Test Methods For Mechanical Properties Research Articles

An innovative test method for mechanical properties of sandstone under instantaneous unloading confining pressure

An innovative test method for mechanical properties of sandstone under instantaneous unloading confining pressure

A novel test method for mechanical properties of characteristic zones of girth welds

The safety evaluation of girth welds is an important issue for steel pipes. Current standards and studies all regard the weld as a uniform material, ignoring its inhomogeneity. In this paper, a specimen processing method for weld characteristic zones is proposed. Based on the natural morphology of the weld structure, specimens are accurately designed and processed for each characteristic zone. In addition, a testing method to determine the tensile properties in the characteristic zones of the weld is also proposed, solving the absence of weld mechanical properties in existing steel pipe safety evaluations. This method was used to test an X80 automatic girth weld, and the results showed that the tensile properties significantly differed between different characteristic zones of the girth weld. The inhomogeneity displayed in this weld demonstrates how a more detailed assessment of weld properties should be considered in practical engineering and safety evaluations.

A Mini Review on Testing Methods for Mechanical Properties of Natural Fibre Honeycomb Sandwich Structure and Fractography Analysis

This paper is a review of the past research of mechanical testing methods for natural fibre honeycomb sandwich structure as well as failure modes analysis at a microscopic level by using Scanning Electron Microscope (SEM). As the world is garnering attention towards renewable resources for environmental purposes, studies of natural fibre have been increasing as well as the application of natural fibre throughout various industries such as aerospace, automobiles, and construction sectors. This paper is started with brief information regarding the honeycomb sandwich structure, introduction to natural fibre, its applications as well as the factors affecting the performances of the structure. Next, the mechanical testing methods are listed out as well as the expected outcomes obtained from the respective testing. The mechanical properties are also identified by conducting lab tests according to the ASTM standard for sandwich and core structures. The microstructure of the deformed samples is then examined under Scanning Electron Microscope (SEM) by using different magnifications to study the failure mechanisms of the samples. The images obtained from the SEM test are analyzed by using fractography which will show the failure modes of the samples. This article is based on past research conducted by professional on the related topic.

Study on mechanical properties testing of highway concrete pavement construction machinery materials

In order to solve the problems of large error and long time-consuming in the traditional mechanical property test methods, a new mechanical property test method for highway concrete pavement construction machinery materials is proposed. The relationship between the deformation component and the displacement component of the microstructure of the concrete pavement in the equilibrium coordinate system is obtained. The limit value of the critical thickness of the construction material of the highway concrete pavement is obtained by the second derivative function. Based on the analysis principle of AFM force curve, the relationship between mechanical materials and elastic modulus of highway concrete pavement construction is determined, and the performance analysis of highway concrete pavement construction mechanical materials is realised. The test results show that the error of mechanical properties analysis of highway concrete pavement construction machinery materials by the proposed method is only 0.3%, and the test time is short.

Ultra-high temperature mechanical property test of C/C composites by a digital image correlation method based on an active laser illumination and background radiation suppressing method with multi-step filtering.

Carbon/carbon (C/C) composites have been widely used in aerospace engineering because of their high temperature resistance. However, the commonly used non-contact deformation measurement method based on digital image correlation (DIC) still has some problems of speckle preparation and background radiation in an ultra-high temperature environment above 2000°C. An ultra-high temperature mechanical property test method based on active laser illumination and a background radiation suppressing method with multi-step filtering is proposed. In the proposed method, a laser with good coherence is used as the active illumination source to generate laser speckles that will not fall off or discolor as temperature increases. Also, a multi-step filtering device is devised with the combination of a spatial filter, plano-convex lens, polarizing filter, and two different bandpass filters, which can successfully suppress the background radiation and retain the characteristics of laser speckle patterns at the same time. Tensile tests of C/C composite had been carried out at ultra-high temperatures of 2200°C, 2400°C, 2600°C, and 2800°C. The experimental results showed that high-quality laser speckle images were obtained and the deviations between the elastic moduli obtained by the proposed method and by the high temperature contact extensometer were all less than 7%.

Effect of cattle manure ash’s particle size on compression strength of concrete

Cattle manure ash (CMA) is an industrial waste generated by biomass power plants. The objection of this study is to confirm how the particle size of cattle manure ash influence the compression strength of concrete. To obtain different particle size of cattle manure ash, we used a muffle furnace to simulate the biomass power combustion temperature (500 °C, 650 °C, and 800 °C). These CMAs were then analyzed via X-ray diffraction (XRD) and scanning electron microscopy (SEM). Compression strength of concrete is obtained by Standard for test methods for mechanical properties of ordinary concrete. Grey’s relevancy principle was used to determine the effect of CMA with particle sizes of 0–3, 32–65, 65–80 μm, and >80 μm on the compression strength of concrete. The results revealed that 15% CMA volume of cement replacement yielded a positive correlation between particles with sizes of 0–3 μm and >65 μm on the compression strength; a negative correlation was obtained for other particle sizes. The mechanism of improving the compression strength of CMA concrete include the particle improving density of the binary mixture, improving the chemical composition and structure between the aggregate and the gelled materials and improving the degree of the core effect. The results of this study can be used as a guide for extending the use of CMA in concrete.

Test method for mechanical properties of implantable catheters according to DIN 10555-3.

To enable causal analysis of port catheter failure, this study aimed to develop an experimental setup for uniaxial tensile tests that addresses the specific requirements of highly elastic medical catheters; and to quantify parameters of the catheters' mechanical competence with respect to effects of artificial aging. Segments of 6F-polyurethane catheters were tested in their native status, after chemical and after mechanical aging. Tension experiments were performed with a rate of 220 mm/min until catheter failure. Material behavior was analyzed based on load cell measurements of the universal test system and an additional optical distance registration. The Young's modulus, the ultimate stress and the ultimate strain were determined. Chemical aging significantly decreased Young's modulus (84%; p = 0.001) and ultimate stress (83%; p < 0.001), whereas mechanical aged samples demonstrated similar results for the Young's modulus (p = 0.772) and a non-significant rise of ultimate stress (13%; p = 0.128). Ultimate strain did not differ significantly regardless of the pretreatment. The results proof reliability, reproducibility and sensitivity to quantify artificial aging induced variations and also promise to detect deviations in material features caused by long-term clinical usage of catheters.

Standardized test methods for mechanical properties of dental prosthetic/restorative materials and their applications

,4) A number of mechanical test protocols have been developed to ev aluate the mechanical properties for dental prosthetic and conservative materials. This review article presents and discusses internationally standardized test methods including uniaxial and biaxial flexural test, compressive and diametral tensile tests, Weibull reliability test, fracture toughness tests, and their applications. There has been little information on the relationship between the results from standardized tests and clinical performance for dental materials. Thus, the mechanical properties resulting from standard tests can merely be used in evaluation of mechanical quality among various candidates. For more practical evaluation of mechanical performance of dental materials, there are needs for developing a quasi-clinical test protocol under considerations with stress concentration and distribution and clinical complexity. Furthermore, those results should be compared with the mechanical properties resulting from standardized tests.

プラスチックの材料試験方法

プラスチックの材料試験方法

Recycled Aggregate Performance Experiment Study on Basis of Saturated Surface Dried Crush Value Index

Crush value index is a key parameter for measurement of coarse aggregate strength performance. In this paper the eight group of crush value index are tested for the recycled aggregate used of waste concrete which is gathered from three different remove construction plants. The experiment analysis result is shown that the crush value of recycled aggregate is greater 2.5 times than natural aggregate. Meanwhile, compared with air dried condition, the crush value index of saturated face dried condition is from 7.22% to18.2%. Furthermore the recycled aggregate can be suitable to make concrete requirement which compression strength grade is C35 and lower than C35 in China. In the experiment, comparative analysis is found that the RA-10 aggregate compressive strength is slightly from 2.06% to 8.7%. Those which are higher limit value of standard for test method of mechanical properties on ordinary concrete and the divergence are less than 10%. Consequently the recycled aggregate can be used for concrete, and its compressive strength is also fundamentally satisfied for requirement of concrete compressive strength.

International round Robin test for mechanical properties of BSCCO-2223 superconductive tapes at room temperature

International RRT was carried out in order to establish the test method for mechanical properties of commercial BSCCO superconductive tapes under cooperation of seven research laboratories. From the stress versus strain curve, the following quantities were evaluated; modulus of elasticity, 0.2% proof strength, fracture strength and stresses at fixed strains. The scatter of measured values was analyzed by evaluating the relative standard uncertainty ( RSU), which is the standard uncertainty divided by the average. The expected value of RSU for N = 3 was derived for each mechanical quantities. In order to make clear the major contribution to the scatterings, the F test was applied. The major source of RSU’s was attributed mostly to the influence of inter-laboratory scattering.

Test Methods for Mechanical Properties of Structural Adhesives

One of the greatest drawbacks to predicting the behaviour of bonded joints has been the lack of reliable data on the mechanical properties of adhesives. In this study, methods for determining mechanical properties of structural adhesive were discussed. The Young’s modulus, Poisson’s ratio and tensile strength of the adhesive were tested by dogbone specimens (bulk form) and butt joint specimens (in situ form). The shear modulus and shear strength were test by V-notched specimens (bulk form) and thick adherend lap-shear (TALS) joint specimens (in situ form). The test results show that the elastic modulus provided by the manufacturer is too low, the dogbone specimen is better than the butt joint specimen to test the tensile strength and elastic modulus and the TALS joint specimen is better than the V-notched specimen to test the shear strength.

Mechanical Property of FRP Bar and Design Method of Hybrid FRP Bar

The paper described the detailed design and production method of the FRP bar and the anchorage device, and it also introduced the test method of mechanical properties on the tensile strength, elastic modulus and the rate of elongation of the FRP bar. Moreover, it conducted statistical analysis into test results and put forward the mechanical property index for structural design of the FRP bar concrete. Test results indicated that stress-strain relation of the FRP bar presented linear variation. FRP bar is superior to steel bar concerning high tensile strength-quality ratio and high durability, the elastic modulus and the rate of elongation of the FRP bar are also less than those of the steel bar, it is practicable to use FRP bar as a new type of tensile material in concrete structures. And then, it put forward design ideas of the hybrid FRP bar by a series of analysis on the hybrid effect and the ductility of the hybrid FRP bar.

Recommendation of RILEM TC 129-MHT 'Test methods for mechanical properties of concrete at high temperatures' Modulus of elasticity for service and accident conditions

Recommendation of RILEM TC 129-MHT 'Test methods for mechanical properties of concrete at high temperatures' Modulus of elasticity for service and accident conditions

Evaluation of Bending Rigidity of CFRP Skin-Foamed Core Sandwich Beams

Bending tests of a commercially available sandwich plate with CFRP-fabric skin and acrylic foam core were conducted primarily by means of a three-point bending. The effects of the span and the radius of the tip of the loading device on the bending modulus and strength were examined systematically. Test data on bending rigidity did not coincide with those calculated from a modified beam theory where the effect of the shearing rigidity of the core was incorporated, although the tendency that the bending modulus increased, the span was the same for both experiment and theory. Based on these results, this paper proposes a desirable data reduction scheme by which the correlation between theory and experiment could be made clear. The applicability of a so-called compression bending test was also demonstrated. This paper is the summary of the original work [Itohiya, G. (1999). Mechanical Property Test Method for CFRP/Hard Foam Core Sandwich Plates, MS Thesis, Science University of Tokyo, in Japanese].

The tensile property of commercial Bi2223 tapes: a report on the international round-robin test

In order to establish the test method of mechanical properties of oxide composite superconductors, an international round-robin test (RRT) has been carried out under the programme of VAMAS activity, for which eight research groups participated. The present RRT made the following guideline clear for assessing the mechanical property of Ag/Bi2223 multifilamentary tapes. Owing to the constitution of the brittle superconductive oxide layer embedded in the ductile metal matrix, the stress–percentage extension (R–A) curve shows a three-stage behaviour, that is, the true elastic region is very narrow and is followed by the quasi-elastic region before reaching the macroscopic plastic region. For assessing the elastic constant, it is recommended to look for the maximum slope carefully by enlarging the initial part of the R–A curve. The following three quantities, elastic constant, yield strength and tensile strength, can be reasonably determined with good accuracy by the procedure reported in this paper. The percentage extension after fracture is, however, excluded from the standard procedure, because it scatters to a great extent owing to the nature of the test sample as well as the experimental limitation.

Adaptation and harmonisation of standard testing methods for mechanical properties of low-density polyethylene (LDPE) films

In the framework of a research project carried out at a European level, a preliminary phase with intercomparisons between measured critical mechanical properties and methods has been completed. The aim was to achieve a satisfactory degree of harmonisation in the testing procedures used by the participants and adapt appropriately the corresponding standard testing methods. The recommended methods for testing the mechanical properties of greenhouse polyethylene films are presented. Following the procedure described in a relevant standard for tensile properties, it was shown that it is very important to define appropriately the whole set of parameters involved in the test. In addition, special adaptation of the equipment used is required. The problems encountered during this work led to the redefinition and modifications of several parameters involved in the procedure of measuring specific tensile properties. Harmonisation of the testing methods for impact and initial tear resistance proved to be more readily obtained. However, some parameters entering the corresponding measuring procedures had to be adapted. In general, harmonisation has been achieved regarding the measurement of the specific mechanical properties.

Standard testing methods for mechanical properties and degradation of low density polyethylene (LDPE) films used as greenhouse covering materials: a critical evaluation

LDPE films are currently the most widespread greenhouse covering material in the countries of the Mediterranean region. Taking into account the size of this market, the effect of the material performance on the greenhouse production as well as the related environmental impact problems arising from its disposal, the standardization of the testing of these materials should have already been achieved. However, there are no standard methods available in the European Union for testing LDPE greenhouse films. Furthermore, for predicting the useful lifetime of such films both the critical effect of the various climatic conditions and the effect of the harsh greenhouse micro-environment on their properties should be taken into account. In this paper the various methods for testing the mechanical properties of greenhouse polyethylene films will be presented and discussed critically. Also, the factors affecting ageing of LDPE used as greenhouse covering are presented, including methods for inducing ageing and testing methods in order to probe ageing.

Study on Test Method of Mechanical Properties for Thin Plates and Fine Wires for Spring use

Study on Test Method of Mechanical Properties for Thin Plates and Fine Wires for Spring use

高分子系先進複合材料の力学特性試験法標準化

高分子系先進複合材料の力学特性試験法標準化