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Tension Tests (tension + test)
Selected AbstractsMICROMECHANICS: SIMULATING THE ELASTIC BEHAVIOR OF ONION EPIDERMIS TISSUEJOURNAL OF TEXTURE STUDIES, Issue 1 2006JIMMY LOODTS ABSTRACT A generic modeling approach is introduced that allows for dynamical simulations of cellular biological tissue. It is derived from the discrete element approach in the sense that the tissue is discretized such that histological aspects like cell geometry and the cellular arrangement within the tissue can be fully incorporated into the model. This makes dynamical simulations of arbitrarily shaped cellular tissues feasible in an elegant and a robust way. The validity of this simulation technique is demonstrated by a case study on the unicellular epidermis layer of onion (Allium cepa). The parameters of a two-dimensional model are determined using published stress,strain data from a tension test on longitudinal strips. The model is then validated quantitatively against the data for transversal strips. [source] The conservation energy principle in description of stable and unstable states for aluminiumPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2009T. Wegner In the paper the physical model based on the energy conservation principle is proposed. On the basis of this principle the division of energy on volumetric and deviatory parts is presented. In this model a concept of energy division is recognised as important. Using the strain energy density function we can formulate criteria of the material equilibrium stability. Considerations are carried out for aluminium. All assumptions are based on uniaxial tension test supported by transverse deformation measurements. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Derivation of Recovery Kinetics From Stress Relaxation Tests,ADVANCED ENGINEERING MATERIALS, Issue 3 2010Sheila Bhaumik The recovery behavior of a commercial aluminum alloy 3103 was investigated by the means of two alternative experimental methods: stress relaxation (SR) and double tension tests (DT). In case of SR, the stress,time evolution after deformation was recorded, and for DT the yield stress after several recovery times were measured. The DT tests were further sub-divided into tests with and without external load during recovery. The results revealed that the recovery kinetics is clearly accelerated by the external stress during the SR. However, the difference between the DT and SR stresses is much larger. It is caused by continued dislocation glide after the deformation, which causes continued plastic elongation of the specimens. This is demonstrated quantitatively by appropriate evaluation models for both experiments. In contrast to DT, the SR evaluation accounts for the elastic SR due to plastic elongation, but the recovery parameters are the same ones as for DT. This makes it possible to replace DT by SR experiments, which are materially less laborious. [source] Effects of ultraviolet irradiation on the static and dynamic properties of neoprene rubbersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Hsoung-Wei Chou Abstract Rubbers deteriorate when they are exposed to ultraviolet irradiation for long periods of time. By conducting a series of hardness measurements and simple tension tests, the static properties of neoprene rubbers before and after exposure to various durations of ultraviolet irradiation were first measured. It is found that the Shore A hardness and tensile modulus of neoprene rubbers after exposure to ultraviolet irradiation are increased but their elongation at break, tensile strength, and energy to break are significantly decreased. On the basis of a complex spring model of a vibration system, the dynamic shear properties of neoprene rubbers before and after exposure to different durations of ultraviolet irradiation were then determined from the experimental results of dynamic transmissibility tests. It is also found that the storage modulus, loss modulus, and loss factor of neoprene rubbers are drastically affected by the duration of ultraviolet irradiation they experienced. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Combined Effect of Salt Water and High-Temperature Exposure on the Strength Retention of NextelÔ720 Fibers and NextelÔ720-Aluminosilicate CompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2006Triplicane A. Parthasarathy The relative contribution of fiber strength loss to reported degradation in the mechanical behavior of NextelÔ720-aluminosilicate composites after exposure to salt fog (ASTM B117) was explored. Single filament tension tests were performed on NextelÔ720 (3M, Inc., Minneapolis, MN) fibers after immersion in NaCl solutions followed by high-temperature exposure in air. The results were compared with the behavior of control specimens which received high-temperature exposure but were not immersed in NaCl solution. There was no degradation in fiber strengths for NaCl solutions below 1 wt%. However, significant degradation was observed at 5 wt% NaCl upon exposure to temperatures between 900° and 1150°C, while no degradation was observed upon an exposure to 1200°C. The relative contribution of fiber strength loss to composite degradation was estimated as nearly 50%, indicating that both fibers and matrix/interface degrade from exposure to salt water. X-ray diffraction and transmission electron microscopy of the exposed fibers and composites were conducted to help rationalize the observations. Microstructure of degraded fibers showed presence of Na at grain boundaries near the surface, without any evidence of a crystalline phase, indicating weakening from segregation or formation of an amorphous phase. The degraded composites showed that matrix and fiber/matrix interfaces had Na rich regions/phases. [source] Synergistic effect of chloride and sulfite ions on the atmospheric corrosion of bronzeMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 5 2006X. Cao Abstract The effect of chloride along with sulfite ions on the atmospheric corrosion of bronze was investigated by using periodic wet-dry tests, surface tension tests and electrochemical impedance measurements. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the corrosion products. Both the electrochemical impedance measurements and surface tension tests agreed well with the results of weight loss measurements. Synergistic effect of chloride and sulfite ions was observed during the whole process. In addition, we found that the attack of anions on the metal at the initial corrosion stage showed good agreement with their surface activity. However, as the corrosion proceeded, the interaction among the corrosion products induced by chloride and HSO3, accelerated the corrosion process. A scheme was given to explain the whole corrosion process. [source] Lateral compaction effects in braided structuresPOLYMER COMPOSITES, Issue 2 2003Robert A. Dasilva This paper addresses the phenomenology of strand interaction in biaxial non-embedded braided textile structures under uniaxial tension. The specific interest in the development of new braided textile structures is a result of the shortcomings of current rope, belt, and cable performance under large strain controlled conditions. However, this work also holds particular significance in the area of textile composite preforms. In composites forming, the lateral strand compaction mechanism, which drives braid behavior under tension, may be applied to woven fabrics for predicting wrinkling during forming processes. Additionally, manufacturing models produced in this study may be used to predict shape and size limitations of braided composite preforms. In this paper, a generalized model is developed for these structures with the intent of characterizing and predicting mechanical behavior. The methodology consists of a modular framework, which includes the prediction of manufacturing parameters. Lateral strand compaction tests were performed to generate constitutive material curves for use in analytical geometric models. Model predictions correlate well with data generated from braid uniaxial tension tests. Results suggest that lateral strand strain drives braid tensile behavior. [source] Modelling of viscoelastic material behaviour close to the glass transition temperaturePROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2009Michael Johlitz In this contribution we investigate the mechanical behaviour of polyurethane over a range of different but constant temperatures from the glass to the viscoelastic state. Therefore uniaxial tension tests are performed on dogbone specimens under different isothermal conditions. In this manner an experimental data set is provided. As a theoretical basis we present the well known thermomechanically coupled one dimensional linear viscoelastic material model which is able to display the experimentally observed material behaviour. For this we adopt temperature dependent relaxation times. The introduced model parameters are identified via a standard parameter identification tool. Finally, the experimental results are compared with the ones of simulations of the identified model parameters. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||