Longitudinal Tensile Force Research Articles

The Micromechanical Environment of the Impinged Achilles Tendon.

Although tendon predominantly experiences longitudinal tensile forces, transverse forces due to impingement from bone are implicated in both physiological and pathophysiological processes. However, prior studies have not characterized the micromechanical strain environment in the context of tendon impingement. To address this knowledge gap, mouse hindlimb explants are imaged on a multiphoton microscope, and image stacks of the same population of tendon cells are obtained in the Achilles tendon before and after dorsiflexion-induced impingement by the heel bone. Based on the acquired images, multiaxial strains are measured at the extracellular matrix (ECM), pericellular matrix (PCM), and cell scales. Impingement generated substantial transverse compression at the matrix-scale, which led to longitudinal stretching of cells, increased cell aspect ratio, and enormous volumetric compression of the PCM. These experimental results are corroborated by a finite elementmodel, which further demonstrated that impingement produces high cell surface stresses and strains that greatly exceed those brought about by longitudinal tension. Moreover, in both experiments and simulations, impingement-generated microscale stresses and strains are highly dependent on initial cell-cell gap spacing. Identifying factors that influence the microscale strain environment generated by impingement could contribute to a more mechanistic understanding of impingement-induced tendinopathies.

Tensile strength of adhesives in peripheral nerve anastomoses: an in vitro biomechanical evaluation of four different neurorrhaphies

BackgroundThe fundamental prerequisite for prognostically favorable postoperative results of peripheral nerve repair is stable neurorrhaphy without interruption and gap formation.MethodsThis study evaluates 60 neurorrhaphies on femoral chicken nerves in terms of the procedure and the biomechanical properties. Sutured neurorrhaphies (n = 15) served as control and three sutureless adhesive-based nerve repair techniques: Fibrin glue (n = 15), Histoacryl glue (n = 15), and the novel polyurethane adhesive VIVO (n = 15). Tensile and elongation tests of neurorrhaphies were performed on a tensile testing machine at a displacement rate of 20 mm/min until failure. The maximum tensile force and elongation were recorded.ResultsAll adhesive-based neurorrhaphies were significant faster in preparation compared to sutured anastomoses (p < 0.001). Neurorrhaphies by sutured (102.8 [cN]; p < 0.001), Histoacryl (91.5 [cN]; p < 0.001) and VIVO (45.47 [cN]; p < 0.05) withstood significant higher longitudinal tensile forces compared to fibrin glue (10.55 [cN]). VIVO, with △L/L0 of 6.96 [%], showed significantly higher elongation (p < 0.001) compared to neurorrhaphy using fibrin glue.ConclusionWithin the limitations of an in vitro study the adhesive-based neurorrhaphy technique with VIVO and Histoacryl have the biomechanical potential to offer alternatives to sutured neuroanastomosis because of their stability, and faster handling. Further in vivo studies are required to evaluate functional outcomes and confirm safety.

EFFECT OF BACK PRESSURE DURING DIRECT PRESETTING OF ALLOY LBTPN D16T

Pipes made of high-strength aluminum alloys with protector thickeners in the middle and at the ends are actively used in the construction of wells for oil and gas. Their light weight and sufficient strength make it possible to build wells of greater depth from lower lifting capacity installations. In addition, aluminum alloy pipes of keyless construction are widely used in cases where there is a high content of carbon dioxide and hydrogen sulfide. This design and material make it possible to significantly increase the service life of pipes in aggressive, corrosive environments. In order to increase the production speed of pipes, it is proposed to use the technology of direct compression with back pressure. You can simulate the manufacturing process using this technology of LBTPN (alloy drill pipe of increased reliability) using a specialized software complex DEFORM, which was done. These aluminum pipes are used in the development of ultra-deep gas and oil wells, as well as horizontal and inclined extended reach wells. LBTPNs were also used in the drilling of ultra-deep Kola, Kryvyi Rih, and Ural wells. It is possible to use compressed pipes with back pressure if the design depth of the well is more than 3000 m. During pressing in the plastic deformation focus, stress transformation is observed: normal growth and drop of tangents and, therefore, a decrease in their total impact; increased level of hydrostatic pressure, all components of deformations and, therefore, also their total impact. Unlike the non-backpressure process, when present and under its action in the gage zone, there is a significant decrease in longitudinal tensile forces, as a result it is possible to carry out the process with higher values of alloy flow rates. Also, pipes made of aluminum alloys of a lock-free design are widely used in cases where there is a high content of carbon dioxide and hydrogen sulfide. This design and material can significantly increase the service life of pipes.

Analysis of the roll imprint on the cross-sectional area of hot rolled wire rod by frequency spectroscopy

This work presents an approach for analysing the sensor data of an eddy-current based cross-sectional area measurement for hot rod and wire steel in an innovative manner and for approximating the influence on the forward slip by longitudinal tensile forces between the mill stands. The method is based on frequency spectroscopy of the cross-sectional area of the rolled stock. The measurement data of three sensors already implemented in two hot rolling mills is used in order to obtain information out of the roll imprint on the cross-sectional area. Since measurement data from two measuring sites and from three sensors are evaluated, this allows statements to be made about the reliability and reproducibility of the measurement and shows that the method can be used for different rolling blocks such as 3-roll and 2-roll blocks. In addition, a mathematical model is presented which allows conclusions to be drawn about possible causes for certain characteristics in the measured frequency spectrum of the cross-sectional area.

Mechanical and friction properties of agricultural plastic film during autumn harvest period of cotton in Xinjiang, China.

Agricultural plastic films have caused serious plastic pollution. There are many studies that consider mechanical recycling an appropriate system for the recovery of post-consumption agricultural mulch film. The recovery effect of plastic film depends on the mechanical properties, the level of dirtiness of the post-consumption film, and the recycling process itself. In this study, the mechanical properties of four types of polyethylene plastic films with a thickness of 8, 10, 12, and 10μm, weather-resistant, commonly used in Xinjiang cotton fields, were tested. As well as the friction coefficient between the film and soil, the cotton stalk, boll shell, and leaf with different moisture contents were measured. Then, the self-propelled straw chopping and residual film recycling combined machine collected the four types of mulch films. The results showed that the longitudinal mechanical properties of the plastic film were greater than the transversal ones, with the exception of the nominal tensile strain at break, and the tensile characteristics of the mulching film covered with soil were greater than those without soil. The dynamic or static friction coefficient between the film and the contact material had a linear relationship with the moisture content of the material. During the recycling operation, the better the mechanical properties of the plastic film, the higher the pick-up rate of the mulch film. The maximum longitudinal tensile force of 12-μm plastic film was 3.42 N, and the nominal tensile strain at break was 303.09%. The pick-up rate reached more than 93% when the 12-μm plastic film was recovered in autumn, which effectively reduced the residue of plastic film coverage in the current year. Moreover, the more soil that was present on the much film, the greater the soil content of the recycled film roll, and the stalk content also increased, but the change was small. The research provides a reference for the mechanical and the friction features of agricultural plastic film in Xinjiang, and provides a theoretical basis for the formulation of standards for film thickness and mechanical properties, as well as the design and optimization of a residual film collecting machine in the cotton field.

Evaluation of fibrin, cyanoacrylate, and polyurethane-based tissue adhesives in sutureless vascular anastomosis: a comparative mechanical ex vivo study

The stability of a microvascular anastomosis is an important prerequisite for successful tissue transfer. Advances in tissue adhesives are potentially opening new avenues for their use in sutureless microsurgical anastomosis, however they have not yet gained clinical acceptance. In this ex vivo study, a novel polyurethane-based adhesive (PA) was used in sutureless anastomoses and its stability compared with that of sutureless anastomoses performed with fibrin glue (FG) and a cyanoacrylate (CA). Stability was assessed using hydrostatic (15 per group) and mechanical tests (13 per group). A total of 84 chicken femoral arteries were used in this study. The time taken to create the PA and CA anastomoses was significantly faster when compared to the FG anastomoses (P < 0.001): 1.55 ± 0.14 min and 1.39 ± 0.06 min, respectively, compared to 2.03 ± 0.35 min. Both sustained significantly higher pressures (289.3 mmHg and 292.7 mmHg, respectively) than anastomoses using FG (137.3 mmHg) (P < 0.001). CA anastomoses (0.99 N; P < 0.001) and PA anastomoses (0.38 N; P = 0.009) could both withstand significantly higher longitudinal tensile forces compared to FG anastomoses (0.10 N). Considering the background of an in vitro study, the PA and CA anastomosis techniques were shown to be similar to each other and superior to FG, due to their stability and faster handling. These findings need to be validated and confirmed in further in vivo studies.

Dynamic analysis and vibration control for overhead hoist transport

The OHT system is a transport device used for intra- or inter-plant transport in a fab or other factory, the load-bearing part of the goods stored under the trolley generates longitudinal vibration and lateral oscillation due to inertia force When the OHT in the air starts or stops. Firstly, the trolley dynamic model under the action of lateral thrust and longitudinal tensile force need to be established. secondly, the coupling analysis of horizontal oscillation and longitudinal oscillation on the model is carried out. Thirdly, aiming at the lateral swing and longitudinal vibration of the carriage, a double closed-loop vibration control strategy with tension control as inner loop and speed control as outer loop and carry out the simulation analysis of longitudinal vibration control is proposed. In the experiment of the ground trolley, the control strategy is applied. The simulation and experimental results show that the control method can quickly restrain the longitudinal vibration of the trolley bearing plate, reduce the pulling force of the trolley on the lifting steel belt, and avoid the large displacement of the bearing plate in the air.

Numerical simulation of deformations of a specimen of a composite helicopter blade as part of a resonant vibration set-up

To determine the fatigue life of the tail rotor blade of a helicopter made of polymer composite materials (CM), a method of fatigue testing of the specimens of the blade with accompanied numerical modeling of the deformed state has been developed. The tests are carried out on a resonant vibration set-up, with simultaneous reproduction of a forcing harmonic transverse force and a constant longitudinal tensile force. The tests are carried out by a vibration loading mode equivalent in fatigue damage, which includes one level of variable load in the thrust plane and in the plane of rotation. The equivalent mode is formed based on the variable loading spectrum of the blade, which is obtained from the results of flight measurements of the loads on the tail rotor, as well as the repeatability of the expected operating conditions of the helicopter. The tests are accompanied by computational and experimental studies, which include finite element calculation of the stress state and modal analysis of the standard blade and the test specimen, as well as the strain measuring of the structure. According to the results of the research, the vibration loading modes are corrected.

Full-scale test on seismic performance of circumferential joint of shield-driven tunnel

A shield-driven tunnel is deformed along the longitudinal direction when subjected to seismic loadings; the circumferential joint is the key position of the shield-driven tunnel when such longitudinal deformation occurs. In this study, the variations of the internal forces (including both axial forces and bending moments) in the longitudinal direction of the tunnel are analyzed through a numerical method based on the longitudinal equivalent continuous model (LECM). The results show that the internal forces of the tunnel are mainly an axial force caused by longitudinal excitation, and a vertical bending moment caused by transverse excitation. Based on the stress distribution of the circumferential joint, a full-scale test is conducted, and the test results are compared with those obtained by a refined numerical model with 16 segmental rings. It is shown that the variation of the opening and bolt strain of the circumferential joint follows that of the internal force. When the tunnel is subjected to longitudinal tensile forces or bending moments, the distribution rules for the bolt stress at the position of the largest opening are essentially the same. Moreover, the distribution characteristics of the concrete strain on the segment surface at the position of the largest opening are essentially the same. The maximum tensile strain appears on the outer surface of the sleeve side segment. However, the maximum compressive strain appears on the inner surface of the hand hole side segment. The maximum principal stress and damaged plasticity of the segment generally appear near the sleeve and hand hole, and have a limited influence on the segment surface. Finally, a failure test shows that the segment becomes damaged before the bolt yield, with more severe damage occurring in the sleeve side segment.

Mechanical strength and hydrostatic testing of VIVO adhesive in sutureless microsurgical anastomoses: an ex vivo study

Conventional anastomoses with interrupted sutures are challenging and inevitably associated with trauma to the vessel walls. The goal of this study was to evaluate a novel alternative adhesive-based suture-free anastomosis technique that uses an intraluminal stent. Overall, 120 porcine coronary vessels were analyzed in an ex vivo model and were examined for their mechanical (n = 20 per cohort) and hydrostatic strength (n = 20 per cohort). Anastomoses were made using the novel VIVO adhesive with an additional intraluminal nitinol stent and was compared to interrupted suture anastomosis and to native vessels. Sutureless anastomoses withstood pressures 299 ± 4.47 [mmHg] comparable to native vessels. They were performed significantly faster 553.8 ± 82.44 [sec] (p ≤ 0.001) and withstood significantly higher pressures (p ≤ 0.001) than sutured anastomoses. We demonstrate that the adhesive-based anastomosis can also resist unphysiologically high longitudinal tensile forces with a mean of 1.33 [N]. Within the limitations of an in vitro study adhesive-based suture-free anastomosis technique has the biomechanical potential to offer a seamless alternative to sutured anastomosis because of its stability, and faster handling. In vivo animal studies are needed to validate outcomes and confirm safety.

Strain analysis of Moso bamboo (Phyllostachys pubescens) subjected to longitudinal tensile force

This study used digital image correlation (DIC) to perform a strain analysis of Moso bamboo (Phyllostachys pubescens) in the tangential section subjected to longitudinal tensile force to compare samples from outer/inner position of the culm wall. Simultaneously, an electrical resistance strain gauge (SG) was used to measure the strain profile for comparison with the strain analysis using DIC. During loading, the rate of the longitudinal strain between different positions was significantly different. As the load time increased, there was no difference in the rate of the transverse strain between the outer and inner samples, while the rate of the longitudinal strain for the inner sample was higher than that for the outer sample. Additionally, DIC showed that the longitudinal direction showed a relatively homogeneous strain contour compared to the transverse direction. Furthermore, the result indicated that the Poisson’s ratio was dependent on the positions of the bamboo in the radial direction of the culm wall. Using SG recording as a reference, the DIC revealed appropriate strain behavior of bamboo in terms of longitudinal and transverse strains within full-field area. Therefore, the DIC recording may help to characterize strain deformation on the bamboo during the application of a tensile force.

Corroded pipelines subjected to an internal pressure plus a longitudinal tensile force Part 1: The CCD equation

Corroded pipelines subjected to an internal pressure plus a longitudinal tensile force Part 1: The CCD equation

Corroded pipelines subjected to an internal pressure plus a longitudinal tensile force part 2: Comparison of CCD equation results and laboratory tests results

Corroded pipelines subjected to an internal pressure plus a longitudinal tensile force part 2: Comparison of CCD equation results and laboratory tests results

Analysis of the mechanical properties of double arrowhead auxetic metamaterials under tension

In order to study the deformation behavior of double arrowhead (DAH) auxetic metamaterials under different forces with different directions as well as the effects of the geometry parameters on the Poisson's ratio, this paper assembled an advanced researching method by combining the industrial design of SolidWorks software, the finite element analysis of Abaqus software and three-dimensional printed technology. Results show that the DAH structure expanded in the direction perpendicular to the force first and contracted with the strain increasing when it was pulled by the uniaxial force, no matter which direction the force is applied. Besides, the auxetic effect of the DAH structure under the tensile force in the X direction is longer than that under the tensile force in the Y direction. It is more resistant to compression when the DAH structure is subjected to transverse tensile forces than when it is subjected to longitudinal tensile forces. The angle of the V-shaped short truss has a significant impact on the negative Poisson's ratio of the DAH structure, while the angle of the V-shaped long truss angle has little influence on its auxetic performance. Specifically, the smaller the angles, the better the auxetic effect.

Role of transverse joints in regulation of the reinforced concrete face stress-strain state

Introduction. Deals with the results of studying effectiveness of arranging transverse joints in the face as the means of regulation of its stress-strain state. At present reinforced concrete faces are constructed without being cut height-wise and transverse joints may be arranged only at the end of the dam construction stages. This is validated by the fact that experience in construction of flexible (discontinuous) faces has not demonstrated the required level of safety of this structural design. However, in the dams of the up-to-date structural designs, maintaining the face integrity is not guaranteed: cracks appeared in reinforced concrete faces at a number of high dams. Formation of cracks in faces should be attributed to presence of tensile stresses, whose values exceed concrete tensile strength. To prevent seal failure of the seepage-control element it is feasible to provide arrangement of the transverse joint in the face section where tensile stresses may be expected. Materials and methods. The studies were conducted on the example of a 100 m high dam with the aid of numerical modeling. Rockfill was considered as a lineally deformed material, but computations were conducted for a wide range of the soil linear deformation modulus: from 60 to 480 МPа. Steel reinforcement was considered in the face. Transverse joints were modelled with the aid of contact finite elements. Results. By the results of numerical modeling the tensile stresses appear in the uncut face due to bending deformations and deformations of longitudinal extension. The most hazardous is the face lower section. At this section the longitudinal tensile force and considerable moment are acting. Transverse joints are feasible to be arranged in this particular section of the face. Conclusion. It was revealed that the main positive effect of the transverse joint arrangement is in decreasing the value of longitudinal tensile force perceived by the face. Impact of the transverse joint on bending moments has a local effect and covers the section of the limited length. Moreover, at arranging joints the values of bending moments may increase. We may recommend arrangement of a transverse joint in the face which is parallel to the perimeter joints only in the face lower part which is subject to longitudinal deformation.

Detection of initial level of Brillouin frequency shift in optical fibres of different types

The paper presents results of researches of the hyper-acoustic wave velocity on characteristics of the optical fiber core. The values of Brillouin frequency shifts for various types of optical fibers at room temperature and without longitudinal tensile force are presented. Database of profiles of the Mandelstam – Brillouin backscattering spectrums for fibers of different kinds and manufacturers allows one to classify the optical fibers in the optical cables and detect “problem” sections of fiber optical communication line.

A Determination of the Initial Level of the Brillouin Frequency Shift in Optical Fibers of Different Kinds

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Tail Component Qualification For the EU ITER PF Coils

The ITER poloidal field (PF) magnet system is composed of six circular coils, consisting of winding packs (WP) made up from a stack of double pancakes (DP) wound of NbTi cable-in-conduit superconductor. The largest coil has a diameter of 24 m, the heaviest weighs 400 ton, and they are designed to produce a total magnetic energy of 4 Giga Joules at a maximum magnetic field of 6 T for 30 000 inductively driven plasma pulses. The ends of the conductors (in the outer-most coil turns) of the top and bottom DP are coil terminations, which are connected to the superconducting bus bars of the feeders, these conductors exit being one of the weakest structural points of the coils. The main function of the tail is to reinforce this region by linking the outer-most termination to the last-but-one turn, thus guaranteeing the transfer of longitudinal tensile force, through an electrically insulated mechanical connection featuring a fiberglass strap. The PF coils are subject to electromagnetic forces induced from their own magnetic field and the magnetic field generated from the rest of the ITER magnet system, the thermal stresses during cooldown and warmup cycles and dc/ac high-voltage levels. Therefore, the tail components shall withstand these conditions while staying within the geometrical boundaries imposed by the conductor dimensions, in order to avoid any protrusion on the WP surface. This paper aims to describe the adopted solution throughout its lifecycle, from the design validation, by the electromagnetic and mechanical analyses, to the design qualification of the set of imposed requirements through the manufacture, and testing of a set of full-size mock-ups.

Auxeticity in nano/microtubes produced from orthorhombic crystals

A solution for the tension and torsion problems for the curvilinearly anisotropic nano/microtubes made of orthorhombic crystals in the framework of the Saint-Venant’s approach is given. We find that the number of partial auxetics among the tubes is twice as frequent among the rectilinearly anisotropic crystals, at the same time about one third of 136 orthorhombic crystals are auxetics. It is shown that the torsion causes extension of the nano/microtubes even in the absence of a longitudinal tensile force. This Poynting’s effect substantially depends on the chiral angle, and in particular, it disappears when the chiral angle vanishes. We also investigate an inverse Poynting’s effect when the extension of the nano/microtubes is accompanied by their twisting. It is shown that the signs of Poynting’s effect and Poisson’s ratio are changed several times with the change of the chiral angle.

Discussion of “Column Supported Embankments with Geosynthetic Encased Columns: Validity of the Unit Cell Concept” [Geotechnical and Geological Engineering 33 (2015) 425–442

The authors present numerical analyses of an embankment underlain by geosynthetic reinforcement and supported by geosynthetic encased columns (GRCSE). In the last part of the paper, the transverse and longitudinal tensile forces in the geosynthetic reinforcement, which underlays the embankment, are compared using a 3-d strip model and the Unit-Cell concept, both in a 3-d model and in a 2-d axisymmetric model. The results of both Unit-Cell models are very similar. The authors show that the Unit-Cell models are not able to capture the transverse force (Tx), which seems obvious, nor the longitudinal force (Ty), which may not be so obvious. The discusser would like to explain that in the authors’ case the longitudinal force (Ty) is not properly captured by the Unit-Cell models because of the ‘‘socalled’’ Poisson effect. A measure of this effect is the Poisson’s ratio (m = -ey/ex) (Fig. 1). In the 3-d strip model, Tx is notably higher than in the Unit-Cell models, as expected. The authors use a Poisson’s ratio of m = 0.3 for the geosynthetic reinforcement, and then, the higher value of Tx causes an additional tensile force in the perpendicular direction (Ty) because of the Poisson effect. Assuming plane strain conditions in the longitudinal direction (ey = 0), ey 1⁄4 0 1⁄4 1 E ry mrx 1⁄4 1 E Ty t m Tx t ð1Þ