Papers by Keyword: Numerical Analysis

Abstract: Two-Dimensional finite element analysis was used to investigate the performance of seawall construction over weak subgrade soil using artificial base layer material consisted of cemented sand cushion comprising geosynthetics materials. Two types of base layer materials pure sand and cemented sand comprising husk rich ash and two types of geosynthetics materials geogrid and geotextile were used. Constitutive models were used to represent different materials in numerical analysis. The competence of two-dimensional numerical analysis was compared with experimental results. Numerical results showed a superior harmony with the experimental results. Finite element analysis model proved to be a great tool to determine the parameters that are difficult to measure in laboratory experiments. In addition, finite element analysis has the benefit of cost and time saving when compared to experimental investigation work. Numerical results showed strain induced in geosynthetics eliminated beyond a distance approximately equal six times of footing width.

Abstract: Explicit FEM model ANSYS-DYNA is applied to simulate dynamic response and damage morphology of RC beam under blast loading. The dynamic response and damage morphology of reinforced concrete beam is analyzed under the different burst points, different explosive locations with the same proportion distance. The results show that: Under the same blast loading, the extent of damage of RC beam under complex boundary was lighter than the simply supported beam because of the stiffness contribution of slab and column. Acceleration at the half span point of the beam was 1/3 of simply supported beam, and the explosion shock attenuation was obvious.

Abstract: In order to exactly master effect of uranium material’s heat power on safety and reliability of nuclear weapon, weapon-grade uranium(WgU) and depleted uranium(DU) were regarded as research object in this paper. According to their component, decay heat power of WgU and DU per kilogram was calculated through dynamic decay cascade and decay law of uranium. Decay heat power of WgU and DU was respectively 1.8152 and 0.4075 milliwatt per kilogram. Main nuclide influencing on decay heat power of WgU and DU is uranium-234(U-234).

Abstract: Accurate descripting the temperature distribution of stator bars for the genaraors with big capacity is necessary. The stator bar of one 600MW generator was simulated for getting the temperature distribution. Several methods of dealing with the insulations were compared. How the heat conduction performance of insulations is good for the heat transfer of stator bars was discussed.

Abstract: Understanding vehicle occupant responses during real-world rear collision accidents is very important in the development of appropriate safety technologies for neck injury lessening. In this study, numerical analysis of vehicle occupant responses during rear impact were conducted by using a human multi-body model, a seat finite element model and crash accelerations obtained from real-world accidents. The human multi-body model was developed based on the body characteristics of a typical Japanese male, including the outer body geometry, inertial properties of body segments and passive joint characteristics. The seat finite element model was extracted from a detailed car finite element model. A small modification was done to the seat model to deal with the rear impact simulations. The crash accelerations were obtained from the drive recorder database of rear collision accidents occurred in Japan. Several crash accelerations were selected and used as input conditions during the rear impact simulations. Kinematic responses of the occupants during the accidents can be reasonably predicted by the simulations. Furthermore, different level of accelerations leads to different kinematics responses that may cause variation in injury occurrence and injury severity.

Abstract: Solid-state welding is useful to join dissimilar metal couples, in particular, with a large difference in physical and mechanical properties. However, conventional solid-state welding methods such as diffusion welding and roll bonding are not necessarily applicable to all metal combinations. In addition, they are time-consuming. In the present study, various dissimilar metal joints (e.g. Al/Fe, Al/Cu, Al/Ni, A2024/A5052, A6022/steel, A6022/Plated steel, A2024/AZ80) were fabricated by using several types of high-speed solid-state welding methods; friction stir spot welding, advanced stud welding and impact welding. The strength and characteristic interfacial morphology of the joints were investigated, and each joining mechanism is discussed. In particular, for the impact welding, both experimental and numerical analyses were performed. Two metal sheets were obliquely collided at a very high speed and joined by magnetic pressure or explosive force. Smoothed Particle Hydrodynamics (SPH) method was used to simulate the impact welding process. The emission of metal jet and the evolution of characteristic wavy interface at the joint interface could be clearly visualized. The effects of collision angle, collision velocity and difference in density of the metals on the wave morphology were revealed.

Abstract: By FEA method, the bending of the copper alloy thin-plates by continuous laser forming (CLF) and pulse laser forming (PLF) was studied. Based on the analysis of dynamic change and steady distribution for the fields of temperature, stress/strain and displacement, the forming mechanism and rule of copper alloy by different laser modes were revealed. The whole deformation of PLF was the additive effect of all impulse action, while CLF mainly was the result of thermal stress. To get the same deformation, laser pulse energy is about 6 times of the continuous laser，CLF is suitable for larger deformation demands, and PLF is more seemly for micro-forming.

Abstract: Thermal accumulation in micro droplet deposition manufacturing (MDDM) has a significant influence on geometric profile and microstructure of the fabricated metal micro-parts. In this paper, thermal behavior of a new aluminum droplet on the deposit surface was investigated using one-dimensional heat transfer model. Then several thin-walled aluminum cubic pipes were fabricated by MDDM to verify the numerical analysis result. The result shows that the thermal accumulation would increase gradually with the increase of the deposit height. It associated with thermal input and output on the top surface of the deposit, which could be controlled or eliminated by optimizing processing parameters such as deposition frequency.

Abstract: This paper discusses the process of calculating the lay-up configuration and structural stiffness of carbon fiber composite bike frame. First, a program is written in ANSYS macro language to calculate the lay-up configuration of the composite. The user only has to input the geometry, fiber orientation and sequence of individual layer, according to the original shop drawing. The program will then calculate the lay-up configuration of all the details for the whole structure automatically, and create the finite element model for ANSYS. The stiffness is then analyzed according to the product specification, and also compared with test result to evaluate the validation of the model. This automated process can accelerate the development time frame, and also work as the basis of parametric model for future design optimization.

Abstract: This paper uses EVA investment objective function and benefits to establish the risk assessment model of enterprise investment and financing combination, and expounds the specific processes of computer EVA investment and financing risk management and designs the elimination matrix algorithm. In order to validate the validity and reliability of risk assessment model designed in this paper, the third part has designed numerical simulation of MATLAB, and an enterprise's 2011-2013 financial statements is took as an example to assess enterprise investment and financing risk. It can find that through calculation, the calculation error can achieve good convergence effects in 20s, and obtain the MATLAB GUI visualization window of enterprise investment and financing EVA accounting. It can identify enterprise year EVA profit value by using visualization window, which provides theoretical reference for enterprises investment and financing risk management.