Papers by Keyword: Elastic Energy

Abstract: The objective of this research work is to analyze the behavior between fiberglass laminate under tensile tests, assembled under different humidity conditions. For which specimens were designed under the regime of the international standard ASTM D3039; which took an assembly process within a controlled environment; the design variables used were relative humidity and curing time. Subsequently, the traction-displacement behavior was checked under a uniaxial force, obtaining the maximum take-off force. In addition, Simpson numerical integration was applied to calculate elastic energy. Obtaining that the relative humidity and the days of curing influence the chemical and mechanical properties of the material. Se shows that the percentage of humidity recommended for assembling laminates in GRP is 66% since it has greater elastic energy and take-off force. Finally, it is concluded that to have a high resistance in the material at least 7 days of curing of the epoxy resin must be applied.

Abstract: Now a days, extensive research has been attracted by the α + β based Ti alloys in biomedical applications due to their low elastic modulus and high strength properties. In order to explore the performance of Ti6AlxMo based alloys, Ti6Al with different amount of Mo-based samples were fabricated by powder metallurgy technique. The mechanical properties of the samples such as elastic energy, total energy and elastic recovery were studied through nanoindentation tests. Designed alloys exhibit elastic recovery values in the range of 25.4% - 33.7% which is higher than commonly used biomaterial such as CP Ti therefore it has good impact resistance properties. Ti6Al15Mo alloy with dominant β phase microstructure shows a high elastic energy as well as elastic recovery values which makes it more advantageous than CP Ti for load bearing implant applications.

Abstract: Five engineered cementitious composite mixtures were adopted in this study with five different contents of 0, 0.5, 1.0, 1.5 and 2.0% of untreated low cost PVA fiber. Four different test specimens were prepared from the five mixtures to conduct several tests. Abrasion tests were conducted using 300 mm discs for six time steps each of 12 hours, while 100 mm cubes were used to evaluate the compressive strength. Cylinders with 100 mm diameter and 200 mm depth were adopted for splitting tensile strength, while four-point bending tests were conducted using small concrete beams with a span of 210 mm. The modulus of rupture was calculated from the tested beams, while the stiffness and elastic energy were calculated based on the load and deflection records of the beams. The tests showed that compressive strength did not affected noticeably by fiber inclusion, while all other mechanical quantities in addition to abrasion resistance exhibited significant improvement due to PVA fiber effect. The stiffness, splitting tensile strength, modulus of rupture and elastic energy exhibited maximum developments of 45, 134, 287 and 1181%, respectively, due fiber addition to the mixture. Quadratic formulas were found to be very accurate to correlate the relationship between abrasion depth in millimeters and each of splitting tensile strength, modulus of rupture and elastic energy, where R² values of these relations were between 96.7 and 99.5%.

Abstract: There is the opinion, imprinted by tradition, that only bronze alloyed with tin may be used to build bells, musical instruments or sound transmitters, without the need to bring a scientific explanation. Starting from the physical theory and experimental determination that sound travels only through bodies with elastic proprieties, a study over acoustic white cast iron was proposed. After convincing experiments, it results that white cast irons have good properties for producing and transmitting sound waves. The measurements focused two fundamental aspects, the elastic energy available for producing and transmitting sounds and amortization, resulting that white cast irons can substitute with success bronze with tin or even better properties.

Abstract: According to the gas dynamic theory, this paper deduces the approximate calculation formula on elastic energy of a tons of coal through theory analysis, and then gets the quantitative calculation method between incident overpressure and reflected overpressure of the coal and gas outburst shock wave. The calculation formula in this paper is in line with the measured values, and so its validity has been verified. The analysis result shows that the effect of the elastic energy during the process of coal and gas outburst should be considered when the depth of the coal seam is great and the coal’s modulus of elasticity is small.

Abstract: Using our local equilibrium model of the martensitic transformation [ the elastic energy contributions, as the function of martensite volume fraction, ξ, in the phase transformation of single crystalline Cu-11.5wt%Al-5.0wt%Ni shape memory alloy were calculated from our measurements published earlier [. The derivative of the elastic energy δE/δξ=e (E is the total elastic energy stored/released during the austenite to martensite (AM) as well as MA transformation) could be calculated only irrespectively of the ST₀ term (T₀ is the equilibrium transformation temperature and S is the entropy change of phase transformation). But, since ST₀ is independent of ξ, the functions obtained reflect the ξ dependence of e as well as E quantities. From the DSC curves measured at zero uniaxial stress (σ = 0) [, the ξ-T hysteric loop was constructed. Then the e (ξ) curves at fix σ as well as fix T were calculated. The E values obtained from the integral of e (ξ), fit well to the E(σ) as well as E(T) curves calculated from the strain-temperature and stress-temperature curves measured in [.

Abstract: The properties of roof play an important role in the formation and occurrence of rock burst. FLAC 3D is used to simulate the process of excavation and collapse in face advance with difference roof properties based on the elastic theory and field data of “7.16 Accident of rock burst” at Chengshan coal mine. As a result, the energy distribution law on the monitoring plan under different roof properties is given with Fish function. According to the analysis above, hard roof is a crucial reason to cause the accident.

Abstract: This study focuses on the entire shape of the  twin-precipitate in two phase stainless steel, Fe-25Cr-6Ni in terms of the interphase and elastic strain energies generated between the precipitate and matrix. An investigation of this precipitation is important not only in terms of microstructure control but also for improving the mechanical properties of materials. Firstly, the three-dimensional near-coincidence site lattice (3D-NCS) model, which is based on the atomic matching model, is applied for estimating the preferred habit planes by evaluating the result of geometrical atomic matching. Subsequently, the precipitate shape is determined from candidates of the preferred habit plane produced by the 3D-NCS model, and the elastic strain surrounding and within the precipitate is investigated by FEM analysis, which can calculate the anisotropic elastic strain depending on the shape of the precipitate. The results are compared with observed precipitate by TEM.

Abstract: The effect of hydrostatic pressure mechanically applied to hydride on the equilibrium hydrogen gas pressure and temperature have been examined theoretically. From free energy calculations where elastic energy is taken into account, equilibrium gas pressure and temperature increases and decreases with increasing applied compressive stress, respectively. In the case of magnesium hydride, equilibrium temperature decreases to 63 °C at the hydrogen gas pressure being 1 atom when volume expansion at hydriding is perfectly suppressed by an external compressive stress. The temperature is remarkably lower than that obtained by alloying various elements.

Abstract: Ankle Foot Orthosis (A.F.O) should endure the uncountable repeating impact and fatigue loadings due to the gait characteristics. This study investigated the impact deflection and relationship between the absorbed energy and the residual strength rate using the cross ply GFRP (glass/epoxy) and the woven AFRP (aramid/epoxy) for the leaf spring in A.F.O. In conclusion, the equation was suggested to evaluate the absorbed energy and the residual strength rate by the different impact velocities. When the cross ply GFRP and the woven AFRP was selected for the leaf spring in A.F.O, it was reasonable to use the cross ply GFRP for the parts subject to the large impact and the woven AFRP for the parts to require the high elastic energy such as the large deformation.