a more effective way. According to the mathematical modeling of the novel neural electrode, the equivalent bending stiffness and equivalent tensile (compression) stiffness were calculated. The results of the finite element analysis based on the mathematical modeling revealed that the novel neural electrode showed excellent micro-motion-attenuation capability...
April 18, 2018: Medical & Biological Engineering & Computing
Fei Xiao, Hong Chen, Xuejun Jin, Zhihua Nie, Tomoyuki Kakeshita, Takashi Fukuda
Ti-51Ni (at%) alloys including coherent precipitates of Ti3 Ni4 exhibits thermally-induced B2-R transformation. If the Ti3 Ni4 is formed under tensile stress, it orientates preferentially so that its habit plane becomes perpendicular to the tensile axis. In such specimens, stress-induced reverse R-B2 transformation is reported to occur. In the present study, the stress-induced reverse R-B2 transformation behavior was studied by infrared camera and in situ X-ray analysis. The infrared camera observation revealed that the temperature of the specimen decreases homogeneously by the application of tensile stress within the resolution of the camera...
April 17, 2018: Scientific Reports
Nicolas R Chevalier, Tinke-Marie de Witte, Annemiek J M Cornelissen, Sylvie Dufour, Véronique Proux-Gillardeaux, Atef Asnacios
During embryonic development, most organs are in a state of mechanical compression because they grow in a confined and limited amount of space within the embryo's body; the early gut is an exception because it physiologically herniates out of the coelom. We demonstrate here that physiological hernia is caused by a tensile force transmitted by the vitelline duct on the early gut loop at its attachment point at the umbilicus. We quantify this tensile force and show that applying tension for 48 h induces stress-dependent elongational growth of the embryonic gut in culture, with an average 90% length increase (max: 200%), 65% volume increase (max: 160%), 50% dry mass increase (max: 100%), and 165% cell number increase (max: 300%); this mechanical cue is required for organ growth as guts not subject to tension do not grow...
April 16, 2018: Scientific Reports
Šarūnas Meskinis, Rimantas Gudaitis, Kestutis Šlapikas, Andrius Vasiliauskas, Arvydas Čiegis, Tomas Tamulevičius, Mindaugas Andrulevičius, Sigitas Tamulevicius
Piezoresistive properties of hydrogenated diamond like carbon (DLC) and diamond like carbon based nickel nanocomposite (DLC:Ni) films were studied in the range of low concentration of nickel nanoparticles. The films were deposited by reactive high power pulsed magnetron sputtering of Ni target and some samples were deposited by direct current reactive magnetron sputtering for comparison purposes. Raman scattering spectroscopy, energy-dispersive X-ray spectrometry and X-ray photoelectron spectroscopy were used to study structure and chemical composition of the films...
April 16, 2018: ACS Applied Materials & Interfaces
Tyler R Long, Robert M Elder, Erich D Bain, Kevin A Masser, Timothy W Sirk, Jian H Yu, Daniel B Knorr, Joseph L Lenhart
The apparent molecular weight between crosslinks (Mc,a) in a polymer network plays a fundamental role in the network mechanical response. We systematically varied Mc,a independent of strong noncovalent bonding by using ring-opening metathesis polymerization (ROMP) to co-polymerize dicyclopentadiene (DCPD) with a chain extender that increases Mc,a or a di-functional crosslinker that decreases Mc,a. We compared the ROMP series quasi-static modulus (E), tensile yield stress (σy), and fracture toughness (KIC and GIC) in the glassy regime with literature data for more polar thermosets...
April 16, 2018: Soft Matter
Z Wang, D Vashishth, R C Picu
Bone toughness emerges from the interaction of several multiscale toughening mechanisms. Recently, the formation of nanoscale dilatational bands and hence the accumulation of submicron diffuse damage were suggested as an important energy dissipation processes in bone. However, a detailed mechanistic understanding of the effect of this submicron toughening mechanism across multiple scales is lacking. Here, we propose a new three-dimensional ultrastructure volume element model showing the formation of nanoscale dilatational bands based on stress-induced non-collagenous protein denaturation and quantify the total energy released through this mechanism in the vicinity of a propagating crack...
April 16, 2018: Biomechanics and Modeling in Mechanobiology
Louis G Malito, Sofia Arevalo, Adam Kozak, Stephen Spiegelberg, Anuj Bellare, Lisa Pruitt
This is the first study to simultaneously measure material properties in tension, compression, nanoindentation as well as microstructure (crystallinity and lamellar level properties) across a wide variety of clinically relevant ultra-high molecular weight polyethylene (UHMWPE) formulations. Methodologies for the measurement of UHMWPE mechanical properties-namely elastic modulus, yield stress, yield strain, ultimate strength, energetic toughness, Poisson's ratio, hardness and constitutive variables-are evaluated...
April 3, 2018: Journal of the Mechanical Behavior of Biomedical Materials
Alexander J Bourque, Gregory C Rutledge
A new empirical potential for layered graphitic materials is reported. Interatomic interactions within a single graphene sheet are modeled using a Stillinger-Weber potential. Interatomic interactions between atoms in different sheets of graphene in the nanoplatelet are modeled using a Lennard-Jones interaction potential. The potential is validated by comparing molecular dynamics simulations of tensile deformation with the reported elastic constants for graphite. The graphite is found to fracture into graphene nanoplatelets when subjected to ∼15% tensile strain normal to the basal surface of the graphene stack, with an ultimate stress of 2...
April 14, 2018: Journal of Chemical Physics
Yongkang Bai, Jiwen Zhang, Xin Chen
A multiresponsive shape memory composite was prepared by incorporating polyaniline (PAn) fibers into polyvinyl alcohol (PVA), where in situ polymerization assisted by surfactant was used to homogeneously disperse PAn fibers in a PVA matrix. The PAn fibers not only increased physical cross-linking points in the system but also served as photothermal conversion reagents, resulting in excellent water-, thermal-, and near-infrared (NIR) light-induced shape memory properties of the composites, where their light-induced shape recovery ratio and speed could be enhanced via the increase of PAn loading percentage and light power density...
April 16, 2018: ACS Applied Materials & Interfaces
Clémence Gingreau, Thomas Lanternier, Laurent Lamaignère, Thierry Donval, Roger Courchinoux, Christophe Leymarie, Jérôme Néauport
At the interface between vacuum and air, optical windows must keep their optical properties, despite being subjected to mechanical stress. In this Letter, we investigate the impact of such stress on the laser-induced damage of fused silica windows at the wavelength of 351 nm in the nanosecond regime. Different stress values, from 1 to 30 MPa, both tensile and compressive, were applied. No effect of the stress on the laser-induced damage was evidenced.
April 15, 2018: Optics Letters
A Chalon, J Favre, B Piotrowski, V Landmann, D Grandmougin, J-P Maureira, P Laheurte, N Tran
STUDY: Implantation of a Left Ventricular Assist Device (LVAD) may produce both excessive local tissue stress and resulting strain-induced tissue rupture that are potential iatrogenic factors influencing the success of the surgical attachment of the LVAD into the myocardium. By using a computational simulation compared to mechanical tests, we sought to investigate the characteristics of stress-induced suture material on porcine myocardium. METHODS: Tensile strength experiments (n = 8) were performed on bulk left myocardium to establish a hyperelastic reduced polynomial constitutive law...
March 28, 2018: Journal of the Mechanical Behavior of Biomedical Materials
B Fereidooni, M R Morovvati, S A Sadough-Vanini
Corrosive solutions have an enormous effect on fatigue life of components in refinery industry. Several post-processing solutions are proposed to improve the weld zone, which is affected by the corrosive solutions. Ultrasonic peening (UP) is developed to enhance the fatigue life, specifically in corrosive environments and corrosion resistance of the components. The enhancement mechanism of UP is based on severe plastic deformation and reduction of tensile residual stress in weld toe. In this research, the fatigue-corrosion life of welded 316 Stainless Steel (SS) pipe is enhanced through utilizing UP process with different diameters of strikers...
March 21, 2018: Ultrasonics
Oscar Araque, Nelson Arzola, Edgar Hernández
This research deals with the fatigue behavior of butt-welded joints, by considering the geometry and post-welding cooling cycles, as a result of cooling in quiet air and immersed in water. ASTM A-36 HR structural steel was used as the base metal for the shielded metal arc welding (SMAW) process with welding electrode E6013. The welding reinforcement was 1 mm and 3 mm, respectively; axial fatigue tests were carried out to determine the life and behavior in cracks propagation of the tested welded joints, mechanical characterization tests of properties in welded joints such as microhardness, Charpy impact test and metallographic analysis were carried out...
April 12, 2018: Materials
Aleksander Kowalski, Wojciech Ozgowicz, Wojciech Jurczak, Adam Grajcar, Sonia Boczkal, Janusz Żelechowski
The paper presents results of the investigations on the effect of low-temperature thermomechanical treatment (LTTT) on the microstructure of AlZn6Mg0.8Zr alloy (7000 series) and its mechanical properties as well as electrochemical and stress corrosion resistance. For comparison of the LTTT effect, the alloy was subjected to conventional precipitation hardening. Comparative studies were conducted in the fields of metallographic examinations and static tensile tests. It was found that mechanical properties after the LTTT were better in comparison to after conventional heat treatment (CHT)...
April 7, 2018: 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"