Applied Mechanics and Materials Vols. 444-445

Abstract: This paper presents a comprehensive review of computational Intelligence (CI) technology applied in structural damage identification, clarifies the basic principles of computational intelligence techniques, as well as the applicable difficulties that exist in the field of structural damage identification (SDI) from 6 aspects: fuzzy theory, evidence theory, rough set theory, artificial neural networks, support vector machines and evolutionary computation, and then discussed the applicable prospects of computational Intelligence in SDI. It points out that the reasonable cross-fusion of a variety of CI method to specific research object is a necessary means for SDI research. For economy and practicality considerations, CI is suitable for highly integrated complex structural damage identification.

Abstract: To investigate the mechanism of TUSOG(Transverse Uniform Singlet Oxygen Generator), a two-phase, chemistry reactive flows model is established to describe the physical and chemical performances of Cl₂/He mixed gases which transversely travels through a falling BHP(KOH,H₂O₂,H₂O) droplets field, and the relevant numerical simulation is carried out. In the gas-phase model equations, the mass source term is determined by drop-absorbed chlorine and released singlet oxygen due to chemical reaction between drops and chlorine. An assumption is made that the BHP drops have equal sizes and fall vertically in equal speeds. The set of gas-phase control equations is solved by SIMPLEC scheme. The computational results agree well with the test results provided by relevant reference. It is found, that chlorine utility and singlet oxygen yield decreases with increasement of gas inflow speed, and increases with increasement of the speeds of falling drops, and the absorption of chlorine mainly takes place in the upstream reactive region.

Abstract: Widespread Fatigue Damage (WFD) issue is a major threat to the structural integrity of the aging aircrafts, So WFD assessment is a key measurement and necessary task to ensure the continuing airworthiness. A methodology using probabilistic framework to assess WFD was developed. The major feature of this method is that a stochastic process which is introduced to crack initiation and crack growth as well as yield stress and fracture toughness. Stress Intensity Factor (SIF) was incrementally calculated using Finite Element Method (FEM). Numerical studies were performed for panels with five holes using Monte Carlo Simulation (MCS). The WFD Average Behavior, include inspection, monitoring and repair period, was presented, and the convergence of the MCS was also discussed. The effectiveness of this methodology was verified by comparing the experimental data. This approach simulated and evaluated the WFD behavior and got the relative statistic data, which provided a practical engineering method for WFD evaluation.

Abstract: An improved element free Galerkin method coupled the precise time-step integration method in the time domain is proposed for solving transient heat conduction problem with spatially varying conductivity in the paper. Firstly the nodal influence domain of element free Galerkin methods is extended to arbitrary convex polygon rather than rectangle and circle. When the dimensionless size of the nodal influence domain is 1.01, the shape function almost possesses interpolation property, thus essential boundary conditions can be implemented without any difficulties for the meshless method. Secondly, the precise time-step integration method is selected for the time discretization in order to improve the computational efficiency. Lastly, one numerical example is given to illustrate the highly accurate and efficient algorithm.

Abstract: Machinery, especially, lead electrolysis Non-ferrous Metallurgy industry needs higher and higher temperature accuracy in manufacturing equipments by accompanying the development of the science and technology. During the process of lead electrolysis manufacturing equipment, the anode plate vertical casting system is a producing device which aims to complete the casting of the anode plate. However, simple cool system and poor cool effect and lower production efficiency of the domestic anode plate manufacturing equipment are the common short comings which exist currently. Therefore, we designed in Solidworks based on a comprehensive analysis of the mechanical structure of the mold, and obtain the time of right temperature of moving mould in a stable state, thought to verify the rationality of the design of the equipment cooling system.

Abstract: Through a series of drainage analysis of plane strain compression tests on the Toyoura sand under different stress path, we found that the plastic shear strain and stress path of great relevance. But due to that a yield locus represents a specific yield level and usually do not related with stress paths, the hardening parameter of the parametric should also has nothing to do with the stress path. This article based on the analysis of the laboratory test results, put forward a stress path-independent plastic shear strain energy modified function as shear yield hardening parameters. Then based on the above type of energy state function proposed to build a sandy soil elasto-plastic constitutive model, and compared with corresponding numerical calculation results to make an effective verification.

Abstract: Application of Digital image correlation method (DIC) to measure the elastic modulus and Poisson ratio of rubber under compression is investigated in this paper. Surface images of the rubber surface subjected to various loading were captured using a CCD camera. DIC is subsequently used to obtain displacement field by correlating the images captured before and after deformation, and then the average compression strain is obtained by fitting the displacement using linear plane. The slope of each set of applied stress versus measured strain data is calculated by least-squares linear regression. The elastic modulus and Poisson ratio obtained from DIC, are compared to that determined from the dial gauge, which shows that they are in good accordance with existing data. Experimental results clearly show that DIC is suitable for accurate measurement the elastic modulus of rubber.

Abstract: The packing container is used in storage and transport of the high explosive (HE) material. The study concerns the safety of the packing container in fire environment. The spruce wood filled in the packing container can effectively resist heat transfer and protect HE material. The thermal analysis of the packing container in the pool fire environment is presented with the finite element method. When considering the water evaporation and the wood pyrolysis, the enthalpy curve of wood is presented in this study. Heat can be transferred from the fire to the packing container via convection and radiation. Thus, two thermal boundary conditions are applied to the thermal model of the packing container. The simulations show the inner temperature distributions of the packing container are significantly affected by the wood-column thickness. For the same time, the simulations show there is a slight difference in the char layer thickness between two thickness wood columns. The computed results show there are large temperature gradients in the interface of char and wood. This demonstrates the spruce wood is the excellent thermal resistance material.

Abstract: Along with the development of economy, a growing of large electronics workshop projects and the increasing of workshop area, the difficulties of evacuation design in engineering design is increasingly protruding. Due to large cubic construction and the complexity of building function, the evacuation problems in fire protection design is difficult to solve when using existing national specifications. By using the method of performance-based fire protection design in electronic workshop personnel evacuation design, and using computer simulation technology to demonstrate its security, we can find the solution to similar engineering problems.

Abstract: In this paper, an extended lattice gas model is proposed to simulate pedestrian flow on floor-stair interface by considering inner-side walking preference, turning behavior and different desired speeds. The effects of different injection rates for pedestrians from corridor on the mean velocity and occupancy are investigated, and the merging behavior, which happened on floor-stair interface, is analyzed. The simulation results show that the extended model can reproduce some essential features of pedestrian flow on stairs, such as transition of movement state at higher injection rate, merging behavior on floor-stair interface. The effects of two kind of typical structures of the floor-stair interface on pedestrian merging behavior are discussed, and merging process simulated by the model appears biased to that the corridor is connected opposite to the incoming stair.