Simulation akustischer Produkteigenschaften unter Nutzung der Virtual Reality während der Produktentwicklung

In der Dissertation werden Grundlagen zur Nutzung der audio-visuellen VR in der Produktentwicklung erarbeitet. Damit die akustischen Produkteigenschaften technischer Systeme in der VR hörbar gemacht werden können, wird eine Repräsentation für diese Eigenschaften, verbunden mit der Gestaltbeschreibung, geschaffen. Ein Schwerpunkt der Untersuchungen ist die Repräsentation der richtungsabhängigen Schallabstrahlung technischer Systeme im VR-Modell. Weiterhin werden Modelle entwickelt, die eine echtzeitfähige Simulation akustischer Produkteigenschaften auf der Körperschallebene ermöglichen. Hierfür wird eine komponentenweise Modellierung eingeführt. Durch eine generische Modellierung mit getrennter Datenhaltung und bereitstellung lassen sich die Parameter den Modellen effizient zuweisen. Für den Datenaustausch zwischen Simulations- und VR-Modell wird ein Kommunikationsserver entwickelt. Anhand eines Anwendungsbeispiels werden die Vorteile der parametrischen Modellbeschreibung erörtert.This thesis is about the use of audio-visual Virtual Reality (VR) during the product development process. In order to represent acoustical information in the virtual product model the VR scene graph is enhanced by special sound-nodes which are linked to the struct ure and geometry information. Thus, a first evaluation of the acoustical product behaviour is possible by using empiric acoustic data, a component-wise representation in the scene graph, and interactive manipulation methods which allow for real-time adaptation of the sound field. Real components are characterised by a direction-dependent sound radiation. Therefore, two concepts for the representation of the directional characteristic of technical systems are developed using monopole-sources. The monopole-sources can be integrated directly into the scene graph. The concepts are evaluated by using examples. The main part of the thesis explains the real-time simulation of structure borne sound stimulation and transmission. A component-wise representation approach is introduced for efficient modelling. The component models can be connected to more complex technical systems via interfaces, implying effort and flow variables. Parametric, simplified models are developed for some stimulation mechanisms, which calculate the stimulation spectrum according to the design parameters of the product and its current state in real-time. In addition, measured sound spectra are used. The simulation of structure borne sound transmission is based on a four-pole approach. Different parameter identification methods for these four-poles are discussed. In order to simulate the acoustical product properties the current kinetic state of the technical system has to be known. For this purpose, state models are developed, which can be coupled with the acoustic models. For the real-time information exchange between simulation model and VR-model a communication server is developed. The simulation models and methods are evaluated via an application example. The example is also used to demonstrate the advantages of parametric modelling.In der vorliegenden Arbeit werden Grundlagen zur Nutzung der audio-visuellen Virtual Reality (VR) in der Produktentwicklung erarbeitet. Damit die akustischen Produkteigenschaften technischer Systeme in der VR hörbar gemacht werden können, wird eine Repräsentation für diese Eigenschaften, verbunden mit der Gestaltbeschreibung, geschaffen. Unter Nutzung empirischer Daten, einer komponentenweisen Repräsentation im Szenengraph und einfacher Manipulationsmöglichkeiten zur Anpassung des Schallfeldes in Echtzeit können erste Bewertungen des akustischen Produktverhaltens durchgeführt werden. Ein Schwerpunkt der Untersuchungen ist die Repräsentation der richtungsabhängigen Schallabstrahlung technischer Systeme im VR-Modell. Im Rahmen der Arbeit werden zwei indirekte Methoden zur Repräsentation der Richtcharakteristik durch räumlich verteilte Monopole erarbeitet, so dass sich die Repräsentation direkt in den VR-Szenengraph einbinden lässt. Die Methoden werden anhand konkreter Beispiele verifiziert. Im Hauptteil der Arbeit werden Modelle entwickelt, die eine echtzeitfähige Simulation akustischer Produkteigenschaften auf der Körperschallebene ermöglichen. Hierfür wird eine komponentenweise Modellierung eingeführt. Über Schnittstellen mit Potential- und Flussgrößen können die Komponentenmodelle zu komplexeren technischen Systemen zusammengesetzt werden. Für die Anregungssimulation werden für einzelne Anregungsmechanismen vereinfachte Modelle entwickelt, welche über Produktmerkmale parametrisiert werden und in Abhängigkeit von Zustandsparametern die Berechnung der Anregungsspektren in Echtzeit ermöglichen. Außerdem werden empirisch erfasste Körperschallspektren verwendet, welche über Kennfelder abgebildet werden. Zur Simulation der Körperschallübertragung werden Modelle entwickelt, welche auf dem Konzept der Vierpole beruhen. In der Arbeit werden unterschiedliche Methoden der Parameterbestimmung für die Vierpole erörtert. Die entwickelten Modelle werden als Signalflussmodelle implementiert. Durch die generische Modellierung der Vierpole mit getrennter Datenhaltung und -bereitstellung lassen sich die Vierpolparameter den Körperschallmodellen effizient zuweisen. Für die Durchführung einer Akustiksimulation muss eine Simulation des aktuellen Betriebszustandes eines technischen Systems vorgeschaltet werden, damit die veränderlichen Potential- und Flussgrößen als Eingangsgrößen für die Akustiksimulation in jedem Simulationsschritt vorhanden sind. Für den Datenaustausch zwischen Simulations- und VR-Modell wird ein Kommunikationsserver entwickelt. Anhand eines Anwendungsbeispiels werden die entwickelten Modelle validiert und die Vorteile der parametrischen Modellbeschreibung erörtert

Methodical procedure for a surrogate model based fatigue calculation to support the design process of eBike drive units

In this paper, a method is developed to consider multiaxial load spectra and their variation in a computationally efficient local fatigue calculation procedure. This method is based on an FE data-based surrogate model and is intended to support the simulation-based product design process. To demonstrate their application and necessity, a case study on the design of eBike drive units is presented. For this purpose, the general requirements for the design of eBike drive units as well as the fundamentals of multiaxial fatigue analysis and surrogate modeling are outlined. In addition, a validation process of the surrogate model and its use for fatigue calculation is presented and discussed

Analysis of potential errors in technical products by combining knowledge graphs with MBSE approach

Technical products are developed to meet the demands of stakeholders. Therefore, the product's functions and associated properties are important. Various influencing factors e.g., external disturbances can have an impact on the input flows of the products or its characteristics and thus on the functions. If this leads to deviations between the required and as-is functions, these deviations are called errors. It is therefore important to analyze errors in product development and implement measures to increase the robustness of the product. Model-Based Systems Engineering (MBSE) supports the development of complex systems. However, MBSE alone has limited ability to identify in-depth errors. This requires knowledge of possible errors from previous products in specific contexts. For this purpose, the method proposed in this paper facilitates identifying errors in the concept phase by combining MBSE approaches with reusable knowledge (i.e., knowledge graph). The approach is presented using an application example for a mobile robot

Sustainability strategies and their influence on the product development of machine tools and special machines

In the context of product development, the goal of developers is to design products based on a variety of stakeholder needs so that they sufficiently satisfy a wide range of required characteristics. The required properties relate to function, safety, manufacturability, cost, usability, etc. In recent years, sustainability has gained importance as an additional and now indispensable guiding principle in product development due to the rapidly growing global environmental, social and economic challenges. The focus of this paper is on sustainability, which takes into account resource consumption, environmental protection and ecology. The same applies to the circular economy as an essential component of sustainability strategies when it comes to product or material cycles, as well as the targeted repair, reuse, modification, waste prevention and upgrading of products, etc. A product category that is rarely in the public eye is machine tools and special machines. In order to consistently consider sustainability and the associated circular economy in the development of these machines, product developers need practice-oriented and methodically validated decision-making means. The paper discusses and systematizes possible sustainability strategies and their implications from different perspectives, such as business models or applicability

Systematic use of model-based solution patterns using the example of a load cell

Complex mechatronic products are usually decomposed into several sub-systems for their development. These sub-systems are developed in parallel or even independently based on their specifications and use cases. The application of model-based solution patterns is an effective way to comprehensively and efficiently describe the available knowledge about the sub-systems. This contribution proposes an approach to support the selection and application of model-based solution patterns. The approach, based on a metamodel for solution patterns using SysML, describes the process for selecting solution patterns and aligning requirements and constraints with the as-is properties of the sub-systems. Additionally, the approach supports the design of solution patterns taking into account special knowledge from the development of the sub-systems as well as the usage of the solution patterns in different systems and contexts. As an example, an application scenario of a specific load cell within a measurement system is explained

Error classification as a basis for automating the conformity of production process in the automotive industry

In the automotive industry, the complexity of ensuring production conformity has increased significantly. Reasons for this are a growing number of vehicle variants in combination with increasing regulatory requirements in import markets. Violations of the "Conformity of Production" (CoP) can result in drastic penalties. This is contrasted by a partially random and manual inspection process that is currently not sufficiently automated and digitalized. According to the BMW Group CoP expert workshop there is not enough error analysis and classification in the current situation to comprehensively perform automated inspections. To gain more insight into this manual inspection process, a comprehensive error analysis and classification must first take place to derive measures. Based on the requirements for the CoP process and the findings from the state of the art, the objective of this contribution is to analyze the status quo regarding error frequencies and to derive possible measures from the findings

An AI-driven design method as basis for teaming

The product development process could benefit from a synergistic human-machine teaming, potentially shortening product development cycles and improving product performance and sustainability. However, there is a lack of available methods to achieve this goal. A technical product has to satisfy numerous requirements. Due to the variety and complexity of these requirements, the design process is challenging for human engineers. While engineers are supported by various tools (e.g. FEM) for analyzing product properties, tools for computer-aided synthesis of product properties considering the corresponding requirements are still only available in exceptional cases. However, such synthesis capabilities are necessary to qualify a computer-aided tool for productive teaming with engineers. Special methods based on artificial intelligence show a high potential for general computer-aided synthesis methods. This contribution presents an innovative approach in this direction based on topology optimization techniques

Modeling of corner-filleted flexure hinges under various loads

Compliant mechanisms are widely applied in precision engineering, measurement technology and microtechnology, due to their potential for the reduction of mass and assembly effort through the integration of functions into fewer parts and an increasing motion repeatability through less backlash and wear, if designed appropriately. However, a challenge during the design process is the handling of the multitude of geometric parameters and the complex relations between loads, deformations and strains. Furthermore, some tasks such as the dimensioning by means of optimization or the modeling for a controller design require a high number of analysis calculations. From this arises the need for sufficient computational analysis models with low calculation time. Existing studies of analysis models are mostly based on selected load cases, which may limits their general validity. The scope of this article is the comparison of models for the analysis of corner-filleted flexure hinges under various loads, to determine their advantages, disadvantages and application fields. The underlying methods of the study can further be used to evaluate future models based on a broad selection of possible load cases

Systematization of existing uncertainties in the context of product development in the automotive supply industry

Along the development process of technical products, challenges arise repeatedly, which result from uncertainties, i.e., conscious, or unconscious gaps in knowledge or definitions. The causes often lie in the fact that empirical values represent the basis for many decisions, from the specification of tasks to the required organizational and control structures to the models and calculation tools used. Based on this knowledge, it is essential to continuously identify, evaluate and, if necessary, reduce the degree of uncertainty during the development of innovative products. This is intended to avoid potentially negative influences on the strategic goals of the magic triangle of project management (costs, time, and quality). This is exactly where the investigations started, using the example of an automotive supplier company. Completed projects are the starting point. A first focus is on the analysis of the effects of unclearly defined requirements and ambiguities in verification, validation, and end customer use. A second focus is the systematization, classification up to the provision of project-specific tools, which should facilitate the reduction of uncertainties already in early project phases

The Translation between Functional Requirements and Design Parameters for Robust Design

AbstractThe specification of and justification for design parameter (DP) tolerances are primarily based on the acceptable variation of the functions’ performance and the functions’ sensitivity to the design parameters. However, why certain tolerances are needed is often not transparent, especially in complex products with multi-disciplinary development teams. In those cases, tolerance synthesis and analysis get complicated which introduces ambiguities and difficulties for system-integrators and lead engineers for the objective decision making in terms of trade-offs but also in terms of an efficient computer aided functional tolerancing. Non-optimal tolerances yield potentials for cost improvements in manufacturing and more consistency of the functional performance of the product. In this contribution a framework is proposed to overcome the observed problems and increase the clarity, transparency and traceability of tolerances by analyzing the translation between the DPs and their influence on the final function