Applied Mechanics and Materials Vol. 302

Abstract: The recovery resistance, energy dissipation, and other mechanical properties of cement materials are evaluated based on the Hertzian indentation method in this work. It is significant and efficient for engineering application. In results, the calculated energy dissipation of clinker is higher than that of limestone, which can partially be used to explain why the grinding of clinker consumes a lot of energy in cement industry. The recovery resistance for limestone under the peak load of 100N is almost higher than of clinker. However, in contrast to that of 200N, the recovery resistance for limestone is almost identical to that of clinker. It is indicated that the clinker exhibits better plasticity. and greater energy absorption capacity.

Abstract: An analysis based on Lagrange equations was presented for acoustic and vibration characteristics of finite cylindrical shell-circular plate underwater. The boundary conditions and coupling conditions between the shell and plate expressed using springs, the model of finite shell with circular plate was set up. Considering the elastic potential energy in springs and the work due to fluid loading, the vibro-acoustic equations of finite cylinder with circular plate under excitation were established by Lagrange equations. The influences of boundary conditions and coupling conditions to the acoustic and vibration characteristics were researched. The results show that . The results could be used to control the underwater vehicle’s vibration and acoustic radiation.

Abstract: As a result of the flexibility provided by the transformation elastodynamics, the impedance-matched condition exists for both S and P waves in perpendicularly incident cases in isotropic materials, thus the isotropic elastic wave beam bender can be designed. In this paper, we explore some characteristics of this bender and show that by assembling the bender units a solid elastic beam can be guided to an arbitrary path, which will provide convenience in engineering practices. Examples are conceived and validated by numerical simulations.

Abstract: Thermoelectric (TE) modules are a thermo-element device that can harness the heat and convert it into electrical energy. As an electrical generator system, TE has several advantages i.e not noisy, easy maintenance, relatively small, lightweight and environmentally friendly because it does not produce pollution. In this paper, the research about the performance of TE modules that used for electric generator has been done. TE modules utilize low temperature waste-heat from a solar cell that simulated with a combination of a bulb and a collector plate. TE modules which tested are single and double modules, in which for double modules, connectivity Thermal-Series was used. Parameters of performance such as output power generated are determined by measuring the temperatures difference and the voltages difference at the test module as well as using several equations. The results show that the distance of heat source and load applied will greatly affect the performance of thermoelectric generator (TEG) modules. The results showed that the number of modules and loading will greatly affect the performance of TEG modules. The use of heat pipes generate a far greater power 4-6 times on the single TE Module (0.84 mW) than without heat pipe (0.14 mW), and a double TE modules that uses heat pipe will became 4 times larger (1.48mW) than without heat pipe (0.37mW).

Abstract: For the transfer station which selects Platform Interchange as interchange mode, this article proposes the method of taking Upstream Platform as buffer container to ease passenger flow pressure of downstream platform through the analysis of the reason why the downstream platforms which have different interchange modes put up different platform pressure. To be easy to study and describe, this article creates a new concept of Pressure Contribution Rate which is to measure the balance state of passenger flow pressure and designs a procedure to select the optimal case. Finally, the article proves the feasibility of the method by taking Fuxingmen station as the example.

Abstract: Natural convection heat transfer from discrete heat sources to nanofluids is of great importance because of its application in the cooling of electronic components. The presence of the nanoparticles in the fluids increases appreciably the effective thermal conductivity of the fluid and consequently enhances the heat transfer characteristics. The present study is aimed to investigate numerically the natural convection heat transfer from discrete heat sources to nanofluids. The behavior of nanofluids was investigated numerically inside a heated cavity to gain insight into convective recirculation and flow processes induced by a nanofluid. A computational model was developed to analyze heat transfer performance of nanofluids inside a cavity taking into account the solid particle dispersion. The model was validated through the comparison with available experimental data. The results showed good agreement. The influence of the solid volume fraction on the flow pattern and heat transfer inside the cavity was investigated. The results show that the intensity of the streamlines increases with the volume fraction. It is also indicated that higher velocities along the centerline of the enclosure are achieved as the volume of nanoparticles increases. The influence of the loading factor is more distinguished at the upper heaters and in particular at the highest heater. The heat transfer increases as the volume fraction of the nanoparticles increases from 2 to 10%.

Abstract: The article deals with the analysis of vertical vibrations of symmetric and asymmetric systems (possibility of application on vibration of vehicles and machinery units flexibly loaded machines). Vibration solution was performed by using numerical and experimental methods on a simple model of a vehicle. The complete solution of a space system has been made. The aim of the work was to build a mathematical model and its solution with use of FEM. The experimental solution was used to verify the numerical results and their verification.

Abstract: Based on the issue of the communication between two FlexRay nodes, this paper proposes a new design straight by illustrating the mechanism with respect to the way of performing it by both hardware and software means. The important part of the mechanism is demonstrated in detail. The experiments through two Electronic Control Units (ECUs) show that the design can realize the communication between two FlexRay nodes well.

Abstract: This work is aiming to investigate the dependence of the performance of a 3-D ITM reactor depends on the operating conditions and flow configuration. This work is a design problem, where the oxygen separation requirements of the ITM reactor are specified, and then the reactor is designed to meet them. The effect of subdividing the total reactor length into a number of parallel subunits rather than only one unit on the flow characteristics and membrane stability is studied. The results indicate that the average wall temperature is higher in the case of counter current flow than in the case of co-current flow; this is attributed to the effective heat transfer in the case of counter-current flow, and as a result, the average partial pressure driving force was found to be much lower in the case of counter current flow in order to get the same average flux for both flow configuration. The present results indicate that the use of parallel design instead of series design will result in shorten the channel length, reduce pressure drop through the system and will result in more stable operation of the membrane. Also, this design takes the benefit of high oxygen permeation flux at channel inlet which will reduce the total size of the reactor.

Abstract: In order to accurately predict the electromechanical coupling performance of bimorph piezoelectric cantilever structure. Based on Euler-Bernoulli beam assumption, the expression of output voltage response of the bimorph piezoelectric cantilever is written, the output voltage curve of unit acceleration excitation are obtained, the law of the output voltage influenced by the structure parameters of the cantilever beam length, width and thickness of the metal beam and the piezoelectric layer are analyzed, the results will play an important theoretical and engineering significance in the development of high efficient piezoelectric energy harvesting device.