Tensile Test Method Research Articles

Substantive Dimethicone-Based Mucoadhesive Coatings

It is challenging to deliver therapeutics in the oral environment due to the wet surfaces, the nature of the mucosa and the potential for saliva washout. In this study, the development of a mucoadhesive dimethicone-based oral carrier system for adhesion to the hard tissue and mucosa in the mouth was examined. This study reports the viscosity and mucoadhesion of dimethicone based polymer blends. The viscosity of the materials was measured using a rheometer. The mucoadhesion of these materials was determined as the work of adhesion and peak tack force using the tensile test method with a texture analyzer. Materials were prepared with either calcium and phosphate salts or sodium fluoride as potential therapeutics for promoting remineralization and treating dentin hypersensitivity by mechanical occlusion. Scanning electron microscopy was used to look at mineral deposition on the surface of dental hard tissue after the application of the dimethicone-based formulations. The results of this study confirm the potential for using these dimethicone-based materials as mucoadhesive therapeutic delivery systems in the oral environment.

Flow behaviors of various metals under tensile load

Abstract The influence of flow behaviors on the results of finite element (FE) analyses of metal-forming processes is dominant, even though it varies with strain hardening and softening phenomena. However, obtaining a flow curve with sufficient accuracy is not easy, particularly at large strains. Among various well-known methods of obtaining flow curves, tensile testing-based method is effective to obtain flow curves at large strains at room temperature. It is believed that the strain hardening behavior at large strains during the tensile test was not fully known. In this study, the flow curves, previously obtained using the combined tensile test and finite element method (FEM) approach, are classified as four categories, including monotonic strain hardening function, double-curvature strain hardening function, strain hardening-perfectly-plastic function, and perfectly-plastic-strain softening function. The tensile test characteristics of each type are investigated using its FE predictions, revealing that the specific type of a material can be identified by the tensile test.

Which tendon graft to choose for anatomical ligament reconstruction in chronic lateral ankle instability? A biomechanical study

BackgroundThe need for anatomic lateral ligament reconstruction of the ankle continues to grow. This procedure usually requires a gracilis autograft or in some cases an allograft. Siegler et al. reported the mechanical characteristics of the collateral lateral ligaments of the human ankle: 231 ± 129 N for the ATFL and 307 ± 142 N for the CFL.The objective of this study was to evaluate the mechanical properties of different tendon grafts available for ATFL and CFL reconstruction. We hypothesized that the properties of the tested grafts are not inferior to the published values of those of the original ligaments on the lateral side of the ankle. MethodsThis was a comparative biomechanical study using 6 cadaver specimens (108 grafts): The biomechanical properties of nine types of grafts were determined using validated tensile testing methods: Gracilis, SemiT, EHL, FHL, Plantaris, Peroneus longus and brevis, TA and TP.The main outcome measure was the comparison of the mechanical properties of each single-stranded tendon with each other and with the known values ​​for the ATFL and CFL, during a uniaxial static rupture test. ResultsThe mean load to failure for the gracilis was 257.5 ± 52.9 N. The groups had similar mean values in terms of the maximum load that they could withstand before failing except for the plantaris (137.9 ± 33.7 N) which was statistically lower than all other tested tendons (p < 0,01).The mean load to failure values of the grafts tested were equal or higher than that of the ATFL and CFL reported by Siegler et al. [14]: 231 ± 129 N for the ATFL and 307 ± 142 N for the CFL, while the grafts tested here had mean failure load between 258 ± 53 N and 464 ± 136 N. ConclusionThe gracilis, peroneus longus/brevis, EHL, FHL, TA, TP and semiT are legitimate grafts for combined ATFL and CFL reconstruction in the ankle. These tendons have mechanical properties (load to failure, maximum strain at failure and stiffness) that are equal to or higher than the native ligaments on the lateral side of the ankle, except the plantaris. Clinical relevanceThis study validates the current use of the gracilis autograft for the anatomical reconstruction of the ATFL and CFL, and even provides proof that other tendons would be suitable for this anatomical reconstruction of the lateral ankle ligament by auto or even allograft under certain conditions. Level of evidenceDescriptive laboratory study.

Digital Representation of Materials Testing Data for Semantic Web Analytics: Tensile Stress Relaxation Testing Use Case

This study aims to represent an approach for transferring the materials testing datasets to the digital schema that meets the prerequisites of the semantic web. As a use case, the tensile stress relaxation testing method was evaluated and the testing datasets for several copper alloys were prepared. The tensile stress relaxation testing ontology (TSRTO) was modeled following the test standard requirements and by utilizing the appropriate upper-level ontologies. Eventually, mapping the testing datasets into the knowledge graph and converting the data-mapped graphs to the machine-readable Resource Description Framework (RDF) schema led to the preparation of the digital version of testing data which can be efficiently queried on the web.

Influence of dimensional deviation and thickness non-uniformity on the small-size specimen tensile results of CLF-1 steel

Tensile testing of small-size specimens has been widely used to evaluate the influence of neutron irradiation on the mechanical properties for structural materials of fusion reactors. In recent years, researchers have been trying to standardize small-size specimen tensile test method. In the present paper, we have investigated the influence of dimensional deviation and thickness non-uniformity on the tensile results of small-size specimen by both experiments and finite element simulations, based on one of the candidate structural materials of fusion reactor, i.e. CLF-1 steel. It was found that under the conditions of small grain size, small metallurgical defect size and suitable specimen preparation, the tensile results of SS-J3 specimen could be close to the results of large-size specimen. Slightly higher yield and ultimate strengths for small specimens may be caused by the surface treatment of the wheel grinding. The repeatability of ultimate strength was better than that of yield strength, and the repeatability of elongation was worse than that of strength. For tensile tests on eight SS-J3 specimens, the maximum difference in total elongation was about 3 %. With ±0.1 mm deviation of thickness and parallel width, the maximum variation in total elongation was about 1.8 %. The ductility properties were sensitive to specimen's thickness non-uniformity, the measured uniform and total elongations would obviously decrease even with 0.01 mm thickness non-uniformity.

Optimized Tensile Test Method for Assessing the Performance of CFRP Grids under High-Temperature Exposure

Optimized Tensile Test Method for Assessing the Performance of CFRP Grids under High-Temperature Exposure

A digital-twin driven Split Hopkinson bar layout for the tensile characterization of thin, low impedance, sheet-like materials

The Split Hopkinson or Kolsky bar is one of the most popular devices when it comes to the mechanical characterization of material samples under high strain-rates. While testing of high impedance materials, such as metal alloys, is relatively straight forward, samples with low impedance pose certain challenges. The present work focuses on the detailed implementation of a high strain-rate tensile testing method for thin, low impedance, sheet-like materials by using the Split Hopkinson test principle. In order to find a suitable Split Hopkinson setup a digital twin was created using explicit finite element methods. With the help of the digital twin, the design of the transmission bar and the sample holders including the friction liners were explored. The numerical model indicated, that a hollow transmission bar with a moderate tapering (hollow bar 1.0) is suited for the characterization of low impedance materials over a wide strain-rate range. Furthermore, this setup has to be combined with an asymmetrical sample holder configuration (heavier on the incident side and lighter on the transmission side) and aluminum friction liners to return accurate results. This numerically derived setup was validated against experimental tests on paper, representative of low impedance, sheet-like materials.

EVALUATION OF SUPERPLASTIC PROPERTIES OF AA7075 ALUMINUM ALLOY SHEET FABRICATED BY THERMOMECHANICAL PROCESSING

The superplastic forming (SPF) process is the large plastic deformation ability of metals and alloys. However, SPF ability can only be achieved under certain conditions including ultrafine grain (UFG) microstructure, high temperature, and very small strain rate. In this work, the high-strength aluminum alloy AA7075 was selected for the experimental process due to its outstanding industrial application. First, thermomechanical processing (TMP) is performed to create a fine stable grain size for the studied alloy. The UFG microstructure was obtained after TMP with an average grain size of about 10 μm. Subsequently, the tensile test method and the bulging free-forming (BFF) method were used to evaluate the superplastic properties of the AA7075 aluminum alloy sheet fabricated by TMP. These two methods are performed at temperatures of 500ºC and 530ºC with strain rates from 10-4 (s-1) to 10-3 (s-1). The relative elongation and the strain rate sensitivity are the evaluation criteria. At the temperature of 530ºC and strain rate of 10-3 (s-1), the maximum relative elongation and flow stress were achieved at 280% and 7.6 MPa, respectively. The value of the coefficient m ranges from 0.3 to 0.6. The obtained results confirm the SPF properties of the aluminum alloy sheet AA7075.

Effect of Chain Orientation on Coupling of Optical and Mechanical Anisotropies of Polymer Films

Polymer films have broad applications in different industries with specific requirements for their optical and mechanical properties. In mass production, processing conditions during film formation that apply forces and motions in various directions to the film tend to manifest preferred molecular chain orientation in the film microstructure, which unavoidably produces optical and mechanical anisotropies. In this paper, we investigate the effect of such macromolecular orientations on the optical and mechanical anisotropies of several polymer films, including polystyrene, poly(methyl methacrylate), poly(ethylene terephthalate), poly(ethylene naphthalate), poly(ether ether ketone), poly(ether sulfones), poly(ethylene chlorotrifluoroethylene), poly(phenylsulfone), and polycarbonate, at temperatures well below their respective glass transitions (Tg). The film mechanical responses, including elasticity, yielding, and post-yield behaviors, were obtained for the in- and out-of-plane directions utilizing tensile and nanoindentation testing methods, respectively. In addition, the net chain orientation within the films was evaluated by birefringence through analyzing the film optical refractive indices, which were verified and complemented by wide-angle X-ray scattering (WAXS) measurements. The results reveal a considerable quantitative correlation between the birefringence and the degree of elastic anisotropy and a qualitative correlation between the chain orientation and the film post-yield tensile instability (necking). These observations corroborate the interrelationship between the microstructure of polymer films and their optical and mechanical properties. In addition, they emphasize that process conditions can be selected to tune the optical and mechanical anisotropies to best serve the material performance in specific devices. We also propose an empirical equation to approximate the out-of-plane film stiffness based upon the optical and in-plane mechanical properties.

Dynamic tensile characteristics of elliptically shaped Ni8Ti9Cr1 rings

Thin-walled tubes with elliptically shaped annular sections are widely applied in fuel ducts and exhaust pipes. However, the tensile mechanical properties of these structures have remained elusive due to the lack of accurate testing methods. This study aims to fill this gap by establishing circumferential tensile testing methods for static and dynamic conditions by employing a split Hopkinson tensile bar and an electronic universal tensile machine. The quasistatic and dynamic tensile characteristics of two distinct elliptically shaped Ni8Ti9Cr1 rings with different aspect ratios were investigated at room temperature, revealing a significant loading rate effect. The tensile curves exhibited considerable fluctuations, which diminshed as aspect ratios decreased. These fluctuations were attributed to stress waves propagating back and forth between the specimen, the clamp, and the bars, causing superimposition. The Johnson‒Cook (JC) model was established based on the experimental results and then incorporated into the finite element model to gain deep insights into the mechanical responses of the Ni8Ti9Cr1 rings under tension. Our findings reveal that dynamic tensile testing of elliptically shaped Ni8Ti9Cr1 rings induces a complex stress state, which leads to nonuniform necking effects and structural vibrations, revealing complex behaviors previously unexplored. This investigation significantly advances the understanding of quasistatic and dynamic tensile responses in elliptically shaped ring structures, shedding light on their mechanical intricacies across varying conditions.

High cycle fatigue performance at 650 ℃ and corresponding fracture behaviors of GH4169 joint produced by linear friction welding

GH4169 joints manufactured by Linear Friction Welding (LFW) are subjected to tensile test and stair-case method to evaluate the High Cycle Fatigue (HCF) performance at 650 ℃. The yield and ultimate tensile strengths are 582 MPa and 820 MPa, respectively. The HCF strength of joint reaches 400 MPa, which is slightly lower than that of Base Metal (BM), indicating reliable quality of this type of joint. The microstructure observation results show that all cracks initiate at the inside of specimens and transfer into deeper region with decrease of external stress, and the crack initiation site is related with microhardness of matrix. The Electron Backscattered Diffraction (EBSD) results of the observed regions with different distances to fracture show that plastic deformation plays a key role in HCF, and the Schmid factor of most grains near fracture exceeds 0.4. In addition, the generation of twins plays a vital role in strain concentration release and coordinating plastic deformation among grains.

Influence of intermetallic phase (TiFe) on the microstructural evolution and mechanical properties of as-cast and quenched Ti–Mo–Fe alloys

This study presents the phase analysis, microstructural characteristics, and mechanical property evaluation of the as-cast and quenched Ti–15Mo–xFe alloys with high iron content ranging from 4 to 12 weight percent. All the four alloys were produced in a vacuum-arc melting furnace. Heat treatment in the form of solution treatment was performed in a muffle furnace at a temperature of 1100 °C, with 1-h holding time and the samples were rapidly quenched in ice-brine. X-ray diffractometer (XRD) was used to analyses the phases present in each alloy whereas the optical microscope (OM) was employed to track the microstructural evolution and percentage porosity. The mechanical properties of the alloys were evaluated using a tensile test and compression test method while the micro-Vickers hardness measurements were conducted to evaluate hardness of the alloys. The XRD patterns of as-cast showed peaks belonging to the β and α″ phases and intermetallic B2 TiFe phases. The as quenched XRD peaks illustrated β phase only and Fe·Ti·O2 phases. The as-cast OM micrographs revealed equiaxed β grains, substructures, dendritic structure, and pores forming around the grain boundaries. The quenched OM showed only β equiaxed grains with pores throughout the grain boundaries. The tensile properties such as ultimate tensile strength (UTS) and elastic modulus (E) of as-cast TMF0 were 264 MPa and 79 GPa respectively and these properties changed upon quenching to 411 MPa and 66 GPa respectively. The elastic modulus of TMF1 in as-cast condition was 74 GPa. The UTS and E of TMF1, TMF2, and TMF3 in as-cast and quenched conditions were not recorded due to the fragility of the samples that failed prior to yielding any useful data. The compressive strength in as-cast and in quenched condition decreased with an increase in Fe content. The micro-Vickers hardness in as-cast and quenched conditions showed a similar trend with hardness increasing slightly upon quenching for TMF0, TMF1, and TMF3 alloys but slightly decreased in the case of TMF2. The fracture surfaces of all the as-cast and quenched alloys were comprised of ductile and brittle fracture.

Characterization of multidirectional carbon-nanotube-yarn/bismaleimide laminates under tensile loading

Unidirectional, cross-ply, and quasi-isotropic composite laminates are made from continuous carbon nanotube (CNT) yarns with bismaleimide (BMI) resin. The laminates are highly graphitic and have low resin content. Elastic modulus and strength of CNT/BMI laminates and IM7/8552 carbon-epoxy laminates are measured using a scaled-down tensile test method. For CNT/BMI laminates, the variation in the measured tensile modulus is high and the laminates fail in a more gradual manner than IM7/8552 laminates. Microscopy of the failed specimens indicates that intra-yarn splitting is a common feature in all CNT/BMI laminates tested. The results of this investigation will inform the development of CNT yarn reinforced composites for structural applications.

Verification Test and Research on Fitting Curve of Shear and Tensile Synthesis Method

Based on the recommended curve of concrete compressive strength tested by shear and tensile composite method, this paper combined with concrete specimens of different strength grades, ages and batches produced by several test verification units, adopted the in vitro shear and tensile test method introduced by the regulations, and used basically the same test equipment to collect the single shear and tensile strength and the compressive strength of cube specimens under the same conditions. Each batch was divided into 15 or 30 specimens. Through the collected test data, the conversion strength of the single shear, pull-out and shear tensile composite methods were calculated respectively. The relative error of a single specimen was calculated based on the average strength of each batch of concrete. The error distribution types and errors of each company were systematically studied, and finally the relative error data of each company were summarized, and the probability distribution parameters of the error of the Shear and tensile synthesis method were understood through probability distribution analysis, and the relationship between the error of the shear and tensile synthesis method, the single shear method and the pull method, and the influence degree on the conversion strength of the shear and tensile synthesis method were shown by using three-dimensional coordinates. Using the test data of &amp;quot;shear and tensile synthesis method&amp;quot;, &amp;quot;single shear method&amp;quot; and &amp;quot;pull-out method&amp;quot;, the scatter plot is drawn, and the error size is compared to explore the direction of further improving the detection accuracy of &amp;quot;shear and tensile synthesis method&amp;quot;.

Analisa sifat mekanik material logam melalui pemodelan dan simulasi uji tarik berdasarkan metode elemen hingga

Mechanical properties of material are attributes that should be known by engineers and product designers to determine the suitability of the structure being designed. One of the ways to determine the mechanical properties of a material is generally conducted by well-known tensile test. By the test, it will inform the elastic, plastic and fracture areas are known in the strain-stress diagram. Apart from that, the yield strength and maximum tensile strength can also be observed. The obstacle factor in experimentally tensile testing is the expensive costs, both for renting and procuring a tensile testing machine, which is called universal testing machine (UTM). This research aims to provide an alternative tensile test method, namely modeling and simulation techniques based on the finite element method (FEM). The workpiece material applied was ST37 Steel. This material is widely utilized in various types of industry, including the automotive, railway, and construction industries. The results show that the simulation can display all events that tensile tests may not be able to display experimentally, such as information on stress distribution and also elongation during the test. In addition, the mechanical properties of the ST37 material were obtained, including the yield strength of the material (yield point, Y) and the maximum tensile strength (ultimate tensile strength, σmax) which were 812.3 and 928.1 MPa, respectively.

FAIR and Structured Data: A Domain Ontology Aligned with Standard‐Compliant Tensile Testing

The digitalization of materials science and engineering (MSE) is currently leading to remarkable advancements in materials research, design, and optimization, fueled by computer‐driven simulations, artificial intelligence, and machine learning. While these developments promise to accelerate materials innovation, challenges in quality assurance, data interoperability, and data management have to be addressed. In response, the adoption of semantic web technologies has emerged as a powerful solution in MSE. Ontologies provide structured and machine‐actionable knowledge representations that enable data integration, harmonization, and improved research collaboration. This study focuses on the tensile test ontology (TTO), which semantically represents the mechanical tensile test method and is developed within the project Plattform MaterialDigital (PMD) in connection with the PMD Core Ontology. Based on ISO 6892‐1, the test standard‐compliant TTO offers a structured vocabulary for tensile test data, ensuring data interoperability, transparency, and reproducibility. By categorizing measurement data and metadata, it facilitates comprehensive data analysis, interpretation, and systematic search in databases. The path from developing an ontology in accordance with an associated test standard, converting selected tensile test data into the interoperable resource description framework format, up to connecting the ontology and data is presented. Such a semantic connection using a data mapping procedure leads to an enhanced ability of querying. The TTO provides a valuable resource for materials researchers and engineers, promoting data and metadata standardization and sharing. Its usage ensures the generation of finable, accessible, interoperable, and reusable data while maintaining both human and machine actionability.

Development of a laser‐assisted fused deposition modeling process for improvement in bond tensile strength of ABS

AbstractFused deposition modeling (FDM), an advanced 3D printing method, is a rapidly growing technology for realizing geometrically complex parts. FDM utilizes a thermoplastic feedstock that is heated and extruded through a nozzle to build up layers of material following toolpaths prescribed by three‐dimensional (3D) data. However, the rapid thermal cycles that the material undergoes during this process limit the formation, growth, and entanglement of the molecular chains in the material. Herein, we have proposed a novel laser‐assisted fused deposition modeling (LAFDM) process for the improvement in printed part properties such as bond width and tensile strength. The LAFDM system was developed consisting of an infrared laser, coupled with an industrial FDM printer. Using an adapted tensile testing method, the bond strength between deposited layers of acrylonitrile butadiene styrene (ABS) in 3D‐printed structures was assessed. Thermogravimetric analysis was used to monitor the thermal stability of the polymer to detect alterations to the chemical composition of the material as a result of the processing conditions. A 9.5% increase in the average bond tensile strength for the LAFDM‐printed specimen was observed compared to that of the non‐laser‐assisted FDM‐printed specimen. The improvement to the bond strengths was achieved without compromising the thermal stability of the polymer.

First-principles investigation of the Mg, Cu segregation at Al Σ5 (310) and Σ9 (221) symmetrical tilt grain boundaries

The segregation of alien solute atoms at grain boundaries (GBs) in nanocrystalline materials can dramatically affect their macroscopic properties. As important solutes in Al alloys, Mg and Cu atoms have been experimentally observed to segregate at GBs, which would render a significant impact on the material. In this work, first-principles calculations were used to conduct a systematic and comprehensive investigation to reveal the segregation behavior of Mg and Cu atoms at Al Σ5 (310) and Σ9 (221) GBs and its effect on GB properties. The negative segregation energy demonstrates that both Mg and Cu have a strong tendency to segregate to the Al GBs. Moreover, the segregation of Mg and Cu atoms can reduce the GB energy, indicating an increased thermodynamic stability of the GBs. Mechanical properties are explored by a combination of canonical Griffith fracture model with ab-initio tensile test method. Results reveal that the doped Mg will embrittle both GBs due to the elongation of interatomic bonds and depletion of charge density across the GBs. Contrarily, the segregated Cu contributes greatly to enhancing the GB strength by creating strong Cu-Al bonds with surrounding Al at GBs. Besides, the increased tensile separation displacement of GBs with Cu segregation also suggests an improved resistance to fracture, especially the Σ9 (221) GB. This work provides a theoretical understanding for the changes in microscopic properties of Al GBs caused by Mg and Cu segregation from an atomic and electronic level.

Numerical and experimental assessment of liquid metal embrittlement in externally loaded spot welds

Zinc-based surface coatings are widely applied with high-strength steels in automotive industry. Some of these base materials show an increased brittle cracking risk during loading. It is necessary to examine electrogalvanized and uncoated samples of a high strength steel susceptible to liquid metal embrittlement during spot welding with applied external load. Therefore, a newly developed tensile test method with a simultaneously applied spot weld is conducted. A fully coupled 3D electrical, thermal, metallurgical and mechanical finite element model depicting the resistant spot welding process combined with the tensile test conducted is mandatory to correct geometric influences of the sample geometry and provides insights into the sample’s time dependent local loading. With increasing external loads, the morphology of the brittle cracks formed is affected more than the crack depth. The validated finite element model applies newly developed damage indicators to predict and explain the liquid metal embrittlement cracking onset and development as well as even ductile failure.

Reducing stress concentrations in static and fatigue tensile tests on unidirectional composite materials: A review

The longitudinal tensile strength is an important basic property of unidirectional (UD) composites or plies that often governs failure in multidirectional laminates. The standard tensile testing methods almost always result in sample failure near the grip. Finite element analyses revealed the presence of multiaxial stress concentrations, including longitudinal, transverse, and shear stresses in the tabbed section of the standards’ recommended design. There are still unknowns and uncertainties about the causes of these stress concentrations and ways to eliminate them. A major challenge is obtaining acceptable failure within the gauge section and yielding the highest tensile strength of UD composites. This paper reviews the different methods for performing quasi-static and fatigue tensile tests on UD composites. The primary sources of stress concentrations and the parameters that affect them are reviewed using the available experimental and modeling investigations. We survey the effects of the different specimen and end tab designs as well as test setups on quasi-static and fatigue loading. Specific proposals are made for each of the discussed parameters for more reliable results.