Journal articles: 'Paper Elastic properties Testing'

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Darnbrough, J. E., S. Mahalingam, and Peter E. J. Flewitt. "Micro-Scale Cantilever Testing of Linear Elastic and Elastic-Plastic Materials." Key Engineering Materials 525-526 (November 2012): 57–60. http://dx.doi.org/10.4028/www.scientific.net/kem.525-526.57.

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t is increasingly a requirement to be able to determine the mechanical properties of materials: (i) at the micro-scale, (ii) that are in the form of surface coatings and (iii) that have nanoscale microstructures. As a consequence micro-scale testing is an important tool that has been developed to aid the evaluation of the mechanical properties of such materials. In this work cantilever beam specimens (typically 2μm by 2μm by 10μm in size) have been prepared by gallium ion milling and then deformed in-situ within a FEI Helios Dual Beam workstation. The latter is achieved using a force probe with a geometry suitable for loading the micro-scale test specimens. Thus force and displacement can be measured together with observing the deformation and fracture of the individual specimens. This paper considers the evaluation of the mechanical properties in particular elastic modulus, yield strength and fracture strength of materials that result in relatively large deflections to the micro-scale cantilever beams. Two materials are considered the first is linear elastic single crystal silicon and the other elastic-plastic nanocrystalline (nc) nickel. The results are discussed with respect to the reproducibility of this method of mechanical testing and the evaluated properties are compared with those derived by alternative procedures.

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Park, Na Young, Young Chan Ko, Lili Melani, and Hyoung Jin Kim. "Mechanical properties of low-density paper." Nordic Pulp & Paper Research Journal 35, no. 1 (March 26, 2020): 61–70. http://dx.doi.org/10.1515/npprj-2019-0052.

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AbstractFor the mechanical properties of paper, tensile testing has been widely used. Among the tensile properties, the tensile stiffness has been used to determine the softness of low-density paper. The lower tensile stiffness, the greater softness of paper. Because the elastic region may not be clearly defined in a load-elongation curve, it is suggested to use the tensile modulus which is defined as the slope between the two points in the curve. The two points which provide the best correlation with subjective softness evaluation should be selected. Low-density paper has a much lower tensile strength, but much larger elongation at the break. It undergoes a continuous structural change during mechanical testing. The degree of the structural change should depend on tensile conditions such as the sample size, the gauge length, and the rate of elongation. For low-density paper, the tensile modulus and the tensile strength should be independent of each other. The structure efficiency factor (SEF) is defined as a ratio of the tensile strength to the tensile modulus and it may be used a guideline in developing superior low-density paper products.

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Wang, H. X., Jing He Wang, and Shen Dong. "Nanoindentation Size Effect of KDP Crystal by Instrumented Indentation Testing." Key Engineering Materials 364-366 (December 2007): 188–92. http://dx.doi.org/10.4028/www.scientific.net/kem.364-366.188.

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Indentation tests and single-point scratch tests are probably the simplest methods of measuring the elastic, plastic and fracture behavior of brittle materials. In this paper, the nearsurface mechanical properties of KDP single crystal have been investigated including the elasticity like Young’s modulus E, and the plasticity like the hardness H. These material properties can be used to predict the material responses in optical manufacturing operations. Hardness and elastic modulus on different crystal plane of KDP single crystal have been examined under different loads by nanoindentation test, and the influence of the indentation load on hardness and elastic modulus have been also analyzed systematically. The results show the nanoindentation size effect, that is, the hardness and elastic modulus increase as the indentation load decreases. The hardness and elastic modulus have strong anisotropy in the different crystallographic orientation of the same crystal plane.

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Lin, Yu Hua, and Chia Lung Chang. "Inverse Method Based on Modal Vibration Testing for Characterizing the Elastic Properties." Advanced Materials Research 83-86 (December 2009): 198–205. http://dx.doi.org/10.4028/www.scientific.net/amr.83-86.198.

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This paper presents a inverse method to derive the material properties from the resonance frequencies of a free-edge test specimen based on modal vibration test. A mixed numerical experimental identification procedure is used for this purpose. Finite element models of the test plate is simultaneously updating and reproduces the updating frequencies, then optimal procedure is running. The sum of the squared differences between the experimental and the finite element method numerical resonance frquencies is the objective function. To seek practical solutions, here presents a global optimization method--simulated annealing method for the determination of the elastic properties. The inverse method is applied to determine the elastic constants of aluminum , carbon/epoxy , Glass/PP composite material and double coated steel plate. The results indicate that the method can obtain very accurate elastic constants for aluminum , Glass/PP , carbon/epoxy composite material ,but for double coated steel plate , if the individual layer of the three different layers is as isotroptic material having six elastic constants , the method can obtain very accurate results , but if it is as transversely isotropic material having twelve elastic constants, the evaluating elastic constants are bad.

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Kim, J., W. Jung, C. H. Jo, J. Shelton, and W. Craft. "Mechanical properties of cellulose-based electro-active paper." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, no. 4 (April 1, 2008): 577–83. http://dx.doi.org/10.1243/09544062jmes652.

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Mechanical properties of cellulose-based electro-active paper (EAPap) are characterized in this work. Cellulose-based EAPap has been studied as a potential actuator concept, as a result of its low actuation voltage, lightweight, low power consumption, biodegradability and low cost. EAPap is made from cellulose paper, coated with thin electrically conducting electrodes. This EAPap shows a reversible and reproducible bending movement as well as a longitudinal displacement under electric field excitation. However, the EAPap is a complex anisotropic material, which has not been extensively characterized. It is important to have extended property data for EAPap so that the actuator performance can be optimized, and this requires additional material testing. Our material test results show that EAPap has two distinct elastic constants. The initial Young's modulus of EAPap is in the range of 4–9 GPa, which is higher than other polymer materials. This modulus is also orientation dependent, which may be associated with the piezoelectricity of the EAPap materials. Another important property is that the dynamically induced mechanical strains of these materials exhibit linear creep behaviour as confirmed by constant stress and low frequency cyclic loading tests. From scanning electron microscope investigations, cellulose EAPap exhibits a layered, anisotropic cellulose macromolecular structure that exhibits both elastic and plastic deformations, as well as substantial temperature and humidity dependence.

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Jankovic-Castvan, Ivona, Slavica Lazarevic, Dusica Stojanovic, Predrag Zivkovic, Rada Petrovic, and Djordje Janackovic. "PVB/sepiolite nanocomposites as reinforcement agents for paper." Journal of the Serbian Chemical Society 81, no. 11 (2016): 1295–305. http://dx.doi.org/10.2298/jsc160506067j.

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In order to improve the mechanical properties of paper, 1, 3 and 5 wt.% of sepiolite were dispersed in a poly(vinyl butyral) (PVB) matrix and coated onto the surface of schrenz (110 g m-2). Deagglomerated sepiolite nanofibers in PVB matrix on paper surface were observed by scanning electronic microscopy. The glass transition temperature of schrenz with PVB/sepiolite coatings was not changed with increasing content of sepiolite. Two different methods were used to evaluate the mechanical properties of the paper sample reinforced with PVB/sepiolite nanocomposites: tensile testing and nanoindentation. The values of breaking force and tensile energy absorption of the reinforced paper samples obtained by tensile testing were increased by up 10 %. The values of the reduced elastic modulus and hardness obtained by nanoindentation were increased by up to 78 %. The best improvement of the mechanical properties was shown by the paper sample coated with PVB/3 wt.% sepiolite nanocomposite.

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Shcherbakov, Y. M., and V. N. Frolov. "Method of plastics endurance testing." Izvestiya MGTU MAMI 8, no. 1-3 (May 10, 2014): 28–34. http://dx.doi.org/10.17816/2074-0530-67558.

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The authors propose a method for testing plastics endurance under plane transverse bending with a given cyclic deformation. The paper describes the relations for the calculation of the amount of deflection, rotation angles of the end parts of a sample and the technological gap d between the pins in movable supports and a model for the transverse bending of a sample, the properties of which are given by linear-elastic and nonlinear elastic (according to power law) models. To determine the dependence of stresses on the number of cycles before sample failure, the authors propose the method for estimating stress with the use of the dependence of stresses on the number of cycles before failure and stress-deformation dependence, obtained in quasi-static tests under "instantaneous" loading.

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Mokhtari, Mehdi, Matt M. Honarpour, Azra N. Tutuncu, and Gregory N. Boitnott. "Characterization of Elastic Anisotropy in Eagle Ford Shale: Impact of Heterogeneity and Measurement Scale." SPE Reservoir Evaluation & Engineering 19, no. 03 (June 1, 2016): 429–39. http://dx.doi.org/10.2118/170707-pa.

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Summary Heterogeneity and anisotropy were characterized in some Eagle Ford shale samples at various scales by use of scanning-electron-microscopy (SEM) imaging, computed-tomography (CT) scanning, and compressional-velocity scanning. Triaxial testing on 1-in.-diameter and 3-in.-diameter core samples and well-log analysis were used to calculate elastic properties by using vertical transverse isotropic modeling. Correlations between the stiffness coefficients and the correlations between static and dynamic properties from laboratory tests were applied to well-log analysis to improve the calculation of minimum horizontal stress. This paper provides the elastic properties of the Eagle Ford shale at various measurement scales. The paper also elaborates the role of heterogeneity in laboratory testing of shale reservoirs.

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Pazdera, Lubos, Libor Topolar, Jaroslav Smutny, and Kristyna Timcakova. "Nondestructive Testing of Advanced Concrete Structure during Lifetime." Advances in Materials Science and Engineering 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/286469.

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The paper reports on measurements and analysis of the measurements during hardening and drying of specimens using selected acoustic nondestructive testing techniques. An integrated approach was created for better understanding of the relations between the lifetime cycle and the development of the mechanical properties of concrete. Acoustic emission, impact echo, and ultrasonic techniques were applied simultaneously to the same mixtures. These techniques and results are presented on alkali-activated slag mortars. The acoustic emission method detects transient elastic waves within the material, caused by the release of cumulated stress energy, which can be mechanical, thermal, or chemical. Hence, the cause is a phenomenon which releases elastic energy into the material, which then spreads in the form of an elastic wave. The impact echo method is based on physical laws of elastic stress wave propagation in solids generated by mechanical impulse. Ultrasonic testing is commonly used to find flaws in materials or to assess wave velocity spreading.

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Smirnov, Alexander, Evgeniya Smirnova, and Yulia Khudorozhkova. "Constructing a two-level computational model of cross-ply fiberglass-reinforced plastic from micromechanical testing." Polymers and Polymer Composites 30 (January 2022): 096739112211124. http://dx.doi.org/10.1177/09673911221112414.

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This paper deals with solving the problem of constructing two-level computational models relating the stress-strain state at the microscale to the stress-strain state of the structural component at the macroscale for layered polymer composite materials with unidirectional fiber stacking in a monolayer. The paper presents a two-level computational mechanical model of a ten-layer cross-ply fiberglass-reinforced polymer composite with (0/90) laying patterns. The model is based on microindentation data. The model is constructed using the finite element method. The constructed model has allowed us to predict the elastic properties of the composite and to calculate stresses at the microscale and macroscale levels of a specimen prior to fracture under tensile conditions. The elastic properties of the polymer composite material predicted by the computational model are compared with the properties obtained from real experiments. Calculated for fiberglass, the elasticity modulus and Poisson’s ratio are 31 GPa and 0.11, respectively. Similar elastic properties obtained from real experiments are 28 GPa and 0.10. The technique used in the paper can be applied to computational experiments with an actual structural component made of a multilayer polymer composite in order to determine the stress-strain state at the micro- and macroscale under external mechanical impact on the structure.

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Yap, Yee Ling, William Toh, Rahul Koneru, Zhong Yang Chua, Kehua Lin, Kirk Ming Yeoh, Chin Mian Lim, et al. "Finite element analysis of 3D-Printed Acrylonitrile Styrene Acrylate (ASA) with Ultrasonic material characterization." International Journal of Computational Materials Science and Engineering 08, no. 01 (March 2019): 1950002. http://dx.doi.org/10.1142/s2047684119500027.

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This paper investigates the orthotropic properties of Fused Deposition Modeling (FDM)-printed Acrylonitrile Styrene Acrylate (ASA) material with different raster configurations. The elastic properties were determined using a non-destructive ultrasonic technique. This technique allows us to deduce the orthotropic elastic constants from the material density and the velocities of the longitudinal and shear waves propagating through the material along different directions. Tensile tests were performed in addition to ultrasonic tests to obtain the yield properties of the ASA material and to validate the elastic constants determined by the ultrasonic tests, which have shown very close correspondence. Finally, numerical verification was performed by comparing the experimental results of the three-point and four-point bending tests with the finite element simulation results which have as input the material properties from the ultrasonic testing. The simulation results have shown excellent agreement with the experimental results, implying that the material properties obtained from the ultrasonic testing were highly accurate comparing to the actual orthotropic elastic properties of the 3D-printed ASA material.

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Matysík, Michal, Ladislav Carbol, Zdenek Chobola, Richard Dvořák, and Iveta Plšková. "Comparison of Ultrasonic Methods for Thermally Damaged Concrete Nondestructive Testing." Key Engineering Materials 776 (August 2018): 86–91. http://dx.doi.org/10.4028/www.scientific.net/kem.776.86.

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Behaviour of concrete under elevated temperatures is very complex. There is a change of mechanical and physical parameters with temperature. In this paper we study the relations of thermal damage processes in concrete and parameters obtained by different ultrasonic methods. The concrete specimens were heated in programmable laboratory furnace. Selected temperature (200°C, 400°C, 600°C, 800°C, 1000°C and 1200°C) were maintained for 60 minutes. The first ultrasonic measurement technique in this paper was Ultrasonic Pulse Velocity method. The pulse velocity in a concrete depends on its density and its elastic properties. Therefore, it is possible to deduce the quality and the compressive strength of the concrete from the ultrasonic pulse velocity. The second ultrasonic measurement technique in this paper uses broadband pulse-compression signal, with variable amplitude to measure the change of fundamental frequency. This method is based on Nonlinear Elastic Wave Spectroscopy. Nonlinear Elastic Wave Spectroscopy methods takes advantage of the fact, that nonlinearities in material manifest themselves as a resonant frequency shifts and harmonics or dumping coefficients changes. The progress of nondestructive testing parameters was confirmed by results from the destructive tests.

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Pan, Chun Xiang, Xiao Yan Qi, Guang Zhao, and Xu Zhuo Guo. "The Test and Analysis of Nano Mechanical Properties for Dragonfly Wing." Applied Mechanics and Materials 574 (July 2014): 271–74. http://dx.doi.org/10.4028/www.scientific.net/amm.574.271.

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nanomechanical testing system in this paper has been applied to get elastic modulus and hardness of dragonfly wing, and showing their gradient changes along the wing, and also analyzing the mechanical properties in nanodimension. It is significant to make a further research for specific biological functions of dragonfly wing.

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Nohava, Jiri, Petr Haušild, David Gichangi Axelson, and Gwenaél Bolloré. "Mechanical Properties of Aluminum Alloys by Instrumented Indentation: Case Study on Almigo Hard." Key Engineering Materials 586 (September 2013): 59–62. http://dx.doi.org/10.4028/www.scientific.net/kem.586.59.

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This paper presents a case study of instrumented indentation for assessment of mechanical properties of a specific Almigo Hard aluminium alloy. It shows that conventional microhardness is not suitable for local testing of this material and that instrumented indentation can reveal significantly more information about the tested material such as Young’s modulus and elastic-plastic characteristics. The study compares mechanical and elastic-plastic properties of the Almigo Hard, aircraft Al alloy and reactor vessel ferritic steel by single peak load and cyclic indentations in order to demonstrate superior properties of the Almigo Hard alloy.

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Chen, Jie, Xiaoyu Wang, Xu Yang, Li Zhang, and Hong Wu. "Application of Air-Coupled Ultrasonic Nondestructive Testing in the Measurement of Elastic Modulus of Materials." Applied Sciences 11, no. 19 (October 4, 2021): 9240. http://dx.doi.org/10.3390/app11199240.

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It is difficult to measure elastic modulus simply and accurately in the testing of mechanical properties of materials. Combined with static tensile method, this paper presents a method for measuring elastic modulus of materials based on air-coupled ultrasonic nondestructive testing. Firstly, the 1–3 piezoelectric composite material and the matching material of low acoustic impedance are self-made, and 400 kHz air-coupled ultrasonic transducer is fabricated. Then, the performance of the transducer is tested, and the insertion loss and bandwidth of −6 dB are −33.5 dB and 23.4%, respectively. Compared with the traditional instrument for measuring elastic modulus, the measurement of elastic modulus of carbon steel rod material is realized in this paper, and the measured results are in agreement with the accepted value. In addition, from the angle of relative uncertainty, how to reduce the measurement error by improving the device is analyzed. It can be shown that the method has high linearity, high symmetry, and good stability and repeatability. This paper provides a new way for the selection and design of measuring instrument components.

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Kravcov, Alexander N., Pavel Svoboda, Adam Konvalinka, Elena B. Cherepetskaya, Alexsander A. Karabutov, Dmitry V. Morozov, and Ivan A. Shibaev. "Laser-Ultrasonic Testing of the Structure and Properties of Concrete and Carbon Fiber-Reinforced Plastics." Key Engineering Materials 722 (December 2016): 267–72. http://dx.doi.org/10.4028/www.scientific.net/kem.722.267.

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This paper discusses the possibility of studying composite materials by non-destructive laser-ultrasonic testing technique. Concrete samples and carbon-epoxy composites were examined, defects located and elastic wave velocities measured. The internal structure of the samples was visualized in 2D images.

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Li, Jin Kui, Lei Zhang, Wen Hua Yang, and Ming Liang Sun. "Elastic Wave Measurement Technology and its Engineering Application." Advanced Materials Research 655-657 (January 2013): 795–800. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.795.

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The velocity and amplitude of elastic wave in the rock mass are dependent on the physical and mechanical properties, as well as the structural and stress state of rock mass. The elastic wave testing technique has become one of the most important approaches in geological engineering and rock mechanics. In order to enhance the analysis and application of elastic wave testing technique, the present paper investigates the elastic wave propagation pattern both in laboratory and in field. The lab tests focus on wave velocity in rock mass and the field work focus on the measurement of longitudinal wave velocity by using double-service elastic wave test. The field tests also include the testing of the roadway surrounding rock loose circle on the edge of underground chamber construction site. The study profiles the rock mass’s elastic wave dynamic characteristics, clarifies the rock mass structures, assess the property of the rock mass surrounding the subway. All these are of great significance to the underground chamber and tunneling engineering design and construction.

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Al-Hunaidi, M. O. "Insights on the SASW nondestructive testing method." Canadian Journal of Civil Engineering 20, no. 6 (December 1, 1993): 940–50. http://dx.doi.org/10.1139/l93-126.

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Spectral analysis of surface waves (SASW) is a nondestructive and in-situ method used for determining the thickness and elastic properties of pavement and soil sites using the dispersion characteristics of surface waves. In this paper, computer simulations of actual surface wave field tests are used to clarify errors that may arise in experimental dispersion curves of pavement sites when the usual test and data analysis procedures of the SASW method are followed. Two aspects of these procedures are considered: (i) relative phase angle unwrapping and (ii) source-to-near-receiver distance. The results of these simulations reveal that the currently used procedures may lead to erroneous results for some sites; the simulations offer valuable insights on the underlying causes. An overview of the theoretical aspects and field procedures of the surface wave method is briefly presented. Key words: surface waves, nondestructive testing, pavements, soils, elastic modulus.

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Alfano, Marco, Leonardo Pagnotta, and Giambattista Stigliano. "Identifying Elastic Properties of Isotropic Materials by Finite Element Analyses and Vibration Data." Key Engineering Materials 345-346 (August 2007): 1327–30. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1327.

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The use of non destructive techniques for the elastic characterization of isotropic materials is continuously increasing and those based on the modal vibration testing of plate-like specimens is very widespread. In the present paper, an optimized search procedure is proposed which allows the material constants of isotropic plates to be non-destructively identified from vibration testing data and using finite element analyses. The identification process is performed by an optimizing algorithm in which the error function to be minimized depends on the difference between the natural frequencies obtained by finite element analyses and the measured ones. In order to verify the proposed identification procedure a comparison with the results reported in literature has been made.

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Tipalin, S. A., N. F. Shpunkin, and B. Y. Saprykin. "Determination of properties of sheet damping material with viscoelastic coupling layer during shear deformation." Izvestiya MGTU MAMI 8, no. 2-2 (March 20, 2014): 99–103. http://dx.doi.org/10.17816/2074-0530-67716.

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The paper proposes a scheme of testing with a uniform deformation for measuring the properties of multi-layer material with viscoelastic connective layer while performing experiments on the shift. Experimental results showing the features of large shear deformation of a viscoelastic layer and the elastic layer in the samples are provided.

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Beliaev, Anton Y., Olga S. Gileva, Andrew L. Zuev, and Maria A. Muraveva. "Experimental Studies of Elastic Properties of Dental Enamel and Photopolymer Used for early Caries Treatment." Key Engineering Materials 592-593 (November 2013): 358–61. http://dx.doi.org/10.4028/www.scientific.net/kem.592-593.358.

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The paper is concerned with the study of the elastic properties of dental enamel and its destruction by a microindentation technique. A series of experiments were performed to find differences in the mechanical properties of healthy and diseased dental enamel. It has been found that the times of dental enamel destruction in healthy and carious areas under a constant force are different. The effect of an infiltrated photopolymer on the hardness and elastic modulus of dental enamel was investigated by microindentation testing. A comparative analysis of the features of healthy, damaged by caries and treated by photopolymer enamel was carried out.

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Zhu, Huai Liang, Li Feng Yu, Jing Ni, Xue Wang, and Ren An Luo. "Testing and Evaluation of Mechanical Properties for Anisotropic Engineering Materials with Varied Loads." Key Engineering Materials 544 (March 2013): 471–75. http://dx.doi.org/10.4028/www.scientific.net/kem.544.471.

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This paper is aimed at investigating the influence of load-bearing style on the mechanical behavior of anisotropic engineering materials. The study on elastic constants and failure forms of materials will be presented under different loading condition. Firstly, the mechanical properties of unidirectional holey laminated materials are discussed based on the uniaxial tensile tests. The equivalent elastic modulus, Poisson’s ratio and shear modulus are obtained, and the pattern and mechanism of failure are analyzed. Then, the biaxial tensile tests are carried out for PVC orthotropic membrane materials with different stress ratio between the warp and weft direction. A comparison of limit strengths under biaxial loadings is given with that in uniaxial loading case. Finally, the dynamical behaviors of shape memory alloy (SMA), iron wire, and rubber composite as well as compound rubber are studied respectively by impact-tension tests. The failure forms, energy dissipation ratio and impact-tension toughness of materials are analyzed. It is shown that the mechanical properties and failure pattern of anisotropic materials have much to do with the load-bearing styles. It agrees well with actual properties of anisotropic material used in engineering structures.

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Setiyana, Budi, Sugiyanto, J. Jamari, and M. Khafidh. "Numerical investigation on the elastic modulus of rubber-like materials by a rigid ball indentation technique." MATEC Web of Conferences 204 (2018): 07002. http://dx.doi.org/10.1051/matecconf/201820407002.

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The indentation technique has been practically proven to be useful in determining mechanical properties of materials, such as hardness and elastic modulus for rubber-like materials (elastomers). However, tensile test method is often conducted because of obtaining the mechanical strength in addition to the elastic modulus of the elastomer. In this paper, a numerical study is proposed to investigate the elastic modulus of the elastomer by applying Finite Element Analysis (FEA). With the availability of Strain Energy Function (SEF) data from the material testing, the investigation is carried out by indentation technique for Natural Rubber (NR) and Styrene Butadiene Rubber (SBR). On the rubber surface, a rigid ball indenter is pressed under specified indentation force and the contact depth resulted is observed. Based on the ASTM (American Society for Testing and Materials) formulation, the elastic modulus from the indentation technique can be estimated. In general, results show that the elastic modulus obtained from the indentation technique agree with the tensile test results. Thus, the proposed numerical method is validly applied in determining the elastic modulus.

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Zhao, Li Jie, and Qiang Fu. "Parametric Study of EAPap Material Properties." Advanced Materials Research 430-432 (January 2012): 242–46. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.242.

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Cellulose paper is used as base material for so-called electroactive papers (EAPap) actuator. EAPap is a complex anisotropic material, which has not been extensively characterized and additional basic testing is required before developing application devices from EAPap. Mechanical properties of EAPap were investigated in this work under different environmental conditions (humidity, temperature, and electrical field) and configurations. It shows viscoelastic effect and exhibits two distinct elastic and plastic modulus connected by a bifurcation point. Through tests, environment and configuration effects on EAPap are obtained to researchers and designers interested in the field of smart materials and EAP.

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Baciu, Florin, Daniel Vlăsceanu, and Anton Hadăr. "The Influence of 3D Printing Parameters on Elastic and Mechanical Characteristics of Polylactide." Materials Science Forum 957 (June 2019): 483–92. http://dx.doi.org/10.4028/www.scientific.net/msf.957.483.

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The purpose of this paper is to evaluate the influence of 3D printing parameters (i.e. print speed, infill density, infill patterns) on the elastic and mechanical properties (i.e. Young modulus, yield limit, ultimate tensile strength). These properties have been determined experimentally on different specimens subjected to tensile loading using a universal testing machine INSTRON 8872. For these experimental investigations, the test specimens were manufactured in accordance to ASTM standards, modifying the following printing parameters: print speed, infill density, infill patterns. The influence of printing parameters on elastic and mechanical properties is necessary for a better understanding of the material behavior necessary in modelling and design of some type of structures manufactured using 3D printing method.

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Suciu, Oana, Liviu Bereteu, Gheorghe Drăgănescu, and Teodora Ioanovici. "Determination of the Elastic Modulus of Hydroxyapatite Doped with Magnezium through Nondestructive Testing." Advanced Materials Research 814 (September 2013): 115–22. http://dx.doi.org/10.4028/www.scientific.net/amr.814.115.

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In this paper there are presented determination methods of longitudinal elasticity modulus based on processing and analysis of vibration signals which are the results of an impulse from a small rigid ball applied on some samples of hydroxyapatite with discoid form. Hydroxyapatite is a bioactive bioceramics used, usually in implants, rods and screws covering, in order to allow human tissue to adhere to implant surface. In order to improve mechanical properties of hydroxyapatite it is doped with magnesium. This chemical element exists in normal bone tissue; it doesnt create any compatibility problem and has a stabilizing role in heat treatments stopping undesirable phase transformations.

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Ragauskas, Paulius, and Rimantas Belevičius. "IDENTIFICATION OF MATERIAL PROPERTIES OF COMPOSITE MATERIALS." Aviation 13, no. 4 (December 31, 2009): 109–15. http://dx.doi.org/10.3846/1648-7788.2009.13.109-115.

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Present paper describes the facilities of composite material properties identification technique using specimen vibration tests, genetic algorithms, finite elements analysis and specimen shape optimization. In identification process the elastic constants in a numerical model is updated so that the output from the numerical code fits the results from vibration testing. Main problem analysed in this paper is that Poisson's ratio is the worst determined elastic characteristic due to its low influence on specimen eigenfrequencies. It is shown that it is possible to increase its influence by choosing specific test specimen characteristics (side aspect ratio, orthotropy angle, etc.) via optimization routine. In this paper are presented test results of some experiments wherein glass‐epoxy and carbon‐epoxy material properties were identified. Santrauka Straipsnyje aprašomas kompozitiniu medžiagu tamprumo charakteristiku identifikavimo metodas naudojant bandiniu vibracinius bandymus, genetinius algoritmus, baigtiniu elementu metoda ir bandiniu formos optimizavima. Identifikavimo metu tamprumo charakteristikos skaitmeniniame modelyje yra atnaujinamos tol, kol skaitinio eksperimento rezultatai nustatytu tikslumu sutampa su vibracinio bandymo rezultatais. Šio straipsnio pagrindinis uždavinys yra padidinti Puasono koeficiento identifikavimo tiksluma, kadangi šis, palyginti su kitu tamprumo charakteristiku identifikavimo tikslumais, yra menkas del ypač mažos koeficiento itakos bandinio tikriniams dažniams. Darbe parodyta, kad imanoma padidinti Puasono koeficiento itaka optimizavimo procedūromis, pasirenkant konkrečias bandinio savybes (kraštiniu proporcijas, ortotropijos kampa ir t.t.). Pateikiami keleto stiklo ir anglies pluoštais armuotu kompozitiniu medžiagu tamprumo charakteristiku identifikavimo rezultatai.

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Němeček, Jiří, and Vlastimil Kralik. "Local Mechanical Characterization of Metal Foams by Nanoindentation." Key Engineering Materials 662 (September 2015): 59–62. http://dx.doi.org/10.4028/www.scientific.net/kem.662.59.

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This paper deals with microstructure and micromechanical properties of two commercially available aluminium foams (Alporas and Aluhab). Since none of the materials is available in a bulk and standard mechanical testing at macro-scale is not possible the materials need to be tested at micro-scale. To obtain both elastic and plastic properties quasi-static indentation was performed with two different indenter geometries (Berkovich and spherical tips). The material phase properties were analyzed with statistical grid indentation method and micromechanical homogenization was applied to obtain effective elastic wall properties. In addition, effective inelastic properties of cell walls were identified with spherical indentation. Constitutive parameters related to elasto-plastic material with linear isotropic hardening (the yield point and tangent modulus) were directly deduced from the load–depth curves of spherical indentation tests using formulations of the representative strain and stress introduced by Tabor.

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Zhu, Xuefeng, Longkun Xu, Xiaochen Liu, Jinting Xu, Ping Hu, and Zheng-Dong Ma. "Theoretical prediction of mechanical properties of 3D printed Kagome honeycombs and its experimental evaluation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 18 (July 16, 2019): 6559–76. http://dx.doi.org/10.1177/0954406219860538.

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Kagome honeycomb structure is proved to incorporate excellent mechanical and actuation performances due to its special configuration. However, until now, the mechanical properties of 3D printed Kagome honeycomb have not been investigated. Hence, the objective of this work is to explore some mechanical properties of 3D-printed Kagome honeycomb structures such as elastic properties, buckling, and so on. In this paper, the analytical formulas of some mechanical properties of Kagome honeycombs made of 3D-printed materials are given. Effective elastic moduli such as Young's modulus, shear modulus, and Poisson's ratio of orthotropic Kagome honeycombs under in-plane compression and shear are derived in analytical forms. By these formulas, we investigate the relationship of the elastic moduli, the relative density, and the shape anisotropy–ratio of 3D-printed Kagome honeycomb. By the uniaxial tensile testing, the effective Young's moduli of 3D printed materials in the lateral and longitudinal directions are obtained. Then, by the analytical formulas and the experimental results, we can predict the maximum Young's moduli and the maximum shear modulus of 3D-printed Kagome honeycombs. The isotropic behavior of 3D-printed Kagome honeycombs is investigated. We also derived the equations of the initial yield strength surfaces and the buckling surfaces. We found that the sizes of the buckling surfaces of 3D printed material are smaller than that of isotropic material. The efficiency of the presented analytical formulas is verified through the tensile testing of 3D printed Kagome honeycomb specimens.

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Cui, Hong Zhi, and Feng Xing. "The Study of Mechanical Properties of Structural Lightweight Concrete." Advanced Materials Research 97-101 (March 2010): 1620–23. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.1620.

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Many investigations have been conducted on compressive strength of lightweight aggregate concretes (LWAC), but there are few experimental studies on the relationship between compressive strength, bond strength and elastic modulus of LWAC. In this paper, the specimens of twenty kinds of LWACs with different mix proportions were made. Properties of compressive strength, bond strength and modulus of elasticity of the LWACs were tested. Based on the testing resulting, equations for relationship between bond strength and compressive strength of the LWAC were established. For LWAC modulus of elasticity, the experimental results of this study can fit well with predicted equation of ACI 318

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Guo, Y. B., and C. R. Liu. "Mechanical Properties of Hardened AISI 52100 Steel in Hard Machining Processes." Journal of Manufacturing Science and Engineering 124, no. 1 (April 1, 2001): 1–9. http://dx.doi.org/10.1115/1.1413775.

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This paper provides an approach using tensile tests at elevated temperatures to estimate mechanical properties of the work material for both elastic and plastic deformations in a broad range of strain, strain rate, and temperature in machining. The proposed method has been applied to estimate mechanical properties of hardened AISI 52100 steel in hard machining. Tensile testing is shown capable of estimating the mechanical properties of both elastic and plastic regions with large strains at elevated temperatures. Flow stresses at high strain rates in machining can be obtained by extrapolating the data from tensile tests by using the velocity-modified temperature. Flow stress data from tensile and cutting tests is consistent with regard to the velocity-modified temperature. Temperature is the dominant factor of mechanical properties of this material, while the effect of strain rate is secondary. Cutting forces and chip geometry predicted by the 3D FEM simulation of hard turning using the material property data obtained from the developed method agree well with the experimental data.

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Frühmann, R. K., S. Sambasivam, Janice M. Dulieu-Barton, and S. Quinn. "Material Properties for Quantitative Thermoelastic Stress Analysis of Composite Structures." Applied Mechanics and Materials 13-14 (July 2008): 99–104. http://dx.doi.org/10.4028/www.scientific.net/amm.13-14.99.

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The sensitivity of the thermoelastic response to variations in the fibre volume fraction, resin material and manufacturing route is assessed. To quantify any effects a comprehensive materials testing programme has been conducted to obtain coefficients of thermal expansion, specific heat, density and the elastic properties, which is described in detail in the paper. The work is focused on attempting to ascertain if the source of the response is from the isotropic resin rich layer or from the orthotropic substrate. It is also demonstrated that small variations in material properties can have a significant effect on the calculated thermoelastic response.

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Wei, Chen Guang, Yi Wang Bao, Zheng Quan Liu, and Dong Wang. "Influence of Specimen Size on the Impulse Excitation Technique." Key Engineering Materials 633 (November 2014): 459–62. http://dx.doi.org/10.4028/www.scientific.net/kem.633.459.

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The Impulse Excitation technique is a nondestructive and very convenient testing method. It could be applied at different circumstances such as high temperatures, low temperatures and controlled humidity. The Impulse Excitation technique is based on the analysis of the vibration of a test sample after it was impulse excited. The elastic properties of a test specimen are related to its mechanical resonance frequency. In this paper, the regular of resonance frequency changed with specimen’s size was discussed. Elastic modulus of glass with different length, width and thickness were measured, and ceramic composite material with small size was tested. The results indicate that the resonance frequency of specimen changed with its size regularly, and the specimen with small size has poor accuracy of elastic modulus measurement.

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Pandzic, Adi, and Damir Hodzic. "Mechanical properties comparison of PLA, tough PLA and PC 3D printed materials with infill structure – Influence of infill pattern on tensile mechanical properties." IOP Conference Series: Materials Science and Engineering 1208, no. 1 (November 1, 2021): 012019. http://dx.doi.org/10.1088/1757-899x/1208/1/012019.

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Abstract One of the advantages provided by fused deposition modelling (FDM) 3D printing technology is the manufacturing of product materials with infill structure, which provides advantages such as reduced production time, product weight and even the final price. In this paper, the tensile mechanical properties, tensile strength and elastic modulus, of PLA, Tough PLA and PC FDM 3D printed materials with the infill structure were analysed and compared. Also, the influence of infill pattern on tensile properties was analysed. Material testing were performed according to ISO 527-2 standard. All results are statistically analysed and results showed that infill pattern have influence on tensile mechanical properties for all three materials.

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Kurakina, Elena, and Sergey Evtiukov. "Impact of static and dynamic loads of vehicles on pavement." E3S Web of Conferences 164 (2020): 03025. http://dx.doi.org/10.1051/e3sconf/202016403025.

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The present paper substantiates urgency of studies on early deterioration of pavement layers and on reasons entailing it. The aim was to investigate static and dynamic loads imposed on a road surface by vehicles in order to detect signs of early deterioration of pavement and understand its reasons. Certain tasks were set: to define diagnostic capacity for performing test works on road surface with the use of static and dynamic loading equipment; to carry out an elastic modulus analysis on the basis of static and dynamic loading tests performed; to assess strength properties of flexible pavement. The paper describes methods for determining strength properties of a road surface with the use of special static and dynamic loading equipment. The authors provide data on diagnostic capacity of tests of a pavement performed with the use of special testing equipment. The paper gives a list of potentials, advantages and fundamental features of the following units of equipment: apparatus for plate bearing tests, Dina-3M, UDN-NK, Dynatest apparatus. The main parameters of equipment for dynamic loading tests are provided. The results of both dynamic and static loading tests performed in Saint Petersburg and the Leningrad region are given. Deflection bowls and elastic modulus were determined. Coefficients of the dynamic elastic modulus being reduced to the static one were calculated. Strength properties of flexible pavement were assessed.

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Al-Rifaie, Hasan, Nejc Novak, Matej Vesenjak, Zoran Ren, and Wojciech Sumelka. "Fabrication and Mechanical Testing of the Uniaxial Graded Auxetic Damper." Materials 15, no. 1 (January 5, 2022): 387. http://dx.doi.org/10.3390/ma15010387.

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Auxetic structures can be used as protective sacrificial solutions for impact protection with lightweight and excellent energy-dissipation characteristics. A recently published and patented shock-absorbing system, namely, Uniaxial Graded Auxetic Damper (UGAD), proved its efficiency through comprehensive analytical and computational analyses. However, the authors highlighted the necessity for experimental testing of this new damper. Hence, this paper aimed to fabricate the UGAD using a cost-effective method and determine its load–deformation properties and energy-absorption potential experimentally and computationally. The geometry of the UGAD, fabrication technique, experimental setup, and computational model are presented. A series of dog-bone samples were tested to determine the exact properties of aluminium alloy (AW-5754, T-111). A simplified (elastic, plastic with strain hardening) material model was proposed and validated for use in future computational simulations. Results showed that deformation pattern, progressive collapse, and force–displacement relationships of the manufactured UGAD are in excellent agreement with the computational predictions, thus validating the proposed computational and material models.

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Fellers, Christer, and Christian Andersson. "Evaluation of the stress-strain properties in the thickness direction - particularly for thin and strong papers." Nordic Pulp & Paper Research Journal 27, no. 2 (May 1, 2012): 287–94. http://dx.doi.org/10.3183/npprj-2012-27-02-p287-294.

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Abstract The performance of the paper in a number of converting operations such as creasing, bending, printing, and plastic coating put great demands on the mechanical properties in the thickness direction of the material. The knowledge of strength, elastic- and plastic behavior in tension and compression in the thickness direction is needed for a comprehensive description of the performance of the material in these operations. In spite of its importance, very few publications deal with the evaluation of the entire tensile stress-strain curve of paper in the thickness direction. A likely reason for this is the intrinsic difficulty of testing a thin, uneven, porous, fibrous and compressible material such as paper with sufficient precision and testing time efficiency. The z-directional strength test is usually performed by fastening the paper by means of double-adhesive tape to metal platens. The platens are fastened in a testing machine and strained to break. The adhesion of the tape is the limiting factors for how strong papers that can be tested. The tape-based method also is expected to have a lower limit in grammage due to the penetration of the adhesive. The aim of the present publication was to show a procedure how to evaluate the entire stress-elongation curve in the z-direction of papers, using a lamination method for fastening the paper to the metal platens. From this curve the z-strength, z-modulus, z-strain at break, zenergy at break and z-fracture energy could be extracted. Such information is, so far, non-existing in the literature.

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Jacquet, Yohan, Vincent Picandet, Damien Rangeard, and Arnaud Perrot. "Gravity induced flow to characterize rheological properties of printable cement-based materials." RILEM Technical Letters 5 (December 29, 2020): 150–56. http://dx.doi.org/10.21809/rilemtechlett.2020.128.

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This paper presents testing methods based on the deformation and fracture of fresh cementitious materials only subjected to their own weight. These new methods are dedicated to the study of cementitious materials designed for 3D printing of concrete in order to verify rheological requirements related to the process. The first testing methods consists in measuring the tip deflection of a fresh cementitious materials, horizontally extruded, and allows for the determination of apparent elastic modulus of the material, while the second test consists in measuring the tensile strength of material filament leaving the nozzle of a vertical downward extruder. Both methods are based on the video capture of the deformation of the materials loaded by gravity, and provide results that are in agreement with tests performed with conventional testing machines (tensile and unconfined compression tests). This work shows the potential of the video capture of the gravity induced deformation of cementitious materials to describe behavior of cementitious materials at fresh state or for the in-line control of the 3D concrete printing process.

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Hall, Andrea K. I., Raymond H. Plaut, and Patricia M. McGuiggan. "Comparing Non-destructive Mechanical Testing Methods for the Assessment of Brittle Papers – The Cantilever, Hanging Pear Loop, and Clamped Fold Tests." Restaurator. International Journal for the Preservation of Library and Archival Material 40, no. 1 (March 26, 2019): 15–34. http://dx.doi.org/10.1515/res-2018-0015.

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Abstract The ability to determine the condition of paper (e.g. its brittleness) and its permanence is a need in libraries and archives. This study investigates various bend tests and applies these tests to aged paper with the goal of finding easy, non-destructive tests to determine the mechanical properties of paper. The cantilever test was previously shown to accurately assess mechanical properties of paper-based materials, such as elastic and bending moduli as well as the bending length. This work investigates the hanging pear loop and clamped fold tests and compares the results with those found with the cantilever test. The results show that the strain and curvature induced by the two tests are much larger than those experienced in the cantilever test. This large strain and curvature induce plastic behaviour and make the hanging pear loop and clamped fold tests inappropriate for use on paper-based materials.

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Li, Ji Bin, Ke Ke Xu, Xin Bo Lin, Xiao Yu Wu, and Guo Li Gao. "Research on the Flow Characteristics of Polymer Injection Molding under Ultrasonic Vibration and Plastics’ Mechanical Strength." Applied Mechanics and Materials 37-38 (November 2010): 1092–100. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.1092.

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In this paper, ultrasonic vibration is adopted and exerted on injection molding in order to improve plastics’ forming ability, and the impact testing is used to analyze different injection parts’ mechanical properties. On the one hand, experiments prove that ultrasonic vibration can increase polymer’s melt flow rate, decrease melt viscosity, and improve injection flowing in mould cavity. On the other hand, the mechanical tests prove that the ultrasonic vibration can improve plastics’ tensile strength, elastic modulus and other mechanical properties. As a result, a weldless ultrasound-assisted injection molding method is recommended.

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Stimpson, B., and Rui Chen. "Measurement of rock elastic moduli in tension and in compression and its practical significance." Canadian Geotechnical Journal 30, no. 2 (April 1, 1993): 338–47. http://dx.doi.org/10.1139/t93-028.

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The moduli of deformation of rock in tension and in compression are generally assumed equal. However, many rocks show different deformation properties when loaded in tension and in compression. This property is usually referred to as bimodularity. In this paper, a new testing technique in which moduli in both tension and compression can be measured on the same specimen in the same compressive loading frame is described. Testing results from halite, potash, granite, and limestone indicate that moduli in compression and in tension are different for at least three of these materials. The new testing technique is validated against the standard uniaxial tension and uniaxial compression tests on potash and halite. Also, results from granite by the new testing technique are comparable with previously published data. The practical significance of rock bimodularity is discussed as well. It is demonstrated that this property significantly influences the deflection and stress distribution in a simple beam problem. Bimodularity also influences the interpretation of indirect rock tension test results and the prediction of roof deflection in underground openings. Ignoring bimodularity overestimates rock tensile strength in most of the indirect rock tension tests and underestimates roof deflection. Key words : rock, elastic modulus, bimodularity, testing technique.

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Du Plessis, Anton, Dean-Paul Kouprianoff, Ina Yadroitsava, and Igor Yadroitsev. "Mechanical Properties and In Situ Deformation Imaging of Microlattices Manufactured by Laser Based Powder Bed Fusion." Materials 11, no. 9 (September 9, 2018): 1663. http://dx.doi.org/10.3390/ma11091663.

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This paper reports on the production and mechanical properties of Ti6Al4V microlattice structures with strut thickness nearing the single-track width of the laser-based powder bed fusion (LPBF) system used. Besides providing new information on the mechanical properties and manufacturability of such thin-strut lattices, this paper also reports on the in situ deformation imaging of microlattice structures with six unit cells in every direction. LPBF lattices are of interest for medical implants due to the possibility of creating structures with an elastic modulus close to that of the bones and small pore sizes that allow effective osseointegration. In this work, four different cubes were produced using laser powder bed fusion and subsequently analyzed using microCT, compression testing, and one selected lattice was subjected to in situ microCT imaging during compression. The in situ imaging was performed at four steps during yielding. The results indicate that mechanical performance (elastic modulus and strength) correlate well with actual density and that this performance is remarkably good despite the high roughness and irregularity of the struts at this scale. In situ yielding is visually illustrated.

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Milayzaki, Tomoyuki, Takayuki Matsumoto, and Takashi Yamamoto. "Effect of Visco-Elastic Property on Friction Characteristics of Paper-Based Friction Materials for Oil Immersed Clutches." Journal of Tribology 120, no. 2 (April 1, 1998): 393–98. http://dx.doi.org/10.1115/1.2834439.

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The friction characteristic of paper-based friction materials is one of the most important factors that influence the shifting performance of oil immersed clutches in automobile automatic transmissions. Visco-elasticity and porosity of the material are considered to be important properties that may control the friction characteristics of the material. In this study, the relationship between the friction characteristics and the visco-elasticity of a paper-based friction material is discussed. In order to vary the visco-elasticity while retaining the ingredients almost constant in a paper-based friction material, the formulation of the sample materials required changing the compression rate during the clutch plate bonding process and changing the volume percentage of resin. The properties of the sample materials such as porosity (pore diameter, pore diameter distribution, porosity percentage), and visco-elastic deformation in the compressive and the shearing directions, etc. were measured. In order to clarify the relationship between the friction and visco-elasticity of friction material, friction characteristics were measured. Friction characteristics of the sample materials were evaluated by a breaking-away test and continuous slip tests with a newly designed friction testing machine. From the experimental results, which showed that the lower the longitudinal modulus of the friction material, the higher the friction coefficient, it was found that friction characteristics of oil immersed paper-based friction materials are influenced by the visco-elasticity.

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Zeng, Kun, Guiyun Tian, Bin Gao, Jia Liu, Yi Liu, and Qianhang Liu. "Comparison of Repeatability and Stability of Residual Magnetic Field for Stress Characterization in Elastic and Plastic Ranges of Silicon Steels." Sensors 22, no. 8 (April 15, 2022): 3052. http://dx.doi.org/10.3390/s22083052.

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Deep insights into microstructures and domain wall behaviors in the evaluation of different material statuses under elastic and plastic stress ranges have essential implications for magnetic sensing and nondestructive testing and evaluation (NDT&E). This paper investigates the repeatability and stability of residual magnetic field (RMF) signals using a magneto-optical Kerr effect microscope for the stress characterization of silicon steel sheets beyond their elastic limit. Real-time domain motion is used for RMF characterization, while both the repeatability under plastic ranges after the cyclic stress rounds and stability during relaxation time are studied in detail. The distinction between elastic and plastic materials is discussed in terms of their spatio-temporal properties for further residual stress measurement since both ranges are mixed. During the relaxation time, the RMF of the plastic material shows a two-stage change with apparent recovery, which is contrasted with the one-stage change in the elastic material. Results show that the grain boundary affects the temporal recovery of the RMF. These findings concerning the spatio-temporal properties of different RMFs in plastic and elastic materials can be applied to the design and development of magnetic NDT&E for (residual) stress measurement and material status estimation.

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Kwon, Junbeom, Jaeyoung Choi, Hoon Huh, and Jungju Lee. "Evaluation of the effect of the strain rate on the tensile properties of carbon–epoxy composite laminates." Journal of Composite Materials 51, no. 22 (December 12, 2016): 3197–210. http://dx.doi.org/10.1177/0021998316683439.

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This paper is concerned with evaluation and prediction of the tensile properties of carbon fiber-reinforced plastics laminates considering the strain rate effect at intermediate strain rates. Uniaxial tensile tests of carbon fiber-reinforced plastics laminates were conducted at various strain rates ranging from 0.001 s–1 to 100 s–1 using Instron 8801 and a high speed material testing machine to measure the variation of the elastic modulus and the ultimate tensile strength. Tensile test specimens were designed based on the ASTM standards and stacked unidirectionally such as [0°], [90°] and [45°] to predict the elastic modulus of carbon fiber-reinforced plastics laminates with various stacking sequences. The axial strain was measured by the digital image correlation method using a high speed camera and ARAMIS software to enhance the accuracy of the strain measurement. A prediction model of the elastic modulus of carbon fiber-reinforced plastics laminates is newly proposed in consideration of the laminate theory and the tensile properties of unidirectional carbon fiber-reinforced plastics laminates. The prediction model was utilized to predict the tensile properties of [0°/90°]s laminates, [±45°]s laminates, and [0°/±45/90°]T laminates for validation of the model. The elastic moduli predicted were compared with the static and dynamic tensile test results to confirm the accuracy of the prediction model.

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Clay, Stephen B., and Philip M. Knoth. "Experimental results of quasi-static testing for calibration and validation of composite progressive damage analysis methods." Journal of Composite Materials 51, no. 10 (July 15, 2016): 1333–53. http://dx.doi.org/10.1177/0021998316658539.

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The Air Force Research Laboratory directed a research program to evaluate nine different composite progressive damage analysis methods under both quasi-static and fatigue loading. This paper describes the coupon tests that were performed at the Air Force Research Laboratory for calibration and validation of the methods under quasi-static conditions. The basic elastic and failure properties of unidirectional IM7/977-3 graphite/epoxy were first determined in order to properly calibrate the models. Validation tests were then performed on unnotched and open-hole coupons with three different laminate stacking sequences under both tension and compression loading conditions. This paper summarizes these experimental results and provides X-ray computed tomography images at subcritical load levels.

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Kumar, Nitesh, Ananda Babu, Alok Kumar Das, and Ashish Kumar Srivastava. "Effective Evaluation of Elastic Properties of a Graphene and Ceramics Reinforced Epoxy Composite under a Thermal Environment Using the Impact Hammer Vibration Technique." Coatings 12, no. 9 (September 12, 2022): 1325. http://dx.doi.org/10.3390/coatings12091325.

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This paper presents an evaluation of the mechanical properties of nanocomposites when a lower concentration of nanoparticles graphene and ceramics are mixed with epoxy to determine the damping and stability characteristics of hybrid epoxy, using vibration techniques to extract accurate results. The effectiveness of the Impact hammer vibration technique is validated with mechanical testing such as three-point bending in terms of Young’s modulus of the nanocomposite. The graphene nanocomposite carries nanoparticle 1 wt.% of epoxy, while the ceramic nanocomposite carries 3 wt.% of epoxy. It is observed that the reduction in frequency under a thermal environment is significantly less for graphene and ceramic reinforced hybrid nanocomposites, whereas the reduction in pure epoxy under a thermal environment is high. Thus, the results show that the addition of nanoparticles to composites shows improvement in the mechanical and thermal stability of elastic properties. The elastic properties obtained from the vibrational analysis are more consistent and economical than the three-point bending test for the evaluation of hybrid nanocomposites.

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Guo, Wei, Meng Yang, Hui Li, and Jing Wu Zhang. "Performance of Precipitates in the Stress Aging Treatment of 7075 Al Alloy." Advanced Materials Research 756-759 (September 2013): 93–96. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.93.

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The effect of elastic stress on the precipitation process of 7075 Al alloy aged at 438 K for 1 hour has been investigated in this paper. The mechanical properties have been measured by hardness testing and scanning electron microscopy (SEM) and the microstructures have been characterized by optical microscopy (OM), together with transmission electron microscopy (TEM). Results indicate that the microhardness can reach 180 HV after a 25 MPa elastic tensile stress aging treatment, much higher than the stress-free ones'. The fracture is more brittle and the formation of the precipitates is promoted in the case of the stress-aged specimen. Our study provides a new process to bring down the energy consumption.

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Logoń, Dominik, Krzysztof Schabowicz, and Krzysztof Wróblewski. "Assessment of the Mechanical Properties of ESD Pseudoplastic Resins for Joints in Working Elements of Concrete Structures." Materials 13, no. 11 (May 26, 2020): 2426. http://dx.doi.org/10.3390/ma13112426.

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Concrete structure joints are filled in mainly in the course of sealing works ensuring protection against the influence of water. This paper presents the methodology of testing the mechanical properties of ESD pseudoplastic resins (E-elastic deformation, S-strengthening control, D-deflection control) recommended for concrete structure joint fillers. The existing standards and papers concerning quasi-brittle cement composites do not provide an adequate point of reference for the tested resins. The lack of a standardised testing method hampers the development of materials universally used in expansion joint fillers in reinforced concrete structures as well as the assessment of their properties and durability. An assessment of the obtained results by reference to the reference sample has been suggested in the article. A test stand and a method of assessing the mechanical properties results (including adhesion to concrete surface) of pseudoplastic resins in the axial tensile test have been presented.

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Amjadi, Mohammad, and Ali Fatemi. "Tensile Behavior of High-Density Polyethylene Including the Effects of Processing Technique, Thickness, Temperature, and Strain Rate." Polymers 12, no. 9 (August 19, 2020): 1857. http://dx.doi.org/10.3390/polym12091857.

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The primary goal of this study was to investigate the monotonic tensile behavior of high-density polyethylene (HDPE) in its virgin, regrind, and laminated forms. HDPE is the most commonly used polymer in many industries. A variety of tensile tests were performed using plate-type specimens made of rectangular plaques. Several factors can affect the tensile behavior such as thickness, processing technique, temperature, and strain rate. Testing temperatures were chosen at −40, 23 (room temperature, RT), 53, and 82 °C to investigate temperature effect. Tensile properties, including elastic modulus, yield strength, and ultimate tensile strength, were obtained for all conditions. Tensile properties significantly reduced by increasing temperature while elastic modulus and ultimate tensile strength linearly increased at higher strain rates. A significant effect of thickness on tensile properties was observed for injection molding specimens at 23 °C, but no thickness effect was observed for compression molded specimens at either 23 or 82 °C. The aforementioned effects and discussion of their influence on tensile properties are presented in this paper. Polynomial relations for tensile properties, including elastic modulus, yield strength, and ultimate tensile strength, were developed as functions of temperature and strain rate. Such relations can be used to estimate tensile properties of HDPE as a function of temperature and/or strain rate for application in designing parts with this material.

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Journal articles on the topic 'Paper Elastic properties Testing'

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