A Methodological Approach for Supporting the Thermal Design of Li-Ion Battery for Customized Electric Vehicles

An important issue in the mechanical industry is the reduction of the time to market, in order to meet quickly the customer needs. This goal is very important for SMEs that produce small lots of customized products. In the context of greenhouse gas emissions reduction, vehicles powered by electric motors seem to be the most suitable alternative to the traditional internal combustion engine vehicles. The market of customized electric vehicles is a niche market suitable for SMEs. Nowadays, the energy storage system of an electric vehicle powertrain consists of several Li-ion cells arranged in a container called battery pack. Particularly, the battery unit is considered as the most critical component in electric vehicle, because it impacts on performance and life cycle cost. Currently, the design of a battery pack mostly depends on the related market size. A longer design time is expected in the case of a large scale production. While a small customized production requires more agility and velocity in the design process. The proposed research focuses on a design methodology to support the designer in the evaluation of the battery thermal behavior. This work has been applied in the context of a customized small production. As test case, an urban electric light commercial vehicle has been analyzed. The designed battery layout has been evaluated and simulated using virtual prototyping tools. A cooling configuration has been analyzed and then prototyped in a physical vehicle. The virtual thermal behavior of a Li-ion battery has been validated at the test bench. The real operational conditions have been analyzed reproducing several ECE-15 driving cycles and many acceleration runs at different load values. Thermocouples have measured the temperature values during the physical experiments, in order to validate the analytical thermal profile evaluated with the proposed design approach.

Positional Accuracy Analysis in Serial Chain and Four-Bar Closed Chain Manipulator

Serial chain robots are integral part of industrial automation. Better reach within workspace, higher Degree of Freedom (DoF), flexibility and positional accuracy are credit performance features behind its wide acceptance. The flexibility and higher DoF of this configuration is underutilized, when it is used for a repetitive task in hard automation. The present paper considers application of closed chain four-bar mechanism as substitute of a serial chain robot for repetitive task involving single trajectory generation. The manipulators are modelled for positional accuracy under the influence of joint clearances and drive backlash. The positional error in both manipulators for a coupler point on sample path is estimated. The manipulators are considered to operate with identical input constraints. The error is expressed in terms of dimensionless number-as Error Index to estimate the comparative behaviour of the manipulators. The paper presents method of analysing the performance of a closed chain manipulator over serial robot.

Visual Product Evaluation: Using the Semantic Differential to Investigate the Influence of Basic Geometry on User Perception

Products evoke emotions in people. Emotions can influence purchase decisions and product evaluations. It is widely acknowledged that better product performance and higher user satisfaction can be reached through aesthetic design. However, when designing a new product, most of the attention is generally paid to enhance its functionality and usability and much less consideration is given to the emotional needs of users. This paper investigates the connection between emotions and product features. Various forms of vases are used as a product case. Additionally, a compact list of product-specific semantic descriptors is first developed using a classification based on Jordan’s four pleasures model. Paper-based surveys, face-to-face interviews, and statistical methods were performed in this paper, where significant correlations between semantic descriptors and product geometry were found. Prototypes of two vases were developed based on elicited emotions and a short validation on aesthetic value was performed. Our results show core set of geometric features of a vase have the strongest impact on emotional responses from users: the opening of the neck, the height of the neck, the base of the neck (width), and the base (width).

Framing Engineering Problems: Basic Concept

There are two kinds of knowledge in engineering. One is rational knowledge. We understand the phenomena and we can apply rational approaches. The other is knowledge about phenomena which we do not understand well, but which we can control and utilize for engineering. For example, we do not understand arc phenomena well, although there are tremendous amount of work about arc. If we do, we could prevent thunder and lightning. However, we utilize arc for welding. Without arc, most of our bridges, buildings, etc would not have been built. As Engineering is a DO activity and we do not have to UNDERSTAND the phenomena as scientists do. What is very important in engineering is how we can utilize such knowledge about these phenomena, which we do not understand well, but which we can control. And to develop a safe and secure system, we have to let them work in good harmony. This is the problem of frames as AI researchers call it. Although this is still an open question in AI, engineers have to go beyond the bounded rationality. This paper describes the basic concept of how we engineers could possibly tackle this problem.

Methodology for a Partly Automated Parameter Identification for the Validation of Multi-Domain Models

The paper presents a methodology for a partly automated parameter identification that is to validate multi-domain models. To this end an identification tool under MATLAB has been developed. It enables a partly automated procedure that uses established methods to identify parameters from complex, nonlinear multi-domain models. In order to integrate such multi-domain models into the tool, an interface based on the Functional Mock-up Interface (FMI) standard can be used. The interface makes the required identification parameters from the multi-domain model automatically available to the identification tool. Additionally a guideline is developed which describes the way in which the respective domain expert has to mark the required identification parameters during modeling. The needs for this methodology as well as its application are shown by a practical example from the industry, using Dymola, the FMI-standard, and MATLAB. The practical example deals with the model-based development of a new washing procedure. The paper presents a partly automated parameter identification for the validation of the absorption part of the multi-domain model. Besides, new approaches to the modelling of this kind of absorption effects will be detailed.

Conceptual Design Optimization With Economic Uncertainty: An Application to Interactions Between Designers and Airlines

Many engineering problems involve interactions between multiple decisions makers, or stakeholders, each with their own objectives and uncertainties. Considering these interactions during design optimization allows us to account for new sources of uncertainty, which we refer to as economic uncertainty. In this paper, we consider an application of optimization considering interactions between aircraft designers and airlines based on the design of a commercial transport aircraft wing. We consider that the aircraft designer makes their design decisions first, and therefore must predict the reaction of the airline. We focus on the effect of two economic uncertainties: uncertainty that would normally only affect the airline and uncertainty due to asymmetric information, or errors in the designers’ understanding of the airlines’ preferences. We find that these uncertainties play a significant role in the optimal decisions by both airlines and designers. We also show that asymmetric information may actually be beneficial for both stakeholders in certain cases, where both players benefit from the aircraft designer underestimating the operating costs of the airline.

Quantification of Uncertainty in Sketches

Design Notebooks (DNBs) can be used to assess the information gathering activities, creativity and individual participation within design groups. Moreover DNBs are the communication tools in the overall design process. For communication purposes, DNBs contain information representations (IRs) such as sketches, symbols, text and equations that usually are imprecisely defined. Imprecise or vague IRs may lead to uncertainty in design communication. This work considered the uncertainty in sketches, one of the most widely used IRs in DNBs. The research question of this study is: Can the uncertainty in sketches be quantified? To answer the research question the following specific aims are formulated: identify the type of uncertainty, assess appropriate uncertainty quantification methods and establish a framework to quantify the uncertainty in sketches. The uncertainty in sketches is found to be mainly an epistemic uncertainty and a modified numerical approach was implemented to quantify it. Using the established framework, the uncertainty in sketches has been quantified and further study is recommended to assess its effect on design communication.

Structural Integrity and Mechanical Design of a Probe of High Pressure and High Temperature for Oil Wells Applying Finite Elements Tools

Measurement of high pressure and high temperature (HPHT) tools is regularly carried out in the hydrocarbons sector to determine not only the characteristics and performance of fluids inside the well, but also to evaluate the mechanical condition of the pipes and the automation of production. The mechanical features of these tools are significantly influenced by the mechanical design of the structure, which eventually affects their performance and integrity. This paper describes the design process and the analysis of the structural integrity of a HPHT measuring tool for oil wells in its sensors section. The classical theories of mechanical design and specifications of the ASME boilers and pressure vessels code were used. The study is performed for several operation variables in a numerical model using a commercial code of finite element method to determinate the maximum principal stresses, total displacements and safety factor in the mechanical elements that form the device. The numerical results were compared with the experimental data source from the laboratory tests.

Optimum 3D Rapping of CAD Models Using Single NURBS

Non-Uniform Rational B-Splines (NURBS) can represent curves and surfaces of any degree. Usually in the same curve, however, the degree is unique. The goal of this work is to identify single and exact corner point of lines represented by cubic or other NURBS. The combination of arcs and lines can then be represented by one NURBS with error not to exceed (10−12). The developed procedure can represent any NURBS curve and surface of any degree with full control on all parameters, control points, weights, knot vectors, and number of segments representing the curve or surface, in addition to, the basis functions examination. The optimization identifies the parameters and geometry to insure any required level of accuracy to represent singular corner solid models to allow a single cubic or other NURBS representing the whole solid. It is concluded that the singular corner point can be identified with cubic NURBS. Applications to several 3D solid CAD models are used to verify such a technique.

Effect of Rim Thickness on Tooth Root Stress and Mesh Stiffness of Internal Gears

In recent years, internal gears are used commonly in a number of automotive and aerospace applications especially in planetary gear drives. Planetary gears have many advantages such as compactness, large torque-to-weight ratio, large transmission ratios, reduced noise and vibrations. Although internal gears have many advantages, there are not enough studies on it. Designing an internal gear mechanism includes two important parameters. The gear mesh stiffness which is the main excitation source of the system. In this paper, 2D gear models are developed in order to compute gear mesh stiffness for various rim thicknesses and different rim shapes of the internal gear design. Effects of root stress with varying rim thickness and some tooth parameters are investigated by using 2D gear models. The stress calculated according to ISO 6336 and the stresses calculated against FEM are compared. These results are well-matched. It is observed that when the rim thicknesses are increased, both the maximum bending stresses and gear mesh stiffness are decreased considerably.