Applied Numerical Analysis. By C.F. Gerald. Pp. xii, 340. £3·60. 1970. (Addison-Wesley.)

In this paper, a new framework for model order reduction of LTI parametric systems is introduced. After generating and reducing several local original models in the parameter space, a parametric reduced-order model is calculated by interpolating the system matrices of the local reduced models. The main task is to find compatible system representations with optimal interpolation properties. Two approaches for this purpose are presented together with several numerical simulations.

Parametric Model Order Reduction by Matrix Interpolation

Design, modelling, simulation and integration of cyber physical systems

Machine tool's productivity is a function of the dynamic response between the spindle nose and table, which varies as a function of drive positions within the machine work volume. The position-dependent structural dynamics results in varying stability of the machine. This paper presents a computationally efficient methodology to evaluate and improve dynamic performance of a machine tool at the design stage. An efficient position-dependent multibody dynamic model of a machine tool is developed based on reduced model substructural synthesis. The experimentally validated reduced machine model simulates position-dependent behavior with significantly less computational effort than commonly used full order Finite Element models. The proposed modeling strategy is used to identify weak components of an experimental machine, which limit the productivity due to chatter. The identified weak machine component is modified and the complete dynamics are rapidly analyzed by virtually re-assembling the machine using reduced order models. Optimal design modifications are shown to increase productivity by ∼25%. The proposed method can be used for efficient simulation of structural dynamics, stability assessment as well as interactions of the CNC and cutting process with the machine tool structure in a virtual environment.

Rapid evaluation and optimization of machine tools with position-dependent stability

Mechatronics modeling and vibration analysis of a 2-DOF parallel manipulator in a 5-DOF hybrid machine tool

Measurement and analysis of rolling tire vibrations

This paper presents the measurement and analysis of rolling tire vibrations due to road impact excitations, such as from cobbled roads, junctions between concrete road surface plates, railroad crossings. Vibrations of the tire surface due to road impact excitations cause noise radiation in the frequency band typically below 500 Hz. Tire vibration measurements with a laser Doppler vibrometer are performed on a test set-up based on a tire-on-tire principle which allows highly repetitive and controllable impact excitation tests under various realistic operating conditions. The influence on the measured velocity of random noise, cross sensitivity and alignment errors is discussed. An operational modal analysis technique is applied on sequential vibration measurements to characterise the dynamic behaviour of the rolling tire. Comparison between the operational modal parameters of the rolling tire and the modal parameters of the non-rolling tire allows an assessment of the changes in dynamic behaviour due to rolling.

Wim Desmet

Papers

Measurement and analysis of rolling tire vibrations

Measurement and analysis of rolling tire vibrations

Integrated structure and control design for mechatronic systems with configuration-dependent dynamics

Concurrent mechatronic design approach for active control of cavity noise

Computer-aided integrated design for machines with varying dynamics