Modelling and FE Simulation of HVC Using Multi Objective Response Surface Optimization Techniques

The purpose of an automotive chassis is to maintain the shape of the vehicle and bear the various loads that are applied to the vehicle. The structure typically accounts for a large portion of the development and production costs of the new vehicle program, and the designer has many different structural concepts available. Choosing the best is important to ensure acceptable structural performance under other design constraints, such as cost, volume and method of production, product application, and more. The material selection for chassis depends upon various factors like lightness, economy, safety, recyclability, and circulation of life. The current study aims to perform optimization of the design of a heavy vehicle chassis using central composite design & optimal space fill design scheme (s) with the material tested is Al6092/SiC/17.5p MMC. Different design points are generated using design of experiments. The equivalent stress, deformation and mass are evaluated for each design points. The CAD modelling and FE simulation of heavy motor vehicle chassis is conducted using ANSYS software. From the optimization conducted on chassis design, response surface plots of equivalent stress, deformation and mass are generated which enabled to determine the range of dimensions for which these parameters are maximum or minimum. The use of Discontinuously Reinforced Aluminium-Matrix Composites Al6092/SiC/17.5p MMC aided to reduce weight of chassis by 66.25% and 66.68% by using CCD and Optimal space fill design scheme respectively, without much reduction in strength of chassis.

Evaluation of Damage Limit State for RC Frame Based on FE Modeling

Many damage limit states have been defined to characterize the extent of damages occurred in RC frame. Some of the damage limit states are defined by models that relate the limit states with the control points. Both control points and the limit state are expressed in term of response quantities. This research aims to evaluate the validity of such models by identifying the defined damage limit state with the corresponding damage based on FE modeling. The FE modeling provides a direct link between the damage and the response quantities. This link can be exploited as a basis for the evaluation. Based on the evaluation, this study proposed modified damage limit states. The response quantities with its corresponding progressive damage from FE simulation will also be used to inspect whether damage that can be expected to occur in the model structure is within the range estimated by the code based approach (CBA) damage limit state. Finally, fragility curves are constructed to assess the probability of the expected damage in the model structure under Design Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) scenarios. Utilizing the proposed damage limit states, the most probable damage in the structure falls in the category of slight if an earthquake at a level of DBE or MCE strikes the structure. However, at MCE level the probability of moderate damage attains 35%, or an increase by 23% compared to the DBE level.

Inverse Approach of Parameter Optimization for Nonlinear Meta-Model Using Finite Element Simulation

Accurate and efficient estimation and prediction of the nonlinear behavior of materials during plastic working is a major issue in academic and industrial settings. Studies on property meta-models are being conducted to estimate and predict plastic working results. However, accurately representing strong nonlinear properties using power-law and exponential models, which are typical meta-models, is difficult. The combination meta-model can be used to solve this problem, but the possible number of parameters increases. This causes a cost problem when using FE simulation. In this study, the accuracy of the nonlinear properties of materials and the number of iterations were compared for three typical meta-models and the proposed advanced meta-models considering stress–strain properties. A material property test was conducted using ASTM E8/E8M, and the meta-model was initialized using ASTM E646 and MATLAB Curve Fitting Toolbox. A finite element (FE) simulation was conducted for the meta-models, and the test and simulation results were compared in terms of the engineering stress–strain curve and the root-mean-square error (RMSE). In addition, an inverse method was applied for the FE simulation to estimate the true stress–strain properties, and the results were analyzed in terms of the RMSE and the number of iterations and simulations. Finally, the need for an advanced meta-model that exhibits strong nonlinearity was suggested.

Insight into the Influence of Punch Velocity and Thickness on Forming Limit Diagrams of AA 6061 Sheets—Numerical and Experimental Analyses

In this article, the forming limit diagram (FLD) for aluminum 6061 sheets of thicknesses of 1 mm and 3 mm was determined numerically and experimentally, considering different punch velocities. The punch velocity was adjusted in the range of 20 mm/min to 200 mm/min during the Nakazima test. A finite element (FE) simulation was carried out by applying the Johnson–Cook material model into the ABAQUSTM FE software. In addition, a comparison between the simulation and the experimental results was made. It was observed that by increasing the punch velocity, the FLD also increased for both thicknesses, but the degree of the improvement was different. Based on these results, we found a good agreement between numerical and experimental analyses (about 10% error). Moreover, by increasing the punch velocity from 20 mm/min to 100 mm/min in 1 mm-thick specimens, the corresponding FLD increased by 3.8%, while for 3 mm-thick specimens, this increase was 5.2%; by increasing the punch velocity from 20 mm/min to 200 mm/min in the 3 mm-thick sheets, the corresponding FLD increased by 9.3%.

FE-Simulation Based Design of Wear-Optimized Cutting Edge Roundings

The performance of cutting tools can be significantly enhanced by matching the cutting edge rounding to the process and material properties. However, the conventional cutting edge rounding design is characterized by a significant number of experimental machining studies, which involve considerable cost, time, and resources. In this study, a novel approach to cutting edge rounding design using FEM-based chip formation simulations is presented. Based on a parameterized simulation model, tool temperatures, stresses and relative velocities can be calculated as a function of tool microgeometry. It can be shown that the external tool loads can be simulated with high agreement. With the help of these loads and the use of wear models, the resulting tool wear and the optimum cutting edge rounding can be determined. The final experimental investigations show a qualitatively high agreement to the simulation, which will enable a reduced effort design of the cutting edge in the future.

Prediction of load requirement and instabilities during end forming of friction stir processed AA 6063-T6 thin-walled tubes

PurposeThe current work aims to propose a finite element (FE) simulation methodology to predict the formability of friction stir processed (FSPed) tubes by end forming. Moreover, a strain mapping method is also presented to predict the end forming instabilities.Design/methodology/approachIn this work, FE simulation of end forming of raw tubes and FSPed AA6063-T6 tubes are done using Abaqus (explicit) incorporating anisotropic properties of the raw tube and FSPed zone. Actual thickness of the FSPed zone is also implemented. Expansion, reduction and beading are the end forming operations considered. Load requirement and instabilities are predicted. A new method “strain mapping method” is followed to predict the failure instabilities in expansion and beading, while during reduction, wrinkling is predicted by FE simulations. Lab scale experiments on FSP and end forming are done for validation at various rotational speeds.FindingsResults reveal that in the case of expansion and reduction of FSPed tubes, forming load predictions are accurate, while in beading, after initiation of bead, predictions are not accurate. Experimental observation on the type of instability is consistently predicted during numerical simulations. Prediction of displacement at failure by strain mapping method is encouraging in most of the cases including those that are FSPed. Hence, it is suggested that the method can be utilized to evaluate the onset of failure during tube expansion and beading.Originality/valueFE simulation methodology including anisotropic properties of raw tube and FSPed tubes is proposed, which is not attempted until now even for normal tubes. Strain mapping method is easy to implement for instability predictions, which is done usually by failure theories and forming limit diagram.

Technology Innovation for the Manual Laser Cladding of High-Alloy Tool Steels

This paper presents the development and successful application of an inductive preheating system running simultaneously with the manual laser cladding process in order to enable the repair of high-alloy tool steels having a highly limited weldability. In this study, the design and optimization of a suitable inductor as well as the analysis of the welding process were carried out by means of FE-simulation in order to generate material deposition without imperfections. Parameter variation studies were conducted while parallel modifying the generator power resulting in different preheating temperatures. These examinations showed that by using appropriate process parameters and an inductive preheating temperature of 200 ∘C, crack- and pore-free deposition layers could be produced on the commercial high-alloyed PM steel Elmax. This result can be explained by FE-simulation demonstrating that the cooling rate was halved in the weld and in the heat-affected zone. In conclusion, this study shows the high potential of the developed technical innovation for the manual laser cladding of high-performance tools.

Análisis térmico de los elementos de sujeción del núcleo de un reactor trifásico

In this thesis work the temperature distribution in the frame bolts of a 5 MVA, 115 kV, 60 Hz, three-phase five-limbs shunt reactor is obtained utilizing the finite element method (FEM) and the commercial ANSYS Maxwell software. This because the reactor actually failed while it was running, the failure occurred progressively as the screw insulation was damaged and caused an unwanted temperature rise. A time-harmonic analysis is performed to compute the magnetic field distribution in the reactor and the power losses in the frame bolts. A three-dimensional (3-D) shunt reactor model is utilized, and Maxwell’s equations are solved utilizing scalar and vectorial magnetic potentials. The 3-D electromagnetic shunt reactor model is validated by comparing the value of inductance measured in the laboratory with the value of inductance computed in the 3-D FE simulation. In addition, the core losses computed in the FE simulation are compared with the core losses measured in the laboratory. This thesis work is important for transformer manufacturers which requires an adequate shunt reactor model to analyze it under different operation conditions and to optimize the actual design.