Projects at the chair and the research group

Tribological-Mechanical Systems

Service Strength

The determination of the behaviour of tribological-mechanical systems - to improve the understanding of constructional units, for the identification of limits of stress, for optimization or for the creation of tribological simulations - is the goal of this comprehensive area. Against this background, the research group developed an applicable superordinate methodology in particular for sliding bearings and joints running in dry and boundary friction area. The system description includes internal causal directions. Mechanical Behaviour: surface preassure, velocity FE-contact analysis, reduced stiffness matrices out of FE, parametrical models, ... Thermal Behaviour: temperature on sliding surface thermal FE-analysis, identified/reduced multibodymodels, parameter-open models, ... Tribological Behaviour: friction coefficient, wear local approach, experimentally determined and parameterised, ... The modelling needs an experimental verification – therefore the Research Group for Off-Road Machines performs a wide spectrum of tests on own test rigs for complete constructional units as well as for simple specimen. The competence shows itself also in the present key aspects of activity in this comprehensive area: simulation of wear for joints in chassis systems lifetime prediction of maintenance-free spherical plain bearings

The proof of service strength and reliability of mechanical components is one of the major competences of the Research Group for Off-Road Machines. Independent of a specific task, the assessment of static and dynamic strength is always based on an integrated concept starting with the identification and quantification of the relevant loads or load combinations, followed by the calculation of the resulting stresses and strains, and concluded with the comparison with the corresponding limit states. Applied tools and assessment methods: Application of rigid frame statics- and MBS-software tools for the determination of loads for components of complex mechanical systems and plant structures Modeling of beam-, area- and volume-shaped compo-nents Nominal and local stress concepts for the strength as-sessment; application of FEM-software for the determina-tion of local stresses as a result of mechanical and thermal loads Determination of limit states and execution of the proofs of competence according to current technical standards and specifications (e.g. FKM-Guidelines, DIN 743, EN 13001) Incorporation of effects of wear and corrosion in the assessment of service life of machine parts and plant components under high stress These tools and methods have been developed and success-fully applied within a long-time cooperation of the Research Group for Off-Road Machines with industry partners, the MPT incorporated society and several universities. These joint research projects are supported by the German Federal Min-istry of Education and Research (BMBF) and the German Federal Ministry of Economy (BMWi). Subject of these projects is the assessment of service strength and reliability of mechanical plant components used for the production of crude oil and gas: Strength assessment of machine parts and plant com¬ponents for multiphase transportation Derivation of parametrical models for the assessment of service life and reliability of components in order to cover varying installation sizes Consideration of limit states of service strength (e.g. static and fatigue limits) as well as limit states of service-ability (e.g. deformations, temperature limits) Determination of the influence of wear and corrosion on loads, stresses and limit states

Acoustics

CargoCap

Targeted development and optimization processes in the field of acoustics require an extensive system comprehension of the investigated machines which covers the complete mechanism of the noise generation including the excitation, the structure-born sound transmission and the airborne sound emission. In this context the Research Group for Off-Road Machines has developed a method for acoustic analysis especially for the assessment of highly complex machines and vehicles. The first step of this method is the construction of a global but nevertheless differentiated acoustic image of the machine in order to identify the relevant sound sources and the locations of sound emission. This image also allows for a characterization of the emission in the frequency range. The acquired system comprehension enables to derive targeted optimization and development approaches. This process is based on the classification of the sound sources in relation to their potential of optimization. Finally, in order to establish feasible solutions, not only the acoustic requirements but also the individual operating conditions are considered. Advantages of the method: systematic identification and assessment of the acoustic optimisation potential time-efficient development of feasible solutions for offroad machines specific suggestions for new product development cost reduction in the development process (e.g. less prototypes) parallel optimization and development process Research objectives on this field: Vibro-acoustic analysis and optimization of crawler-tracks: quantification of impact excitation determination of structure-born sound transmission and airborne sound emission development of approaches for the acoustic optimisation of crawler-tracks Acoustic optimization of driver cabins: experimentally supported analysis of the present acoustic state simulation-supported interior noise analysis of the cabin in order to derive optimized components and linkages of the components during the development process

The Idea: The research and development project CargoCap (www.cargocap.de) was founded by Prof. Dr.-Ing. Dietrich Stein at Ruhr- University Bochum in 1998. In the project team under his supervision, the technical departments have been working closely together with judicial and economical research partners. The intention of the project is the development of a system for fast, reliable and on-time transportation of goods through underground pipelines in densely populated urban areas. The Concept: Within the CargoCap system, individual transport capsules carry two euro-pallets through a network of pipes with a diameter of 1.6 m. The capsules are automated, electrically driven and track guided. At the stations, the loading and unloading of the euro-pallets is fully automated. A connection to street level exists only at these stations. They can be located in downtown areas or directly at the production line in factories. This contributes to the relief from ever growing traffic on the streets and improves transport quality in urban areas. The Model Test Track The model test track is the first realization of CargoCap and was designed and built by the Chair of Machine Parts and Materials Handling at the Ruhr-University Bochum. This test track in scale of 1:2 allows the research of electrical and mechanical aspects which is only possible during near-realistic operation provided by the model test track. Furthermore, the model test track gives an outlook at the suitability of CargoCap in a logistic environment. The Research Targets: Currently, the research team of the chair is working on proving the energy efficient operation of CargoCap with a special focus on the operation in pipes which results in a higher air drag. Therefore, one of the main research targets is to study how the formation of several capsules to distance controlled platoons, as well as optimizing the geometry, e.g. the capsule shape, effects their energy consumption. Furthermore, special control strategies for distance controlling of automated capsules are developed, compared and tested at the model test track. This research project is funded by the Deutsche Bundesstiftung Umwelt (one of Europe's largest foundations that promote innovative and exemplary environmental projects) for two years.