Papers by Keyword: CAE

Abstract: In this article the issues related to Computional Fluid Dynamics of the occurrence of innovative aerodynamic effect were presented. Analysis were performed to determine the occurrence of Kammback aerodynamic effect and its application in a shape of a body of the real racing car in order to minimize drag forces of the vehicle. For the analysis, ideal aerodynamic shapes were modeled, subsequently they were subjected to modifications which were used to determine the occurrence of effect. The basic modeled shape was the raindrop shape solid, which is generally regarded as the ideal shape in terms of aerodynamics. The result of analysis was compared with the drag values known from the literature. Afterwards changes in the shape of the base solid were made to verify and determine the optimum Kammback shape, selected from a set of possible solutions, in which the geometrical changes has the lowest difference of values of drag force and drag coefficient Cx(Cd) in comparison to the basic raindrop shape. Results of the study were subjected to graphic analysis, especially the distribution of air pressure on the surface of a solid and in a virtual wind tunnel, distribution of the air velocity and the course of air streams around the shape. The results were used to design the body of electric race car. The main objective was to minimize the aerodynamic drag of the vehicle.

Abstract: In this paper issues of stress analysis of composite materials are presented. The components of composite materials and principles of composition has been discussed. Particular attention was paid to the epoxy resins and the fabrics made from carbon fibers. The article also includes basic information about strain measurements performed on with a resistance strain gauge method. For the purpose of the laboratory tests a series of carbon - epoxy composite samples were made. The main aim of the studies was to compare the results of two different research methods – laboratory and simulation method. During laboratory strain tests described in the paper, a composite samples were loaded with a specified load. Tenmex's delta type strain gauge rosettes were used to measure strain. They were arranged in specific locations on the surface of the samples. Data acquisition procedure were carried out using HBM measurement station. Numerical studies were carried out in a computing environment, Siemens NX 9.0. The results of simulation and laboratory tests were compared and presented in the form of graphs. They allow you to validate the method of laboratory measurements. The results of both research types have shown the percentage difference between them for individual loads applied to each composite.

Abstract: In this paper an analysis of the stress state of the hull of the ship Kormoran II loaded by non-contact mine explosion were performed. An empirical description of the pressure wave from the non-contact TNT explosion loads reported by authors such as RH Cole T. L. Geers and K.S. Hunter was used. The way of modeling the pressure wave using the acoustic medium implemented CAE programs was shown. The paper presents the results of pressure distribution on the hull of the ship Kormoran II at selected time points from TNT explosion under the keel of the ship. The paper presents detailed results of the stress state in the selected nodes, for example on the frame of main motor construction.

Abstract: Sheet hydroforming has gained increasing interest in the automotive and aerospace industries because of its many advantages such as higher forming potentiality, good quality of the formed parts which may have complex geometry. The main advantage is that the uniform pressure can be transferred to any part of the formed blank at the same time. This paper reports numerical and experimental correlation for symmetrical hydroformed component. Experimental tests have been carried out through the hydroforming cell tooling, designed by the authors thanks to a research project, characterized by a variable upper blankholder load of eight different hydraulic actuators. The experimental tests have been carried out following a factorial plane of two factors, with two different levels for each factor and three replicates for each test with a total of 12 tests. In particular two process parameters have been considered: blank holder force, die fluid pressure. Each factor has been varied between an High (H) and Low level (L). The order in which have been conducted the tests has been established through the use of the Minitab software, in order to ensure the data normality and the absence of auto-correlation between the tests. An ANOVA analysis has been performed, in addition, with the aim of evaluating the influence of process parameters on the thickness distribution of the component, its formability and feasibility. Finally, finite element analysis (FEA) was used to understand the formability of a material during the hydroforming process. In this paper, the commercial finite element code LS-Dyna was used to run the simulations. A good numerical – experimental correlation has been obtained.

Abstract: The authors have investigated, in other paper, the problem related to the definition of a “set of shape factors” in order to declare the feasibility of a product through sheet hydroforming. In particular the defined shape factors are three different a-dimensional coefficients by which it is possible to declare the feasibility of a product through the calculation, in different sections, of the three previous shape factors. The robustness of this methodology is related to the correct calculation of the “limit value” of each shape factor. In fact the feasibility is reached if, in any section, the calculated shape factors are higher than their respective limit values. In this paper the authors have performed an extensive numerical and experimental campaign, taking into account a different geometry respect to that of the first paper, in order to: re-calculate the limit value for each shape factor and, then, verify the correctness of the limit values exposed in the previous first paper. The numerical campaign has been used, after the evaluation of the accuracy of the numerical model, in order to study the feasibility of the product without engaging the hydroforming machine. Finite Element Analysis (FEA) has been extensively used in order to investigate and define each shape factor with a proper comparison to the macro feasibility of the chosen component geometry. The limit values that have been calculated by the authors in this paper are slightly different from those calculated in the first paper. From this point of view it is possible that, although the shape factors are a-dimensional coefficients, they are affected by different choices of the users as, for example, the dimensions of the initial blank. Anyway, the small differences in the shape factors limit values do not adversely affect the use of the shape factors in order to predict the feasibility of the product.

Abstract: The automotive development process is advancing through the utilization of CAD/CAM/CAE. This advancement is being enhanced by proper utilization of CAD/CAM integration, Digital prototyping and Digital mock-up. Until recently, CAD has played the leading role for the digitalization of automotive development. However, recent trend shows that, the leading role is shifted from CAD to analysis simulation. Three-dimensional design, which utilizes digital mock-up, is becoming the main tool for product design. Here, the functional capability and predictive assessment by CAE is the core technology. In addition, this supporting role is helping to realize the concurrent engineering in production engineering field.

Abstract: Cement-Emulsifying Asphalt and waterborne Epoxy (CAE) cementing materials meet requirement for paving in steel bridge deck pavement materials, which possessing good flexibility, high temperature stability and cohesiveness to steel plate, and the microstructure model and structure formation mechanism of CAE mortar was researching in this paper. The results of the study show that, CAE mortar forms the asphalt and epoxy interpenetrating network structure which connect with cement, and the forming process contains four stage, which is dispersedness, interaction, structure formation and strength development. This structure makes CAE concrete give full play to such characteristic, which is good adhesion of cement with asphalt and epoxy resin, good temperature stability and high bonding strength of epoxy resin, good toughness of asphalt.

Abstract: In a certain vehicle of Dongfeng Passenger Vehicle Company (DFPV), a new design of integrated hot stamping B-pillar reinforcement panel is introduced to replace the original design of two cold stamping parts connecting by spot-weld. A further light-weight design by thickness thinning is also attempted. All the schemes are validated by hot stamping process simulation and vehicle side impact simulation. The results show that by using hot-stamping steel of the same thickness as the original design, the performance of anti-vehicle side impact is improved; and an equivalent anti-side impact performance can be achieved by appropriate thickness reduction, while the weight of the part is lightened.

Abstract: In this paper thermal simulation of a satellite borne electric box is introduced. Structure was simplified and a finite element model was built. The analysis results showed that the temperature scopes of the box and the component cases are from 45°C to 67.3°C and all of junction temperatures of the components are lower than the derated maximum junction temperatures themselves and leave enough design margins, which match the requirements of thermal analysis.

Abstract: Cold forging die design and process simulation were studied in this paper for a disk with center boss and outer ring gear. The complexity of part geometry results in defects of under-filling and folding. The material flow interference in the radial and the axial directions at the corner areas is the main reason of the occurrence of defects. A multi-stage cold forging process was proposed to control the material flow and volume distribution simultaneously. FEM simulations were carried out to evaluate the designs of process and die. The proposed preform and web geometry designs were able to decrease the forging load and control the material flow. The simulation results showed the proposed methods were able to make this forged part without defects.