Advanced Materials Research Vols. 291-294

Abstract: The expansion chamber mufflers compounding with the perforated panels are commonly used in the suppression of intermittent exhaust noise (IEN) generated by the exhaust air from the cylinder and ducts of pneumatic devices. The flow resistance and noise reduction performances of IEN are both important. A simplified aerodynamic model is presented to study the flow characteristics in the pneumatic cylinder and chambers of the muffler with perforated panels. The relationship between pressure and mass flow rate is established in the transient exhaust process. Validation experiments measuring the cylinder pressure and exhaust noise of the pneumatic friction clutch and brake (PFC/B) exhaust system installed a three-level perforated panel muffler which can be separated show that the calculated results are very close to that of the actual exhaust process.

Abstract: Based on the theory of elasticity and taken the casing-cement sheath as a totally contacted composite cylinder subjected to arbitrarily distributed loading on inner and outer surfaces, an analytical solution in Fourier serial form was obtained for stresses and displacements. A computer program was developed to evaluate the stress and displacement in the combined cylinder. The results are in good agreement with those from the finite element method (FEM). With these solutions we can investigate the interaction between casing and the cement sheath. This is of importance in improving the design of casing.

Abstract: Based on the analytical solution for the stress field around an inclined borehole in an anisotropic medium, a computer program was developed and a serial parametric study was conducted. The effects of parameters such as degree of anisotropy, borehole inclination, bedding plane inclination and in-situ stress conditions on the stress distribution around a borehole were evaluated. The results showed that medium anisotropy has little effect on borehole fracture analysis at low borehole inclinations, but its influence becomes significant for highly inclined boreholes. As the degree of anisotropy varies the maximum shear stress changes remarkably. This indicates that the degree of anisotropy plays a role in the collapse failure of a borehole. The information generated in these studies can be used in predicting the fracture or collapse-initiating pressures.

Abstract: In order to guarantee the safe operation of train and improve the operation efficiency, a kind of failure-safety control strategy of system is proposed based on the dual-redundant control mechanism. The paper analyzes the function requirement of train automatic speed control, researches on the design principles and methods of the architecture design of the dual-redundant control system which is based on the tolerance theory, analyzes the control strategy of the system running state translation, uses Markov model to analyze the system reliability and safety. Finally, a series of simulation analysis are performed, and the results show that the system has good reliability.

Abstract: This paper is based on the gray model reliability theory that established system information incomplete state reliability comprehensive analysis method. Through the gray model reliability that can complete system, forecast, assessment information processing methods, mechanical system for internal and external rules, foresee the future development of the mechanical system and realize speed selection evaluation of mechanical products.

Abstract: Based on failure mode analysis of the cermet cladding part, the last layer failure assumption is adopted and the method to establish reliability model of the cladding part based on the failure tree series is proposed. Theoretical and example investigations are carried out. The failure tree series for the failure process of the cermet cladding part under the mechanical impact are established.

Abstract: Based on the mechanism, influencing factors and their fuzziness of reinforced concrete (RC) cracking caused by corrosion of steel bars, fuzzy reliability of RC durability failure due to corrosion expansion of steel bars is analyzed adopting the mathematic model of fuzzy probability. The method having the advantages of explicit concept, convenient calculation and stable results which is proved by the examples accords with the actual situation and can be applied to the engineering practice.

Abstract: Reliability of equipment has long been considered as an important quality characteristic. But the reliability assessment of multi-parameter system still remains a problem. Based on the multi-parameter degradation process of a certain diesel engine, the article proposes a reliability assessing method for multi-parameter degradation system. The method uses SVDD to convert multi-parameter into one single degradation measure which reveals the overall system degradation. Using degradation measure distribution, a reliability assessment model is built. Through experiments on vehicle, the method shows the degradation regular of vehicle diesel engine, builds the reliability curve, provides evidences for equipment maintenance.

Abstract: In view of the questions of high-speed aircraft withstanding complicated vibration environment, their vibration durability could not being plenary examined by existing vibration test technology, a vibration test technique integrating piezoelectric element, vibrating table, exciter is proposed. The vibration environment dimension of high-speed aircraft and its influence to the failures of high-speed aircraft are analysed. Based on the research on the material and actuation dimension of the piezoelectric element, the feasibility of piezoelectric element used as the distributed excitation source in vibration test is analysed. Last, a test demonstration system is constituted and a serials of test items are carried out. The rationality and the extensive engineering application potential of this technique are verified by the test results.

Abstract: An investigation has been conducted into the time-dependent chemical degradation of rubber linings produced from Isobutylene-Isoprene Rubber (IIR). These linings are used for the corrosion protection of steel reservoirs and pipelines within various chemical environments. High resolution core level and valence band X-Ray photoelectron spectra XPS of the degraded copolymer IIR have been obtained with the low-current, low-energy electron beam flood gun charge compensation. The components of region C(1s) and O(1s) have been distinguish in the individual peaks during testing. The Full Width of Half Maximum (FWHM) of curve-fitted components has appeared below 1.6 eV. All results of the C(1s) values have taken the stability of the carbon polymer chain, including the vulcanization agent, into consideration. Direct correspondence for carbon-oxygen systems between the O(2s) at ~27.5 to 24.1 eV and O(1s) at ~535.4 to 530.6 eV binding energies has been described. C(1s) loss peak has appeared at ~21 eV from the principal and it’s loss splitting for C-C and C-H bounds has been confirmed.