Uniaxial Tensile Force Research Articles

Predicting Damage in Notched Functionally Graded Materials Plates through extended Finite Element Method based on computational simulations

Presently, Functionally Graded Materials (FGMs) are extensively utilised in several industrial sectors, and the modelling of their mechanical behaviour is consistently advancing. Most studies investigate the impact of layers on the mechanical characteristics, resulting in a discontinuity in the material. In the present study, the extended Finite Element Method (XFEM) technique is used to analyse the damage in a Metal/Ceramic plate (FGM-Al/SiC) with a circular central notch. The plate is subjected to a uniaxial tensile force. The maximum stress criterion was employed for fracture initiation and the energy criterion for its propagation and evolution. The FGM (Al/SiC) structure is graded based on its thickness using a modified power law. The plastic characteristics of the structure were estimated using the Tamura-Tomota-Ozawa (TTO) model in a user-defined field variables (USDFLD) subroutine. Validation of the numerical model in the form of a stress-strain curve with the findings of the experimental tests was established following a mesh sensitivity investigation and demonstrated good convergence. The influence of the notch dimensions and gradation exponent on the structural response and damage development was also explored. Additionally, force-displacement curves were employed to display the data, highlighting the fracture propagation pattern within the FGM structure.

Influence of mechanical stress on electron transport properties of second-generation high-temperature superconducting tapes

Second-generation high-temperature superconductor (2G HTS) tapes have demonstrated the ability to generate high magnetic fields and critical currents at a wide operating temperature range. In this paper, we study the mechanical properties of 2G HTS tape measured simultaneously with its critical current. The lattice deformations in the tape’s substrate caused by applied mechanical stress were measured by neutron diffraction. In our experiments, the 2G HTS tape was exposed to uniaxial tensile force ranging from 250 to 1100 N at temperature 77 K. The current through the tape was scanned in the range from 22 to 42 A. The experimental results have been obtained in a cryogenic testing chamber for neutron scattering measurements of internal stresses under load with the incorporated HTS current leads. Critical stress is a vital parameter required for the modeling and designing of advanced superconducting magnets and also a variety of different superconducting applications based on 2G HTS tapes.

Elastic Modulus and Flatwise (Through-Thickness) Tensile Strength of Continuous Carbon Fibre Reinforced 3D Printed Polymer Composites.

Additively manufactured composite specimens exhibit anisotropic properties, meaning that the elastic response changes with respect to orientation. Both in-plane and out-of-plane mechanical properties are important for designing purpose. Recent studies have characterised the in-plane performance. In this study, however, through-thickness tensile strength of 3D polymer composites were determined by printing of continuous carbon fibre reinforced thermoplastic polyamide-based composite, manufactured using a Markforged Two 3D printer. This paper discusses sample fabrication and geometry, adhesive used, and testing procedure. Test standards used to determine out-of-plane properties are tedious as most of the premature failures occur between the specimens and the tabs. Two types of samples were printed according to ASTM flatwise tension standard and the results were compared to determine the geometry effect on the interlaminar strength. This test method consists of subjecting the printed sample to a uniaxial tensile force normal to the plane. With this method, the acceptable failure modes for tensile strength must be internal to the structure, not between the sample and the end tabs. Micro-computed tomography (µCT) was carried out to observe the porosity. Surface behaviour was studied using scanning electron microscopy (SEM) to see the voids and the distribution of the fibres in the samples. The results showed consistent values for tensile strength and elastic modulus for Araldite glue after initial trials (with some other adhesives) to determine a suitable choice of adhesive for bonding the samples with the tabs. Circular specimens have higher tensile strength and elastic modulus as compared to rectangular specimens.

Atomic Simulations of Packing Structures, Local Stress and Mechanical Properties for One Silicon Lattice with Single Vacancy on Heating.

The effect of vacancy defects on the structure and mechanical properties of semiconductor silicon materials is of great significance to the development of novel microelectronic materials and the processes of semiconductor sensors. In this paper, molecular dynamics is used to simulate the atomic packing structure, local stress evolution and mechanical properties of a perfect lattice and silicon crystal with a single vacancy defect on heating. In addition, their influences on the change in Young’s modulus are also analyzed. The atomic simulations show that in the lower temperature range, the existence of vacancy defects reduces the Young’s modulus of the silicon lattice. With the increase in temperature, the local stress distribution of the atoms in the lattice changes due to the migration of the vacancy. At high temperatures, the Young’s modulus of the silicon lattice changes in anisotropic patterns. For the lattice with the vacancy, when the temperature is higher than 1500 K, the number and degree of distortion in the lattice increase significantly, the obvious single vacancy and its adjacent atoms contracting inward structure disappears and the defects in the lattice present complex patterns. By applying uniaxial tensile force, it can be found that the temperature has a significant effect on the elasticity–plasticity behaviors of the Si lattice with the vacancy.

Bearing capacity of bolted ball-cylinder joint under uniaxial tensile force

The bolted ball-cylinder (BBC) joint is a new type of joint system for non-purlin grid structures. Since the BBC joints may subject to tensile force in the cantilevered parts of the structure, or under situations where the wind suction dominates, this paper investigates the bearing capacity of the BBC joints under uniaxial tensile force by means of numerical analysis. Firstly, the establishment and verification of the finite element (FE) model is introduced briefly. Then, the parametric studies, considering various dimensions of the hollow cylinder, rectangular tube member, ribbed stiffener, convex washer, and high strength bolts are carried out based on the verified FE model, and the influence of each parameter is analyzed in detail. Finally, the formulae to estimate the bearing capacity of the BBC joint under uniaxial tensile force are obtained by regression analysis. The comparison of the calculation results using the formulae, the numerical and the experimental results shows that the proposed formulae are with satisfactory accuracy and can be applied to practical engineering.

Influence of preparation height and cement space on the fit and retention of computer aided design/computer aided manufacturing zirconia crown

To investigate the effects of preparation height and cement space on the fit and retention of computer aided design (CAD)/computer aided manufacturing (CAM) zirconia crown, and to provide reference for the clinical design and fabrication of CAD/CAM crowns. 3D printing system was used to fabricate resin abutment teeth with convergence angle of 2° and height of 1-3 mm. The models' optical impressions were collected by the three-shape scanner. Then, the cement spaces were set by Cradle CAD/CAM system at 10-50 μm to create an all-ceramic zirconia crown. The fit of the crowns was measured by using silicone rubber interstitial impression method. The retention of the crowns was measured by pull-off test with uniaxial tensile force after the crown was bonded. The data were analyzed by SPSS 22.0 soft-ware. When the preparation height was fixed, the fitness values of different cement space groups have statistical difference (P< 0.05), whereas the retention values of different cement space groups have no statistical difference (P>0.05). The fitness values of different preparation height groups have no statistical difference (P>0.05), and the retention values of different preparation height groups have statistical difference (P<0.05) when the cement space was fixed. No interaction was observed between the cement space and the preparation height (P>0.05). When cradle CAD/CAM system is used to create a full crown in the clinic, the preparation height should be set to more than 3 mm, and the cement space should be set at 30 μm.

Mechanotunable optical filters based on stretchable silicon nanowire arrays

Abstract Nano-structural optical filters embedded in elastomers having high mechanical tunability provide the geometric degree of freedom for selective light manipulation. The active control of spectral information in typical structural optical filters is highly limited due to the substrate rigidity. Herein, we present mechanochromic transmissive optical filters by employing flexible and stretchable polymer-embedded silicon nanostructures. Si-based nanowire arrays (Si-NWAs) have been introduced to exhibit parametric resonance characteristics by controlling the period and/or diameter. Furthermore, the spectral shift phenomenon by increased diffraction efficiency was observed after the application of a uniaxial tensile force, which depends on the period of Si-NWAs with a large index contrast between the silicon nanowire and elastomer. The strain-sensitive properties of tunable Si-NWAs filters induced by light diffraction were calculated by simulation based on wave optics. The spectral tunability and light filtering features were simply demonstrated by stretching the Si-NWAs’ optical filters. Our proposed structure provides potential opportunities for a wide variety of applications, including dynamic color display, visual strain sensor and anti-counterfeiting.

Numerical Analysis of the Perforated Steel Sheets Under Uni-Axial Tensile Force

The perforated steel sheets have many uses, so they should be studied under the influence of the uniaxial tensile load. The presence of these holes in the steel sheets certainly affects the mechanical properties. This paper aims at studying the behavior of the stress-strain engineering relationships of the perforated steel sheets. To achieve this, the three-dimensional finite element (FE) model is mainly designed to investigate the effect of this condition. Experimental tests were carried out on solid specimens to be used in the test of model accuracy of the FE simulation. Simulation testing shows that the FE modeling revealed the ability to calculate the stress-strain engineering relationships of perforated steel sheets. It can be concluded that the effect of a perforated rhombus shape is greater than the others, and perforated square shape has no effect on the stress-strain engineering relationships. The efficiency of the perforated staggered or linearly distribution shapes with the actual net area on the applied loads has the opposite effect, as it reduces the load capacity for all types of perforated shapes. Despite the decrease in load capacity, it improves the properties of the steel sheets.

Evaluation of retention of two implant supported ceramic crowns using two temporary cements

Aim: The purpose of this in vitro study was to evaluate the effect of two temporary cements (Resin based cement and Eugenol Free Zinc oxide cement) on the retention of two titanium implant supported crowns made of (Polymer infiltrated hybrid glass ceramic and Yttrium stabilized tetragonal zirconia).Materials and methods: 20 dummy implants were inserted in epoxy resin blocks. The twenty blocks were divided according to the crown material into two groups (n=10): Group I: VITA ENAMIC™ crowns, Group II: BurxZir™ zirconia crowns. Each group were further sub-divided into two sub-groups (n=5), according to the temporary cement material used (Sub-group A: crowns cemented with DentoTemp™ cement, Sub group B: crowns cemented with Tempbond NE™ cement). The crowns were fabricated with CAD-CAM technology. Each crown had two wings on the mesial and distal surfaces to aid in retention analysis. The crowns were cemented to the titanium abutments and then retention was measured using uni-axial tensile force test.Results: DentoTemp™ cement showed a higher retentive values with both crown materials. The retentive values of the DentoTemp™ temporary cement was significantly higher than those of the Tempbond NE™ cement when used with BruxZir™ Zirconia crowns.Conclusions: Resin based temporary cement showed significantly higher retention results than non-eugenol temporary cement while the difference in crown material showed no significant difference.

Statistical study of ductility-dip cracking induced plastic deformation in polycrystalline laser 3D printed Ni-based superalloy

Ductility-dip cracking in Ni-based superalloy, resulting from heat treatment, is known to cause disastrous failure, but its mechanism is still not completely clear. A statistical study of the cracking behavior as a function of crystal orientation in a laser 3D-printed DL125L Ni-based superalloy polycrystal is investigated here using the synchrotron X-ray microdiffraction. The dislocation slip system in each of the forty crystal grains adjacent to the 300 μm long crack has been analyzed through Laue diffraction peak shapes. In all these grains, edge-type geometrically necessary dislocations (GNDs) dominate, and their dislocation line directions are almost parallel to the crack plane. Based on Schmid’s law, the equivalent uniaxial tensile force direction is revealed normal to the trace of the crack. A qualitative mechanism is thus proposed. Thermal tensile stress perpendicular to the laser scanning direction is elevated due to a significant temperature gradient, and thus locations in the materials where the thermal stress exceeds the yield stress undergo plastic deformation mediated by GND activations. As the dislocations slip inside the crystal grains and pile up at the grain boundaries, local strain/stress keeps increasing, until the materials in these regions fail to sustain further deformation, leading to voids formation and cracks propagation.

Effect of production method on surface roughness, marginal and internal fit, and retention of cobalt-chromium single crowns

Statement of problemNew production methods have been developed for metal-ceramic restorations. Different production methods may show different surface roughness and fit, which may affect retention and long-term success. PurposeThe purpose of this in vitro study was to examine 3 different production methods with regard to surface roughness, marginal and internal fit, and retention of cobalt-chromium alloy single-crown copings. Material and methodsA master abutment of a premolar mandibular tooth preparation with 4-mm height and a 0.6-mm deep 120-degree chamfer finish line with a 12-degree angle of convergence was replicated in die stone and scanned. Thirty-six cobalt-chromium alloy copings were produced using 3 different production techniques. Twelve copings were produced by laser-sintering, 12 by milling, and 12 by milled wax/lost wax. The surface microstructure of 2 copings in each group was analyzed using interferometry. The remaining 10 copings in each group were used to evaluate marginal and internal fit by using an impression material replica method, and retention was evaluated by using a uniaxial tensile force pull-off test. The copings from each test group were cemented with zinc phosphate cement onto resin abutments. Statistical analyses of differences in marginal and internal fit were performed using 1-way ANOVA and the Mann-Whitney U test. Differences in surface topography were analyzed with the Kruskal-Wallis and Mann-Whitney U tests for nonparametric data. Differences in retentive values were analyzed using the Mann-Whitney U test for nonparametric data (all α=.05). ResultsDifferences in surface microstructure were seen. The laser-sintered copings showed increased surface roughness compared with milled and milled wax/lost wax copings. Differences in marginal and internal fit were noted. Laser-sintered showed significantly smaller spaces between coping and abutment than milled wax/lost wax copings (P=.003). At the margins, laser-sintered copings showed significantly smaller spaces than either the milled wax/lost wax group (P=.002) or the milled group (P=.002). At the chamfer, laser-sintered copings showed significantly smaller spaces than milled wax/lost wax copings (P=.005). At the center of the axial walls, laser-sintered copings showed significantly smaller spaces than those in the milled wax/lost wax (P=.004) and milled copings (P=.005). No significant differences were noted between milled and milled wax/lost wax copings (P>.05). No significant differences were detected regarding retentive forces in the pull-off tests (P>.05). ConclusionsLaser-sintered Co-Cr crown copings showed increased surface roughness and better internal and marginal fit than copings produced by milling or milled wax/lost wax technique. However, the crown pull-off tests did not reveal any significant differences.

High surface area carbon black (BP‐2000) as a reinforcing agent for poly[(−)‐lactide

ABSTRACTThe brittle nature and low‐heat distortion resistance of a promising biorenewable thermoplastics, poly((−)‐lactide) (PLA), motivate the investigation of strengthening additives that can address these deficiencies. In our work, a high surface area carbon black (BP‐2000) as well as biobased carbon blacks (hydrochars) were examined as reinforcement agents for PLA. When 1–5 wt % BP‐2000 was added to PLA, the crystallization of PLA was accelerated, resulting in higher crystallinity, tensile strength, and heat resistance. A thermal creep experiment revealed that the composites exhibited no significant deformation after 30 min with 2 N of uniaxial tensile force at 80 °C (above the Tg), whereas neat PLA (with similar thermal history) elongated to 79% after 5 min under the same conditions. PLA–hydrochar composites demonstrated similar brittle behavior to neat PLA. Despite the promising nucleating ability of hydrochars, they displayed low interfacial adhesion with PLA because of their low surface area, resulting in poor energy transfer on stretching. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43926.

Tensional acoustomechanical soft metamaterials.

We create acoustomechanical soft metamaterials whose response to uniaxial tensile stressing can be easily tailored by programming acoustic wave inputs, resulting in force versus stretch curves that exhibit distinct monotonic, s-shape, plateau and non-monotonic snapping behaviors. We theoretically demonstrate this unique metamaterial by considering a thin soft material sheet impinged by two counter-propagating ultrasonic wave inputs across its thickness and stretched by an in-plane uniaxial tensile force. We establish a theoretical acoustomechanical model to describe the programmable mechanics of such soft metamaterial, and introduce the first- and second-order tangential stiffness of its force versus stretch curve to boundary different behaviors that appear during deformation. The proposed phase diagrams for the underlying nonlinear mechanics show promising prospects for designing tunable and switchable photonic/phononic crystals and microfluidic devices that harness snap-through instability.

A study to evaluate the effect of taper on retention of straight and angled implant abutment

Aim: The purpose of this study was to evaluate the effect of taper on retention of copings in straight and angled implant abutment. Materials and Methods: Totally, 10 straight abutments (Adin Israel) of 3° taper and angled abutment of 15° taper with their analogs were used. Twenty castings were fabricated on the abutment that incorporated an attachment to allow removal. Castings were cemented to abutments with provicol (VOCO Germany). A uniaxial tensile force was applied to the crown using an instron machine until cement failure occurred. Results: Data were subjected to Shapiro-Wilk test, and it was found that variables have a normal distribution. Hence, Student's t-test was performed, and P value was found to be 0.00 <0.05. Hence to infer significant statistical difference. Conclusion: The retention of straight abutments was significantly more when compared to angled abutment when cemented with provicol. When using angled abutment, permanent luting agent should be the choice for cementation.

Effect of screw access channel filling materials on uniaxial retentive force of cement‐retained implant restorations

This study aimed to investigate the effect of various abutment screw access channel filling materials on the uniaxial retention of castings cemented onto the abutment using temporary cement. Ten straight, regular platform Esthetic Abutments were used. Fifty castings were divided into five groups and the abutment screw access channels were filled with composite resin (Filtek Z 250), light-cured temporary filling (Clip), temporary filling (Coltosol), polyvinyl siloxane impression material (Elite H-D), or polytetrafluoroethylene (PTFE) tape. Castings were cemented and thermal cycled. A uniaxial tensile force with a cross-head speed of 5 mm/min, was applied to the castings until cement failure occurred. One-way analysis of variance was used to perform intergroup comparisons of the mean uniaxial retentive force (URF) values and Tukey's HSD test was used to determine the group causing the difference. There were statistically significant differences between the mean URF values for the groups (p < 0.01). The mean URF value for the composite resin group was statistically higher than those for the other filling material groups respectively (p < 0.05). The retention of castings cemented to straight implant abutments using non-eugenol temporary cement may be influenced by the screw access channel filling material.

A new fixation method for stick-shaped specimens in microtensile tests: laboratory tests and FEA.

To introduce a new fixation method for stick-shaped specimens for use in microtensile tests and to evaluate the effect of this new method on microtensile bond strength, failure modes, and stress distribution. Flat mid-coronal dentin surfaces were prepared on 12 caries-free human third molars and randomly divided into two groups for testing with two dental adhesives (Adper Single Bond 2 [SB2] and Clearfil SE Bond [SEB]). Following adhesive application and composite buildups, the bonded teeth were sectioned into beams. Sticks from each tooth were then equally divided into two subgroups for microtensile bond testing according to the utilized gripping devices (a flat Ciucchi's jig and the experimental setup). Failure modes were examined with a field-emission scanning electron microscope (FESEM). Three-dimensional models of each gripping device and specimen were developed, and stress distributions were analyzed by finite element analysis (FEA). Statistical significance was set at α = 0.05 RESULTS: Compared to those fixed using a flat Ciucchi's jig, sticks fixed with the experimental setup yielded lower bond strength values (p = 0.021 for SB2 and p = 0.007 for SEB) and more mixed failure patterns (p = 0.036 for both SB2 and SEB). In addition, the experimental setup guaranteed a uniaxial tensile force that was perpendicular to the bonding interface and produced a more uniform stress distribution at the bonding interface. An experimental setup for fixing microtensile sticks was proposed that was designed to provide a uniform stress distribution at the adhesive interface. FEA and failure mode analysis confirmed such uniform distribution, thus supporting the validity of the bond strength results obtained with this new fixture design.

2D WAXS/SAXS study on isotactic propylene-1-butylene random copolymer subjected to uniaxial stretching: The influence of temperature

The influence of temperature on the crystallization process of isotactic propylene-1-butylene (P–B) random copolymer with low comonomer concentration subjected to uniaxial tensile force was studied in-situ by using synchrotron-based wide- and small-angle X-ray scattering techniques (WAXS/SAXS). Data analysis was performed on the whole-pattern base. P–B copolymer was stretched at three temperatures, i.e., 100 °C, 60 °C and 25 °C. Before stretching, the static sample contained both γ- and α-phase of isotactic polypropylene (iPP) homopolymer, with the γ-phase being the dominant crystal modification. When subjected to uniaxial stretching, γ-phase adopted a tilted cross-β configuration, with the c-axis forming a tilting angle with respect to the fiber axis at all temperatures. At 100 °C and 60 °C, γ-phase was transformed to α-phase with parallel orientation of polymer chains. Daughter lamellae of the α-phase were observed at 100 °C but not at 60 °C. At room temperature, large lamellar crystals could not be formed due to strong tensile force applied to the polymer network. Low temperature stretching was featured with the formation of mesomorphic phase which was composed of tiny β-form crystals and of about 50% of oriented amorphous phase. The c-axis of the β-form crystal was in parallel to the fiber axis. The crystals were so small that no ordered texture was observed at the length scale of nanometers.

Investigation of Electrical Characteristics of Gold Nanowire under Tensile Test

In this study, the electrical characteristics of gold nanowire (NW) under external tensile force were experimentally investigated. Experiments were carried out with a self-developed nanomanipulator inside the vacuum chamber of a scanning electron microscopye. A resistivity of for an individual gold NW was first obtained with the nanomanipulation system when no tensile force is applied, approximately 4.36 times larger than that of bulk gold. The results agree with the works of previous investigations. The electric characteristics of gold NWs under uni-axial tensile force was then investigated via the nanomanipulator. Experimental results show that the resistivity of gold NWs decreases as the applied tensile force increases, while the conductivity of the NWs as well as the mobility of electrons increases as the force increases. This indicates that the electrical characteristics of gold NWs are indeed affected by the external tensile forces applied to it.

A method for tensile tests of biological tissues at the mesoscale

We describe a new technique for determining the tensile properties of biological tissues at the mesoscale. The procedure uses a calibrated magnetic interaction between a steel bead attached to the sample and a permanent magnet to apply a uniaxial tensile force, along with a simple video assay to monitor the sample extension and thus the strain. Our method fills a significant gap in the accessible range of both forces and strains and is useful for forces in the micro and milli-Newton range, and displacements in the range of hundreds of microns with strains of up to 200%. We give two examples of the mechanical characterization of tissues using our technique, employing it to characterize the elastic modulus of tubular and membraneous embryonic tissues from the chick.

J032011 FIB加工されたナノ構造体の力学特性評価技術の開発

In this article, the development of mechanical characteristics evaluation technique for FIB-processed nanostructures is described. We designed the on-chip tensile testing device, which consists of a nano-specimen, electrostatic actuator for stretching the specimen, and capacitance sensor for measuring tensile displacement. A theoretical resolution of 1 nm in tensile displacement was achieved. The uniaxial tensile force was derived using the spring constant of suspended beams with theoretical resolution of 15 nN. In addition, we developed a new nano-testing technique that is the combination of on-chip tensile testing device and nano-sampling technique using FIB. By using the technique, the Young's modulus of Si nanowire was measured to be 168.8 GPa, which is close to the ideal value of SCS (001)[110]. The tensile strength was 8.3 GPa, indicating that there is a size effect on the strength.