Poetsch C.,Virtual Vehicle Research and Test Center |
Ofner H.,AVL List GmbH |
Schutting E.,University of Graz
SAE Technical Papers | Year: 2011
The paper describes a universally structured simulation platform which is used for the analysis and prediction of combustion in compression ignition (CI) engines. The models are on a zero-dimensional crank angle resolved basis as commonly used for engine cycle simulations. This platform represents a kind of thermodynamic framework which can be linked to single and multi zone combustion models. It is mainly used as work environment for the development and testing of new models which thereafter are implemented to other codes. One recent development task focused on a multi zone combustion model which corresponds to the approach of Hiroyasu. This model was taken from literature, extended with additional features described in this paper, and implemented into the thermodynamic simulation platform. Within this environment the models were systematically assessed by analysis and identification of the mechanisms which predominantly control the combustion process and the formation of NO and Soot. Due to the flexibility of the simulation platform the multi zone model could be directly compared with a conventional 2-zone model. For the assessment a systematic procedure was developed which clearly depicts the advantages of the multi zone approach. The assessment also resulted in identified model parameters. In applying them to measurements of three different engines, the quality of the models (multi-zone vs. 2-zone) is demonstrated and discussed. Copyright © 2011 SAE International.
Brandl M.,Austriamicrosystems AG |
Gall H.,Austriamicrosystems AG |
Wenger M.,Fraunhofer Institute for Integrated Systems and Device Technology |
Lorentz V.,Fraunhofer Institute for Integrated Systems and Device Technology |
And 10 more authors.
Proceedings -Design, Automation and Test in Europe, DATE | Year: 2012
The battery is a fundamental component of electric vehicles, which represent a step forward towards sustainable mobility. Lithium chemistry is now acknowledged as the technology of choice for energy storage in electric vehicles. However, several research points are still open. They include the best choice of the cell materials and the development of electronic circuits and algorithms for a more effective battery utilization. This paper initially reviews the most interesting modeling approaches for predicting the battery performance and discusses the demanding requirements and standards that apply to ICs and systems for battery management. Then, a general and flexible architecture for battery management implementation and the main techniques for state-of-charge estimation and charge balancing are reported. Finally, we describe the design and implementation of an innovative BMS, which incorporates an almost fully-integrated active charge equalizer. © 2012 EDAA.
Nubaumer C.,Virtual Vehicle Research and Test Center |
Schmidt L.,DCC Doppelmayr Cable Car GmbH and Co KG |
Dietmaier P.,University of Graz
Vehicle System Dynamics | Year: 2012
The objective of this study is to develop a three-dimensional multibody system (MBS) for the dynamic simulation of rope-propelled automated people movers (RAPM). These public transport systems include guided vehicles which operate in a fully automated mode on a separate guideway. In design stage of an RAPM the optimisation of ride comfort and durability is aspired. Therefore, an elastic rope model has been implemented in a state-of-the-art MBS software. The coupling of the rope model with standard MBS elements allows for the integrated simulation of these transport systems which will enhance the prediction quality of the overall system dynamics. © 2012 Copyright Taylor and Francis Group, LLC.
Kitting D.,Virtual Vehicle Research and Test Center |
Ofenheimer A.,Virtual Vehicle Research and Test Center |
Pauli H.,Voestalpine AG |
Till E.T.,Voestalpine AG
AIP Conference Proceedings | Year: 2011
Deformation conditions of combined stretching and bending are known to enhance material formability compared to forming conditions without bending (e.g. in-plane stretching). These phenomena can be observed for most conventional steel grades but is even more pronounced for Advanced High Strength Steel (AHSS) sheets. Consequently, there is an urgent need in industry to quantify the phenomena of enhanced material formability due to bending effects. In this work new stretch-bend test setups are presented which can be used in addition to the conventional Angular Stretch Bend Test to systematically investigate the influence of various stretch-bending deformation conditions on the formability of AHSS sheets. © 2011 American Institute of Physics.
Hillebrand J.,Virtual Vehicle Research and Test Center |
Reichenpfader P.,Virtual Vehicle Research and Test Center |
Mandic I.,Magna E Car Systems GmbH and Co. OG |
Siegl H.,Magna E Car Systems GmbH and Co. OG |
Peer C.,Magna E Car Systems GmbH and Co. OG
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011
The development of safety-critical electric/electronic (E/E) automotive systems is performed by an increasing number of software tools. Hence it is very important that software tool malfunctions do not have an impact on the final product. This paper proposes a systematic methodology to establish confidence in the usage of software tools. The approach has been developed on the basis of an industrial development project and is compliant to the framework required by the standard ISO 26262. The methodology is based on a multi-layered analysis that systematically identifies the risk of tool-introduced errors and error detection failures and allows for the derivation of the tool confidence level (TCL). The benefit of this methodology is to identify and reuse already existing verification measures in the development process for establishing confidence in the usage of software tools. Furthermore, the approach allows introducing new verification measures to optimize the overall development process. © 2011 Springer-Verlag.
Schalk-Kitting D.,Virtual Vehicle Research and Test Center |
Weiss W.,Virtual Vehicle Research and Test Center |
Suhr B.,Virtual Vehicle Research and Test Center |
Koplenig M.,Virtual Vehicle Research and Test Center
Key Engineering Materials | Year: 2015
The state of deformation in deep drawing operations is characterized by superimposed stretching and bending (i.e. stretch-bending). Bending effects, especially for Advanced High Strength Steels (AHSS) are known to influence the material formability. Traditional formability measures such as the Forming Limit Curve (FLC) fail to reliably predict stretch-bending formability. Consequently, to ensure an efficient and economical use of AHSS in the industrial application, current research work is focusing on the reliable numerical prediction of stretchbending formability of AHSS sheets. Within this work, a phenomenological concept to predict the forming limit (e.g. the onset of necking) in deep drawing processes taking bending effects into account is presented. The proposed concept is based on curvature-dependent (i.e. regarding the principle curvatures κ1 and κ2 of the stretch-bend (convex) sheet surface) forming limit surfaces representing the probability of failure and is calibrated with experimental results from stretch-bending tests and conventional forming test such as a Nakazima test. The results of the phenomenological forming limit criterion are promising and show a more accurate prediction of the drawing depth at failure than the conventional FLC approach. The method contributes also to a probabilistic view on the forming limit of deep drawing parts. © (2015) Trans Tech Publications, Switzerland.
Rejlek J.,Virtual Vehicle Research and Test Center |
Priebsch H.H.,Virtual Vehicle Research and Test Center
SAE Technical Papers | Year: 2011
Driven by both the ever more restrictive legal regulations on human exposure to noise and the growing customers' expectations regarding the functional performance of a product, the vibro-acoustic behaviour of the product have gained a significant importance over the last decades. At the same time, product development phase and costs have been reduced in order to comply with the nature of competitive market. To cope with those conflicting design targets, the computer aided engineering (CAE) became an essential part of the product design process. A broad class of engineering vibro-acoustic problems involves the mutual coupling interaction between the structure and fluid. In this type of problem, the back-coupling effects are no longer negligible and the problem has to be considered as a fully coupled system. The conventional state-of-the-art techniques adopt the element-based schemes, such as the finite (FEM), boundary (BEM) and infinite element method (I-FEM). The inherent non-symmetric nature of a coupled system, however, compromises the computational efficiency of the uncoupled sparse solvers, mainly due to the high bandwidth of the system matrices. As a result, the practical applicability of these methods is restricted for a limited frequency range. Application of these techniques above the problem-specific frequency limit yields prohibitively large numerical models, which involve a huge amount of computational resources and are thus less efficient. The presented paper discusses the concept and application of the Wave Based Technique (WBT) for the analysis of three-dimensional fully coupled vibro-acoustic problems involving unbounded acoustic domains. In this type of formulation both the structural thin plate bending problem and the unbounded acoustic problem are described by means of a coupled wave based model. The both parts of the coupled problem are solved simultaneously in order to account for the strong coupling interaction. The application of the proposed approach to various validation examples demonstrates its enhanced computational efficiency compared to state-of-the-art techniques. Copyright © 2011 SAE International.
Krammer M.,Virtual Vehicle Research and Test Center |
Martin H.,Virtual Vehicle Research and Test Center |
Karner M.,Virtual Vehicle Research and Test Center |
Watzenig D.,Virtual Vehicle Research and Test Center |
Fuchs A.,Virtual Vehicle Research and Test Center
SAE Technical Papers | Year: 2013
Functional safety of automotive embedded systems is a key issue during the development process. To support the industry, the automotive functional safety standard ISO 26262 has been defined. However, there are several limitations when following the approach directly as defined in the standard. Within this work, we propose an approach for the integration and test of safety-critical systems by using system modeling techniques. The combination of two state-of-the-art modeling languages into a dedicated multi-language development process provides a direct link between all stages of the development process, thus enabling efficient safety verification and validation already during modeling phase. It supports the developer in efficient application of requirements as defined by ISO 26262, hence reducing development time and cost by providing traceable safety argumentation. Based on a hybrid electric power train scenario, we evaluate the benefits of the proposed system modeling approach for early verification and validation of safety-critical embedded systems. Copyright © 2013 SAE International.
Meierhofer A.,Virtual Vehicle Research and Test Center |
Hardwick C.,University of Sheffield |
Lewis R.,University of Sheffield |
Six K.,Virtual Vehicle Research and Test Center |
Dietmaier P.,Graz University of Technology
Wear | Year: 2014
When adding substances to the wheel-rail contact, they mix with wear particles and form a Third Body Layer (3BL). This layer influences the initial gradient of the traction characteristic.During twin-disc tests presented in this paper, a granular layer consisting of iron and iron oxides with a thickness of up to 50 μm was found. In addition, a creepforce model is presented that uses non-linear properties of the 3BL to describe its influence on the traction characteristic. The results of the model were compared to the results of the experiment. A qualitative and quantitative agreement was achieved. This will improve, e.g., the quality of vehicle dynamics simulations, optimizations of control devices for traction and braking, and predictions of wear and damage on wheel and rail. © 2013 Elsevier B.V.
Karas L.,Virtual Vehicle Research and Test Center |
Jalics K.,Virtual Vehicle Research and Test Center |
Priebsch H.-H.,Virtual Vehicle Research and Test Center
Advanced Engineering Materials | Year: 2011
A special approach is required when applying common simulation techniques (e.g. finite elements methods) for vibro-acoustic analysis (natural and force vibrations, mode shapes) to cellular metals. While models using average values for Young's module and for the material density are not sufficiently precise - especially when the material is strongly inhomogeneous, in contrast, simulation using precise microstructure information is not time efficient. Therefore, the main challenge is to map the material microstructure information to the vibro-acoustic simulation model with acceptable efficiency. In this paper, a multiscale technique with representative volume elements is used for this purpose. The results from this approach are validated for a truck oil pan made from closed-cell aluminium foam with strong variations in the microstructure. The investigations show that with more detailed microstructure information the simulation precision can be improved significantly. The simulation results for the natural frequencies show a good agreement (to within 5%) with the values from experiment. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.