Analysis And Modeling Of Impact Of Flood On A Dam Using Midas Software (A Case Study Of University Of Ilorin)

This project examined the computer aided modelling, analysis, and design, of a concrete gravity dam using MIDAS GTS software. A manual design based on stability analysis against sliding, overturning and shear friction of the dam due to a flood level of 7.6 m (same as the height of the dam) and a flood level of 10.5 m were included. Data used was collected from project planning unit (PPU) of the University of Ilorin for the analysis. Based on the manual design of the typical concrete gravity dam analysis carried out, the factors of safety against, Overturning, Sliding and Shear Friction Factor were 2.5, 2.3, and 47 (for the flood level of 7.6 m) and 1.5, 1.2, and 26 (for the flood level of 10.5 m) which are all greater than the allowable factors. . The principal stresses at the toe of the dam using manual and MIDAS software are 2.5 X 105 kN/????2 and 2.43 X 105 kN/????2 respectively and the shear stresses using manual and MIDAS software are 1.1 X 105 kN/????2 and 1.6 X 105 kN/????2 respectively (for the flood level at 7.6 m)

Finite Element Simulation of Cutting Forces in Turning Ti6Al4V Using DEFORM 3D

Titanium alloys are widely used in aerospace industry due to their excellent mechanical properties though they are classified as difficult to machine materials. As the experimental tests are costly and time demanding, metal cutting modeling provides an alternative way for better understanding of machining processes under different cutting conditions. In the present work, a finite element modeling software, DEFORM 3D has been used to simulate the machining of titanium alloy Ti6Al4V to predict the cutting forces. Experiments were conducted on a precision lathe machine using Ti6Al4V as workpiece material and TiAlN coated inserts as cutting tool. L9 orthogonal array based on design of experiments was used to evaluate the effect of process parameters such as cutting speed and feed with a constant depth of cut 0.25 mm and also the tool geometry such as rake angle on cutting force and temperature. These results were then used for estimation of heat transfer coefficient and shear friction factor constant, which are used as boundary conditions in the process of simulation. Upon simulations a relative error of maximum 9.07% was observed when compared with experimental results. A methodology was adopted to standardize these constants for a given process by taking average values of shear friction factor and heat transfer coefficient, which are used for further simulations within the range of parameters used during experimentation. A maximum error of 9.94% was observed when these simulation results are compared with that of experimental results.

Determination of a Dimensionless Equation for Shear Friction Factor in Cold Forging

In cold bulk forming processes, a constant shear friction model is widely used to apply friction. However, it is not easy to predict the shear friction factor since frictional behavior is highly nonlinear and is dependent upon a number of processing variables, such as the hardness of the material, lubricity, sliding velocity, surface contact conditions, and the environment, etc. This paper presents a dimensionless equation that predicts the shear friction factor at the counter punch interface mfd that was empirically determined by dimensional analysis, using the tip test results available in the literature as a function of selected process variables, such as the yield strength and initial specimen's radius of the deforming material, hardness, and surface roughness of the deforming material and the counter punch, viscosity of the lubricant, and deformation speed. To verify the determined equation, a new set of experiments were carried out for specimens made of AL7075-O. The prediction of the shear friction factor at the punch interface was also achieved by simply dividing the dimensionless equation by the x ratio defined by x = mfd/mfp, which is dependent on the hardening exponent of the deforming material based on previous studies. The predicted mfd and mfp were found to be reasonable owing to comparisons with the experimental data obtained for AL7075–O in this study. These results will be beneficial in scientifically assessing the effect of the processing parameters on the friction, individually and economically selecting the lubrication condition for cold bulk forming for practical applications.

Taguchi Method and Genetic Algorithm Neural Networks Analysis of Forging Process of Bicycle Chain Wheel

Recent years due to the rise of awareness of environmental protection and energy conservation are attention. Which is the most representative of the bike. Many processing factors must be controlled in the bicycle chain wheel. This study employed the rigid-plastic finite element (FE) DEFORMTM 3D software to investigate the plastic deformation behavior of an aluminum alloy workpiece as it is forged for bicycle chain wheels. Factors include the temperature of the forging billet, shear friction factor, temperature of die and punch speed control all parameters. Moreover, this study used the Taguchi method and Genetic algorithm neural networks to determine the most favorable optimization parameters. Finally, our results confirmed the suitability of the proposed design, which enabled a bicycle chain wheel die to achieve perfect forging during finite element testing.

Thread Forming of a Micro Screw for Storage Devices Using Finite Element Analysis

High precision micro screws have been widely required for the fastening parts of electronic storage devices. Teeth’s forming of the micro screw is generally utilized by a cold thread rolling process with a flat die. This process for micro sized parts has some difficulties such as the design of die shape, alignment between dies, and process managements. In this paper, it is focused on the effect of the alignment between dies and material, and process parameters in simulation. The investigated parameters are the friction coefficient and the relative position between stationary and moving dies using a numerical simulation. The simulations provide that the shear friction factor of 0.9 is proper for preventing slip between dies and raw material and the relative position of two dies has to be set to the half length of the pitch for maintaining the continuous thread profiles. The deformed shapes of the pitch part and the top part of threads can be demonstrated the feature of experimental result. The folding phenomenon appeared at the top part of threads, which seemed to be induced by a lack of the metal flow under micro sized deformation.

Finite Element Investigation of Friction Condition in a Backward Extrusion of Aluminum Alloy

Finite element simulations are being widely used to increase the efficiency and effectiveness of design of bulk metal forming processes. In such simulations, proper consideration of friction condition is important in obtaining reliable results. For this purpose, the shear friction factor is widely used for bulk deformation analyses. In the earlier work, it was found that a radial tip was formed on the extruded end of the workpiece and that the radial tip distance had a linear relationship with the forming load in the tip test. In order to characterize the global average shear friction factor, a linear relationship between the nondimensionalized radial tip distance and shear friction factor was numerically determined in this study for AL6061-O for various lubrication conditions. The global average friction condition at the bottom die interface was determined to be about 60 percent of the one at the punch in the backward extrusion under the present conditions.

Lubricant Modeling and Its Effect on Simulation of Material Forming

Solid cylinder upsetting is analyzed using three different approaches for frictional boundary condition modeling. These are (1) constant shear friction factor, (2) experimentally measured frictional stresses, and (3) analytical models accounting for lubricant entrapment and redistribution. All three approaches are implemented in the CFORM finite element code. The error between the three approaches and actual experimental measurements of the material deformation and interfacial pressures is investigated. It is shown that the constant shear friction factor is more accurate for solid film lubricants than for liquid lubricants. However, the calculations indicate that if accurate prediction of near net shape forming processes is to become a reality, improvements need to be made in the characterization of frictional boundary conditions. New theoretical developments applicable to arbitrary shapes and more accurate than the constant shear friction factor approach are needed.