Mechanical Testing Equipment Research Articles

Experimental investigation on mechanical property analysis of long and short fiber glass

Experts and different companies are always attempting to use composites in place of traditional materials to build designs that are more robust, lighter, more corrosion resistant, and other necessary qualities. Composites are being utilised in a growing number of products and applications. Increasing enterprise performance requirements, such as aerospace, automobiles, and other frameworks, require broader mechanical and hands-on testing. Mechanical test equipment has been developed using many of the equipment created to provide different ways to test composites based on the properties of the material and its expected end use. This article details various strategies for testing composites of composition (0.6 wt.% cobalt and fiberglass) for application to excavator engine hoods. Long glass fiber tensile and flexural strength were available at 97.22N/mm2 and 120.28N/mm2, respectively, while tensile and flexural strength of the reinforced short fiber was combined found in 94.12 N/mm2 and 110.23N/mm2. Also, the energy absorbed by long fiber is (7.21 Kgm) which is more than the short fiber i.e. (5 Kgm). Additionally, this article offers a source of information on these test methods that enable composites to be assessed at a high degree in order to obtain satisfactory results in terms of tension and impact.

Effect of Defatted Rice Bran Content on Physicochemical and Sensory Properties of Edible Cutlery Made from Rice Flour Green Composites using Compression Molding

The optical properties, moisture content, water activity, water absorption, mechanical properties, morphological observations, and sensory properties of edible spoons made from rice flour and rice flour green composites were investigated. The rice flour green composites were prepared with different weight ratios of rice flour and defatted rice bran as 100:0, 75:25, 50:50, and 25:75 by compression molding at 150°C at a fixed pressure of 9 bar for 7 min. Increasing the weight proportion of defatted rice bran in rice flour green composites resulted in higher lightness values, yellowness values, and water absorption, but redness values and moisture content decreased. Weight proportions of defatted rice bran in rice flour green composites up to 50 improved mechanical properties (both Izod impact and flexural strength). The cross-sectional surface after flexural testing of rice flour spoons was smooth, whereas rice flour green composite spoons were rough. Sensory properties of rice flour green composite spoons showed reduced appearance scores, color scores, texture scores, and overall preference scores but odor scores increased compared with rice flour spoons. Maximum compression force of rice flour green composite spoons increased with increasing weight proportion of defatted rice bran. An increase in maximum compression force measured by the mechanical testing equipment was related to a decrease in texture scores. Spoons made from rice flour and rice flour green composites showed promise as single-use edible cutlery and packaging.

Design and implementation of mechanical property testing equipment for thoracic aortic stent grafts

The mechanical properties of the stent graft are important factors influencing the outcome of TEVAR treatment and the occurrence of postoperative complications. The aim of this study is to improve and design a mechanical performance testing equipment for thoracic aortic stent grafts. The mechanical performance testing equipment consists of a radial force testing equipment of the stent graft designed by the wire compression grip method and a dynamic straightening force testing device with stable and controllable test conditions and continuously variable test angles. By constructing the testing equipment to physically measure the stent specimen, the experimental results reflect the trend of change and the simulation results are basically consistent, i.e. the mechanical properties of the thoracic aortic stent designed in this study is feasible and the measured data are valid. The testing equipment can provide the basis and reference direction for the quality testing of stent graft products, optimisation of mechanical properties of stent grafts and R&D innovation.

Mechanical Vibration Test Equipment Design Laboratory Capacity for Automotive Industry

Mechanical Vibration Test Equipment Design Laboratory Capacity for Automotive Industry

Thermal Shock Behavior of Si3N4/BN Fibrous Monolithic Ceramics.

To develop materials suitable for aerospace applications, silicon nitride/boron nitride (Si3N4/BN) fibrous monolithic ceramics with varying BN contents were prepared. Employing analytical techniques such as XRD and SEM, coupled with mechanical testing equipment, the influence of BN concentration on the thermal shock resistance of Si3N4/BN fibrous monolithic ceramics was assessed. When the thermal shock differential is less than 800 °C, its residual flexural strength gradually decreases as the thermal shock differential increases. Conversely, when the differential exceeds 1000 °C, the residual flexural strength of the material increases. The residual strength of all samples reached its peak after undergoing a thermal shock assessment at a 1500 °C differential. When the BN mass fraction is 5 wt.%, the residual strength after a thermal shock at a temperature difference of 1500 °C is 387 ± 19 MPa, which is 124% higher than the original strength of the sample that did not undergo thermal shock (25 °C, 311 ± 18 MPa). The oxide layer formed on the thermal shock surface played a role in bridging defects introduced during material surface processing.

Studying the STA effects on aluminium alloy joints by friction welding

This article examines the properties of joints fabricated by friction welding (FW) using AA6061-T6 and AA7075 as examples of both similar and dissimilar metals. It also looks at how heat treatment after welding affects the metallurgical characteristics of the joint. The heat treatment method under investigation combines solutionizing heat treatment with synthetic ageing (STA). The tensile characteristics, microhardness, and microstructure of the as-welded and STA-treated welded specimens are assessed in the paper using mechanical testing equipment and metallurgical characterization methods. The findings demonstrate that the joint characteristics are enhanced by precipitate nucleation occurring in the joint interface of the FW similar and dissimilar joint under STA treatment. On the other hand, the STA influence on the tensile strength (TS) of joints made with AA7075 was greater than that of similar joints made with AA6061-T6, as well as dissimilar joints made with both AA6061-T6 and AA7075. Additionally, after STA treatment, the similar joints showed a uniform distribution of hardness. However, in the dissimilar joint after STA treatment, the hardness dropped suddenly on the AA6061-T6 side, specifically from the partially deformed zone (PDZ) towards the heat affected zone (HAZ).

Modification to a testing assembly to enable strain-life measurements in pressurized hydrogen gas

Strain-controlled fully reversed fatigue testing, or strain-life testing, provides critical information on material lifetime and damage response. Strain-life data in hydrogen gas environments is missing in the literature and could provide valuable insights into hydrogen effects on the mechanical response of metals such as steel. We adapted existing hydrogen-gas-environment mechanical-testing equipment, which had been designed only for tensile loads, to accommodate the large compressive loads needed to perform strain-life testing. The considerations of these adaptations are discussed. Successful strain-life testing data were acquired from a 4130 pressure vessel steel.

Direct measurement and calculation of rubber bulk modulus by piston-cylinder method using conventional mechanical testing equipment

This article describes a method to directly measure the bulk modulus of rubber using a piston-cylinder type apparatus. The function of the testing apparatus is to reliably transfer load to the water inside the vessel and allow for the accurate and continuous measurement of volumetric displacement as the contents are compressed. During the test, load is applied to a piston-cylinder containing the rubber test sample and water using a conventional mechanical testing load frame. Load and the travel of the piston are recorded by a load cell and extensometer, respectfully. A brass or stainless steel plug of the same dimensions as the test sample is tested as a control sample to isolate the compliance of the system, including the compressibility of water and compliance of the o-rings which seal the piston-cylinder system. The results from this control test are used to decouple the compliance of the system from the sample test results. Load-linear displacement data are mathematically converted to pressure-volumetric displacement data, from which bulk modulus is calculated. The test apparatus and method are validated using the known bulk modulus of water. Finally, the bulk moduli for two similar rubbers are evaluated. The validity of the results and limitations of the device are discussed.

Adaptation of a Standard Industrial Peel Test for Testing Consolidants in the Conservation Studio

ABSTRACT Adhesives and consolidant strength play a major role in many conservation treatments. In industry, adhesive strength is often determined using standardized tests including 90° peel tests. However, not all conservation studios have or can afford mechanical testing equipment for such tests, although it is often readily accessible at third-party facilities. For a university conservation project, an international standard 90° peel test was modified to study the adhesive strength of consolidants for zinc white paints. Consolidants were applied to painting canvas strips, which were then adhered to zinc white paint layers on glass supports. The strips were peeled downward by continually adding fine sand to a cup attached to the end of the canvas strips. Video recordings were made of the continual loading and sudden stepwise extensions of the peeling samples, so that step-wise force - peel length curves could be plotted for each specimen. The data combined with examination of the peeled surfaces provided important qualitative information over strength and toughness (ductility/brittleness) for comparing the tested consolidant-zinc white systems. The adapted peel test is therefore a valuable method for testing adhesives and consolidants in the conservation studio. However, one must avoid overinterpreting the results, since consolidant selection depends on more factors than just mechanical properties.

Chemical Surface Modification Methods of Resin Composite Repaired with Resin-Modified Glass-Ionomer Cement.

This study examined the chemical surface modification methods of resin composite repaired with resin-modified glass-ionomer cement (RMGIC). Ninety aged resin composite rods were produced and sorted into 9 groups of 10 specimens and surface modified with silane agent and/or bonding agent as follows: group 1, no surface modified; group 2, etch + single bond 2 (SB2); group 3, SB2; group 4, etch + RelyX ceramic primer (RXP) + SB2; group 5, RXP + SB2; group 6, etch + single bond universal (SU); group 7, SU; group 8, etch + RXP + SU; and group 9, RXP + SU. A clear silicone mold was placed on the top of specimen center, and then filled with RMGIC. The specimens' shear bond strengths (SBSs) were examined in mechanical testing equipment. To determine failure types, the fractured specimen surfaces were inspected using a stereomicroscope. The data collected were analyzed using one-way analysis of variance, and significance level was operated using Tukey's test (p < 0.05). Group 8 had the greatest SBS, but it was statistically indistinguishable from groups 4, 5, and 9. The most frequent fracture mode was adhesive failure. High SBS was commonly associated with mixed failure. The use of bonding agents enhances the resin composite's wettability and allows it to bond to RMGIC. Moreover, the use of the silane coupling agent before applying bonding agent showed significantly higher bonding ability of resin composite and RMGIC interface.

Study on the effects of laser quenching power and scanning speed on the property of cast iron

The laser surface quenching power, scanning speed, and spot area have significant effect on the properties of the laser quenched materials. The effects of laser quenching power and scanning speed on the tribological, vibration, and noise performance of gray cast iron (HT250) are studied in this paper. Keeping the laser quenching spot constant, 12 cast iron discs are laser quenched by changing the laser quenching power and scanning speed. Various mechanical, tribological, and dynamical testing equipment are used to characterize the properties of the laser quenched cast iron discs, in terms of the surface hardness, residual stress, friction coefficient, and frictional vibrations and noise of the cast iron discs. The experimental results show that after laser surface quenching, the surface hardness of the cast iron disc has been increased more than 4 times, the residual stress on the disc surface is changed from tensile stress to compressive stress, the friction coefficients of the laser quenched cast iron discs have been significantly increased, and the vibration and noise generated from the laser quenched cast iron discs have been significantly changed. This research has significance to the improvement of the surface performance of automotive brake discs and the control of braking frictional vibrations and noise.

Plasmonic Strain Sensors Based on Au-TiO2 Thin Films on Flexible Substrates.

This study aimed at introducing thin films exhibiting the localized surface plasmon resonance (LSPR) phenomenon with a reversible optical response to repeated uniaxial strain. The sensing platform was prepared by growing gold (Au) nanoparticles throughout a titanium dioxide dielectric matrix. The thin films were deposited on transparent polymeric substrates, using reactive magnetron sputtering, followed by a low temperature thermal treatment to grow the nanoparticles. The microstructural characterization of the thin films’ surface revealed Au nanoparticle with an average size of 15.9 nm, an aspect ratio of 1.29 and an average nearest neighbor nanoparticle at 16.3 nm distance. The plasmonic response of the flexible nanoplasmonic transducers was characterized with custom-made mechanical testing equipment using simultaneous optical transmittance measurements. The higher sensitivity that was obtained at a maximum strain of 6.7%, reached the values of 420 nm/ε and 110 pp/ε when measured at the wavelength or transmittance coordinates of the transmittance-LSPR band minimum, respectively. The higher transmittance gauge factor of 4.5 was obtained for a strain of 10.1%. Optical modelling, using discrete dipole approximation, seems to correlate the optical response of the strained thin film sensor to a reduction in the refractive index of the matrix surrounding the gold nanoparticles when uniaxial strain is applied.

25 - Analysis of Indirect Restorative Materials Submitted to Different Conditioning Protocols

The aim of this study was to evaluate the influence of hydrofluoric acid application time and concentration on bond strength and surface morphology of three indirect restorative materials. Samples measuring 4x4x0.8 mm were obtained from three materials (lithium monosilicate reinforced by zirconia - Celtra Duo, nanoceramic resin - Lava Ultimate and hybrid ceramic - Vita Enamic). These materials were conditioned with hydrofluoric acid at concentrations of 5% or 10% for 20, 40, 60 or 90 seconds. In addition, a control group was adopted, in which no conditioning was performed, totaling 9 groups for each material. The analysis of bond strength was performed using the microshear test (n=6). For this purpose, cylinders of Variolink Esthetic LC resin cement were made on the conditioned samples, using a silicone matrix. The test was performed in a mechanical testing equipment, in which the samples were fixed and with the aid of an orthodontic wire, tension was applied to the cylinders. Bond strength data were submitted to two-way ANOVA and Tukey's test (α=0.05). The surface microstructure of each material was observed through images obtained by the technique of scanning electron microscopy (SEM) (n=2). Celtra Duo presented better bond strength values when subjected to etching with 10% hydrofluoric acid for 40, 60 and 90 seconds. For Lava Ultimate, better results were obtained with application of 10% acid concentration for 20 and 40 s, while Vita Enamic showed better results after application of 5% hydrofluoric acid for 40 and 90 seconds and at 10% for 20 and 40 s. Through the images obtained by the technique of scanning electron microscopy (SEM) it was possible to observe the appearance of irregularities on the surface of each material evaluated after conditioning. The evaluated restorative materials showed different behaviors after conditioning protocols with hydrofluoric acid, therefore, the professional must adopt the best hydrofluoric acid concentration and time protocol for each specific material in order to obtain a satisfactory and effective adhesive procedures.

A Method for Characterising the Influence of Casting Parameters on the Metallurgical Bonding of Copper and Steel Bimetals.

Traditional casting technology offers two mayor drawbacks towards research activities. On the one hand, time and resources needed for every casting are rather high. The mould has to be able to withstand the high temperatures introduced by the melt and provide cooling for the cast part. Preparation and installation of measuring equipment therefore takes time. Additionally, due to the high mass of the mould when compared to the cast part, parameter variations are rather limited in their resulting effect on the temperature-time profile being one of the most prominent factors regarding cast quality. Especially when pouring by hand, variations in casting times and rates superimpose effects created intentionally. Therefore, a different process was advanced and evaluated, allowing to minimise some of the drawbacks mentioned before. The key idea is to drastically reduce casting size to the dimensions of one specimen and to apply a highly automated production route. As such, a mirror furnace was modified as to allow the processing of melt. Due to the specimens size, an adaption of mechanical testing equipment was performed and evaluated. As an example, copper-iron bimetal specimens were examined by light microscopy, micro hardness testing, nanoindentation as well as tensile and torsion testing. As the results were consistent, the newly introduced method can be applied successfully in casting research. This allows for highly reproducible results, reducing the uncertainty of temperature measurements of a specimen due to the distance between them. The possibility of separating influencing variables like maximum temperature and cooling rate allows an analysis of the casting process, which would require different moulds to do so in traditional casting methods. The next steps will be directed at a broader variety of metals processed and at a direct comparison between the new process route and traditional casting technology.

Teaching Material Testing and Characterization with an Open, Accessible, and Affordable Mechanical Test Device

Hands-on experiences in biomechanics and biomaterials courses are an important part of biomedical engineering education. Curricula of those courses often include laboratory modules on material testing and characterization. Unfortunately, large and expensive mechanical testing equipment may not be available to all students, thus limiting students’ access to actual hands-on experience. Here, we introduce an open, accessible, and affordable mechanical test device that ensures that every student gets their hands on test equipment and a test specimen. In fact, the device has a small form factor, is inexpensive, and can therefore be taken home. The device is built with low-cost components and 3D-printed parts for a total cost of less than $45. The device also makes use of each student’s cell phone camera for optical strain measurements, thereby avoiding the need for expensive imaging equipment. In addition to the device, we also introduce a rich set of supplementary materials that make adoption and application by educators and students as easy as possible. A first experience in a 20-student biomedical engineering technical elective class has demonstrated ease of use and anecdotally confirms the device and material’s usefulness in practical teaching. However, more formal evaluation is needed to demonstrate that our test device and materials enhance laboratory teaching.

Preparation and Mounting of Whole Blood Clot Samples for Mechanical Testing.

Studying and quantifying the mechanics of blood clots is essential to better diagnosis and prognosis of, as well as therapy for, thromboembolic pathologies such as strokes, heart attacks, and pulmonary embolisms. Unfortunately, mechanically testing blood clots is complicated by their softness and fragility, thus making the use of classic mounting techniques, such as clamping, challenging. This is particularly true for mechanical testing under large deformation. Here, we describe protocols for creating in vitro blood clots and securely mounting these samples on mechanical test equipment. To this end, we line 3D-printed molds with a hook-and-loop fabric that, after coagulation, provides a secure interface between the sample and device mount. In summary, our molding and mounting protocols are ideal for performing large-deformation mechanical testing, with samples that can withstand substantial deformation without delaminating from the apparatus. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Cube-shaped blood clot preparation Basic Protocol 2: Sheet-shaped blood clot preparation.

Assessment of Force Retention between Milled Metallic and Ceramic Telescopic Crowns with Different Taper Angles Used for Oral Rehabilitation.

The present study assessed the retention forces corresponding to different telescopic systems used in removable prosthetic dentures. The telescopic systems were represented by Co–Cr alloy or zirconia-based primary crowns and Co–Cr secondary crowns. All crowns were manufactured using computer-aided design/computer-aided manufacturing technology (CAD/CAM). Two types of reference abutment teeth (upper canine and first upper molar) were selected in order to obtain the telescopic crowns and two taper angles—of 0° and 2°—were used for the design of the crowns. A number of 120 samples of telescopic crowns were obtained and subjected to mechanical tests, following a specific protocol, on a mechanical testing equipment. The retention of the telescopic systems was evaluated for different sets of cycles (up to 360), represented by movements that simulate the intraoral insertion and disinsertion of the telescopic systems. The present study highlights that the telescopic systems in which the primary crown is made of zirconia ceramics presents more advantages than those made of Co–Cr. All telescopic systems studied, highlighted that by modifying the taper angle from 0° to 2°, the retention forces have decreased, irrespective of the materials used for the fabrication of the primary crown, suggesting that by using a taper angle of 0°, which is known to be ideal, more efficient, and reliable prosthesis can be developed. Thus, even though the ceramic–metallic telescopic system exhibited the highest retention, all telescopic crowns evaluated registered values between 2–7 N, indicating that they are suitable for clinical use.

Operational temperatures of all-weather thoroughbred racetracks influence surface functional properties

The surface temperature of all-weather racetracks has previously been correlated to speed. However specific functional properties such as grip, cushioning and impact firmness have not been directly compared to environmental conditions. The objective of this study was to assess how temperature influences functional properties of racetracks, and categorise surface wax binders according to first thermal transition peak, and compare responses at different operational temperatures. Functional properties were determined for UK all-weather racetrack surfaces (n = 6) using mechanical testing equipment which assess the loads experienced by the forelimb at gallop (randomised block design). Tests were carried out using latex lined moulds, embedded within a test box with a predefined boundary at 0 °C, 20 °C and 40 °C. Wax binders underwent differential scanning calorimetry to identify thermal transition peaks. Changes in operational temperatures significantly influenced surface responses when a wax binder was part of the composition. Temperature was a factor that significantly contributed to the variation found in horizontal grip ( F 2, 237 = 65.69, P < 0.001), cushioning ( F 2, 237 = 58.24, P < 0.001), impact firmness ( F 2, 237 = 28.02, P < 0.001) and rotational grip ( F 1 2, 65 = 9.45, P < 0.001). Using a test box meant individual racetracks were generalised but this enabled conditions to be controlled. Colder temperatures demonstrated higher surface hardness and shear resistance that may increase risk of musculoskeletal injury although this was not measured here. Awareness of the effect temperature has on specific track behaviour allows maintenance protocols to be further developed to improve consistency when temperatures change, with the aim of improving safety. • Functional properties of UK racetracks alter during normal operational temperatures. • Greater variation in track cushioning and hardness was seen at lower temperatures. • Repeated drops akin to used-tracks produced higher hardness at lower temperatures. • Individual first thermal transition peak influences track response to temperature. • A first thermal transition peak <40 °C showed greater range of hardness and grip.

Residual stress–driven test technique for freestanding ultrathin films: Elastic behavior and residual strain

Abstract

Direct determination of the interlayer van der Waals bonding force in 2D indium selenide semiconductor crystal

The interlayer van der Waals bonding force in crystalline InSe was directly measured using a mechanical test equipment. The bulk γ-InSe crystal was grown by the temperature difference method under controlled vapor pressure, a unique liquid phase solution crystal growth method with a low and fixed growth temperature. The measured bonding force in the crystal was 20.8 N/cm2, which is greater than that in 2D crystalline GaSe. We also made theoretical discussion of the van der Waals forces in InSe, based on the fluctuations in the electron cloud distributions around the atoms.