Material Mechanical Testing Research Articles

Experimental study on the mechanical properties of the reinforced transparent building membrane material STFE

STFE is a new type of reinforced polymer building membrane material that combines excellent mechanical properties and transparency by using high-strength fibre mesh, which eliminates the limitations of poor transparency in coated fabric membranes and low strength in polymer membranes. In this study, in order to investigate its strength indicators and mechanical properties, material mechanical tests such as uniaxial, biaxial, and picture frame tests were conducted, obtaining the basic mechanical parameters of the material, including warp and weft direction tensile strength, tear strength, welding seam strength, elastic modulus and Poisson's ratio, shear modulus, and creep elongation rate, among others. Additionally, linear and nonlinear stress–strain mechanical models for uniaxial and biaxial loading were proposed for this material, as well as time-dependent creep and stress relaxation models. These mechanical models were validated and found suitable for numerical simulations of the material. The research results lay the preliminary foundation for the application of this material in large-span tensile transparent membrane structures.

Preparation and Performance of Multilayer Si-B-C-N/Diamond-like Carbon Gradient Films

Si-B-C-N/diamond-like carbon (DLC) gradient films with different layers were prepared on a glass substrate by radio frequency magnetron sputtering, and the structure and surface morphology of the resulting films were analyzed by scanning electron microscopy, Raman spectrometry, and X-ray photoelectron spectroscopy. The mechanical and optical properties of the films were studied using a multifunctional material mechanical testing system, UV-Vis spectrophotometer, and micro-Vickers hardness tester. The gradient structure promotes the formation of sp3 bonds and improves the hardness and optical transmittance of the resulting films. Among the prepared films, the single-layer Si-B-C-N/DLC gradient film shows the highest optical transmittance (97%). Film-substrate adherence is strengthened by the introduction of the gradient structure. The best adhesion was obtained with a double-layer Si-B-C-N/DLC gradient film. Suitable anti-wear properties were exhibited in both dry (0.18) and wet (0.07) conditions. In this paper, evaluation of the microstructural, optical, and mechanical properties of the films could provide new insights into improvements in the bonding force of glass-based DLC films and enrich the experimental data of DLC multilayer film systems.

Quantifying alignment deviations for uniaxial material mechanical testing via automated machine learning

The loading coaxiality of uniaxial material mechanical testing (UMMT) introduces an additional bending stress, significantly affecting the admeasurement of material properties. Owing to the lack of a calculation method, only qualitative analysis of misalignment can be performed using the current technologies. To quantify the alignment deviations of the UMMT, the relationship between the strain measurement points on the specimen and alignment deviations were mapped using automated machine learning. A finite element model was used to obtain the dataset. The numerical results indicated that the established deep learning model can be utilized to quantify the alignment deviations for UMMT.

Machining performance of in-situ TiB<sub>2</sub> particle reinforced Al-based metal matrix composites: A literature review

The in-situ TiB₂ particle reinforced Al-based metal matrix composites have become a series of promising aeronautical materials due to the advanced properties such as finer evenly-distributed grains, cleaner particle-matrix interface, improved mechanical performance and strength when compared with ex-situ SiC particle reinforced Al-based metal matrix composites. However, over the last 50 years, a significant body of research has been carried out on ex-situ SiC particle reinforced Al-based metal matrix composites from material fabrication process, material property improvement, material mechanical test to machining performance such as machined surface integrity, cutting process simulation and modeling, parameter optimization and fatigue characteristics. For in-situ TiB₂ particle reinforced Al-based metal matrix composites, studies in recent years were mainly focused on the material preparation process and property development and few published works was found on the machining performance of this new kind material. Hence, this article aims to provide a general overview of recent achievement on machining performance of in-situ TiB₂ particle reinforced Al-based metal matrix composites.

Technology in Sports Biomechanics

Biomechanics is defined as the study of the structure and function of biological systems by the methods of mechanics. The range of applications and methodologies in biomechanics is varied, from gait analysis to manufacturing of implants, orthotics or prosthetics devices, rehabilitation technology, fluid dynamics analysis in biological systems, and tissue and cellular biomechanics. An underlying understanding of fundamental applied mechanics principles is required to understand the stresses and strains the body components cause, or are subject to, under different activities. However, it is also necessary to know which biological components are put in place to absorb shock and protect the living systems. Motion-capture technology, material mechanical testing, medical imaging, computer-aided design, and computational fluid dynamics are some of the methodologies required to work in the field. All of these areas come together when biomechanics applications are used in the analysis of sports performance.

Research on multidimensional loading device of material mechanical test

A multidimensional loading device for the material mechanical test based on Stewart Platform was proposed and manufactured in this paper. A determination method of mechanism parameters toward specific engineering requirements was analysed via inverse kinematics and contact interference boundary condition of mechanism components. A set of optimized mechanism parameters was achieved and then the pose space was obtained. Meanwhile, five repeated quasi-static standard tensile tests were performed on the multidimensional loading device and the standard tensile testing machine, respectively. The average yield strength and ultimate strength of the specimen achieved from the different testers were both merely 1.13%. Results indicated that material mechanical multidimensional loading could be conducted by the parallel mechanism.

Mechanical characterization of raw material quality and its implication for Early Upper Palaeolithic Moravia

Abstract Raw material mechanical tests were conducted to answer the question whether differences in raw material procurement among Early Upper Palaeolithic populations in Moravia (Czech Republic) may have been driven by different mechanical properties of those materials. Characterization of mechanical properties of erratic flints and Krumlovský les I type chert show that the relatively finer-grained erratic flints, preferred by local Aurignacian populations, are more easily and probably also predictably knapped at higher speeds, such as reached with soft (antler, wood) percussors, whereas cherts of Krumlovský les I type, exploited by both Szeletian and Aurignacian populations, are more resistant to fracture propagation. This implies the suitability of the former material for fine blade and bladelet production, and of the latter to projectile (e.g. Szeletian leaf points) manufacture, and possibly explains the export of leaf points from Szeletian areas (the Krumlov Forest) to Bohunician and Aurignacian sites within Moravia. Exploitation of erratic flints was easier as regards Aurignacian, and probably entire Upper Palaeolithic knapping technology. Certain tasks, however, were better met with other raw materials, thus reflecting the relativity of chipped stone raw material quality perception in the Palaeolithic.

Rheological properties, morphology, mechanical properties, electrical resistivity and EMI SE of cyclic butylene terephthalate/graphite/carbon black composites

According to traits of cyclic butylene terephthalate (CBT) oligomer polymerizing into poly(butylene terephthalate) (PBT), the composites with high electromagnetic interference shielding effectiveness (EMI SE) were obtained based on CBT oligomer, graphite (GR) and carbon black (CB). The effects of GR and CB on rheological properties, morphology, mechanical properties, and electrical resistivity and EMI SE of PBT composites have been investigated using rheological rheometer, scanning electron microscope (SEM), material mechanical testing machine and electromagnetic shielding measuring instrument, respectively. The synergistic action of GR and CB was observed, which made PBT/GR/CB composites exhibit good mechanical properties, low electrical resistivity, and high vicat softening temperature (VST). Also, the incorporation of CB into PBT/GR composites improved largely EMI SE of composites, and the optimal EMI SE was determined to be ~ 60 dB over the frequency range of 30–3,000 MHz.

The Effect of Graphite on the Water Uptake, Mechanical Properties, Morphology, and EMI Shielding Effectiveness of HDPE/Bamboo flour composites

This goal of this work was to study the effect of graphite on the water uptake, mechanical properties, morphology, and electromagnetic interference shielding effectiveness (EMI SE) of HDPE/Bamboo flour composites using the material mechanical testing machine, scanning electron microscopy (SEM), and EMI shielding apparatus. The water uptake of the composites was improved by graphite. Compared with the neat HDPE/bamboo composites, the flexural strength of the graphite-filled composites showed a small decrease, but the flexural modulus was enhanced greatly, indicating that graphite could effectively elevate the stiffness of the composites. An obvious result was that the toughness of composites was improved considerably by the graphite. The notched impact strength of the composites was increased from 5.18 to 9.0 KJ/m2 as graphite content was increased from 0 to 40 %. A large amount of graphite would increase the conductivity property and the EMI SE. The HDPE/bamboo composite with 40% of graphite exhibited electrical resistivity of 31.2 .cm and the EMI SE of 20 dB in the frequency range of 30 - 3000 MHz.

An Inverse Method to Reconstruct Complete Stiffness Information of Rubber Bushing

A specific rubber bushing, with only radial and axial stiffness data having been acquired, is studied. In terms of the hyperelastic material of this bushing, three-term Ogden law is utilized as the material constitutive model which requires to be characterized. Without the material mechanical tests provided, a parameter identification method is proposed for searching a group of acceptable parameters which are able to model rubber-like material of this rubber bushing. In this case, based on the nonlinear finite element analysis method and optimization technique, the parameters of material law are determined, and the rotational stiffness of this bushing is also evaluated. The complete stiffness information has been established.

Discussion on Masonry Structure Model Mechanical Property Test

The problems in the mechanical test of masonry structure model were discussed in this paper, including the masonry material, similar relationship, shaking table test device, judgment of wall cracking and number of cycles in pseudo-static loading test. The conclusions are: (1) for the masonry material mechanical test, usually the size decreased the strength increased, but if the laying method and appropriate adjustments in the process of the test mixture ratio, the size effect can be greatly reduced; (2) In the dynamic test of the masonry structure, for the gravity distortion model, the common way is the external prestressing method, but in this method the tension force is not constant, which is differ from the actual situation; (3) The wall cracking can be judged when the main tension crack of the wall appeared; (4) The loading cycle in the pseudo-static test of masonry wall would be twice.

A method of thermal calculation of high-temperature units for material mechanical testing equipment

A method of thermal calculation of high-temperature units for material mechanical testing equipment