Rene Boonen | KU Leuven (original) (raw)
Papers by Rene Boonen
Journal of Mechanical Design, Feb 1, 2008
This paper considers a class of high-speed airjet weaving machines that is characterized by exces... more This paper considers a class of high-speed airjet weaving machines that is characterized by excessive harness frame vibration, resulting in premature failure. This problem is tackled through addition of an auxiliary, input torque balancing mechanism: a centrifugal pendulum, of which the pendulum motion is imposed by an internal cam. While earlier work by the same authors focused on the design, optimization and robustness analysis of this mechanism, the current paper presents experimental results. The considered setup is an industrial weaving machineà blanc equipped with a centrifugal pendulum prototype. Below a critical speed, the prototype functions as predicted and significantly improves the machine dynamics: the drive speed fluctuation is reduced by a factor of 2.5 and the vibration level of the harness frames is halved. Above the critical speed, however, torsional resonance dominates the machine dynamics. This phenomenon is verified on simulation by extending the rigid-body setup model, on which the centrifugal pendulum design is based, with a torsional degree of freedom.
This paper reviews the design and validation of a novel bearing test rig developed at the KU Leuv... more This paper reviews the design and validation of a novel bearing test rig developed at the KU Leuven. The test rig allows multi-axial static and dynamic loading of a rolling element bearing. Different types and sizes of bearings can be mounted and loaded as if built into a real machine. The test rig will be used to analyse the effect of external dynamic loads on the lifetime of these bearings. The dynamics of the test rig were analysed during the design and validated af-terwards. It is proved that the bearings can be excited in the range from 25 to 440 Hz, free from resonances of the test rig. Also, several measures were taken to guarantee precise mea-surements of the bearing's axial, radial and tilt motion. In this way, accurately measuring the bearing behaviour while applying a fully controlled dynamic load is the key feature of the test rig.
When applying feedback control in active noise control, phase lag caused by transducer dynamics a... more When applying feedback control in active noise control, phase lag caused by transducer dynamics and time delay between microphones and noise sources limits the bandwidth of the controller considerably. The proposed method to increase stability is to compensate the phase lag by applying a Smith compensator. The compensator needs a model of the acoustic plant. As model, only the transducer dynamics are taken into account in this investigation. The compensator results in a considerable higher control bandwidth. Nevertheless, the demands on the transducer dynamics still remains high. The experiments demonstrate that phase lag can be partly compensated, but the poor transducer dynamics do not allow to close the control loop.
An active silencer to attenuate internal combustion engine exhaust noise is developed. The silenc... more An active silencer to attenuate internal combustion engine exhaust noise is developed. The silencer consists of an electrically controlled valve connected to a buffer volume. The pulsating flow from the engine is buffered in the volume and the valve resistance is continuously controlled such that only the mean flow passes to the atmosphere. This flow is free of fluctuations and consequently free of sound. The design of the active silencer is carried out using electrical analog circuits. First, the interaction between the active silencer and the engine will be studied using an analog circuit including the combustion engine and a linearized active silencer. Then, a detailed valve model is built in a separate electrical analog circuit. It includes the electrical, the mechanical and the flow-dynamic properties of the actuator valve. The actuator valve concept is then simulated, from which a prototype can be constructed. The active silencer has been tested on a cold engine simulator. Thi...
In this investigation, the acoustical impedance of an internal combustion engine is measured and ... more In this investigation, the acoustical impedance of an internal combustion engine is measured and simulated. The measurements are based on the two microphone transfer function method, which is described in the standard ISO/FDIS 10543-2. The method uses the transfer function between two microphones positioned on a waveguide connected to the impedance to be measured. Some improvements are proposed to this procedure, concerning the calibration of the measurement setup. New corrections are proposed to eliminate the speed of sound, the microphone locations and the the deviation between the microphone responses. The method is applied to measure the acoustical impedance of an engine. To prevent the engine to disturb the reflection coefficient during the measurements, the engine is run with an electric motor and the intake is sealed. The simulations are carried out using electrical analog circuits. The circuits are built by analyzing the geometrical data of the engine parts and the exhaust m...
Design projects have become omnipresent in engineering curricula, but are often of academic natur... more Design projects have become omnipresent in engineering curricula, but are often of academic nature. Nowadays, industrial partners prefer master students to work on industrial projects because prior technical knowledge is deemed indispensible. Such in-company trajects require a considerable coaching effort both from academic staff and from engineers in industry. The presented project illustrates how students with only basic engineering competences can work on industrial projects with minimum industrial support. The project is offered in the last year of the three-year bachelor program in electromechanical engineering. During this year the students' knowledge and competences are extended with electromechanical courses. The presented project encourages them to apply and extend their electromechanical knowledge. The assignment is to design an automated machine from scratch. Each year four industrial partners present their project to a group of about 100 students. The students organi...
Mechanical Systems and Signal Processing, 2015
ABSTRACT Precise prediction of the lifetime of rolling element bearings is a crucial step towards... more ABSTRACT Precise prediction of the lifetime of rolling element bearings is a crucial step towards a reliable design of many rotating machines. For bearings subjected to highly varying loads, recent research emphasises a strong reduction of the actual bearing lifetime w.r.t. the classically calculated bearing lifetime. This paper experimentally analyses the influence of external dynamic loads on the lifetime of rolling element bearings. A novel bearing test rig is introduced. The test rig is able to apply a fully controlled multi-axial static and dynamic load on a single test bearing. Also, different types and sizes of bearings can be tested. Two separate investigations are conducted. First, the behaviour of the lubricant film between the rolling elements and raceways is analysed. Increased metallic contact or breakdown of the film during dynamic excitation is investigated based on the measured electrical resistance through the bearing. The study shows that the lubricant film thickness follows the imposed variations of the load. Variations of the lubricant film thickness are similar to the variations when the magnitude of the static bearing load is changed. Second, wear of the raceway surfaces is analysed. Surface wear is investigated after a series of accelerated lifetime tests under high dynamic load. Due to sliding motion between asperities of the contacting surfaces in the bearing, polishing of the raceway honing structure occurs. This polishing is clearly observed on SEM images of the inner raceway after a test duration of only 0.5% of the calculated L10 life. Polishing wear of the surfaces, such as surface induced cracks and material delamination, is expected when the bearing is further exposed to the high dynamic load.
Lecture Notes in Mechanical Engineering, 2013
Volume 1: 23rd Biennial Conference on Mechanical Vibration and Noise, Parts A and B, 2011
A new type of suspension component with dry friction damping has been developed. It consist of an... more A new type of suspension component with dry friction damping has been developed. It consist of an Ω-shaped spring wire which ends can slip in their mountings. By positioning these components under 90 o around the suspended object, the suspension functions in all six degrees of freedom. The suspension compo-nent will be modelled as a series connection of a spring with a coulomb damper, which in turn is in parallel with a second spring. This model will be analysed using Hamilton's equations of motion to deal with the non-linear phenomena. An experimental setup has been realized whereupon the suspension components are validated using hammer impulses. The observed response is an efficiently damped sinusoidal motion which turns into an undamped sinusoid with small amplitude. In the spectrum, the resonance has been limited in magnitude to 10 dB and the isolation characteristic remaines −40 dB/decade equivalent to the undamped spring.
The determination of the fatigue life of a mechanical component subjected to cyclic multi-axial l... more The determination of the fatigue life of a mechanical component subjected to cyclic multi-axial loading is a critical and often time-consuming step in the design cycle of a product. It is generally accepted that conventional analytical tools and traditional safety factors are not sufficient for reliable fatigue life predictions of safety-critical components. Simulations with numerical models offer a solution, but the accuracy of these methods is limited. Therefore, physical experiments on full-scale prototypes are still necessary to validate analytical and numerical fatigue life estimates of safety-critical components. However, conventional fatigue life experiments require considerable time and resources and are therefore often limited, with larger uncertainty in the fatigue life predictions as a result. In this thesis, a methodology for accurate and accelerated fatigue experiments with limited complexity is proposed based on scaling laws for fatigue behaviour. The proposed method f...
A damping device, consisting of an annular tail-pipe, has been developed. It is applicable in sit... more A damping device, consisting of an annular tail-pipe, has been developed. It is applicable in situations wherein acoustic damping is required in combination with low flow resistance. Examples are ventilation systems, turbo-engines, intake and exhaust systems for internal combustion engines. The device consists of a central tube surrounded by a narrow slit. The central tube has an acoustic mass which impedance increases with frequency while the slit resistance remains constant. When the frequency has been increased sufficiently, a considerable part of the acoustic flow passes through the slit where it will be damped. In this way, acoustic energy can be dissipated while the flow experiances a low flow resistance. The acoustic properties of the device will be investigated using an electrical equivalent circuit. The impedance will be measured using an impedance measurement duct. The slit resistance will be identified and the damping mechanism will be investigated qualitatively. As resul...
53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference<BR>20th AIAA/ASME/AHS Adaptive Structures Conference<BR>14th AIAA, 2012
Journal of Mechanical Design, Feb 1, 2008
This paper considers a class of high-speed airjet weaving machines that is characterized by exces... more This paper considers a class of high-speed airjet weaving machines that is characterized by excessive harness frame vibration, resulting in premature failure. This problem is tackled through addition of an auxiliary, input torque balancing mechanism: a centrifugal pendulum, of which the pendulum motion is imposed by an internal cam. While earlier work by the same authors focused on the design, optimization and robustness analysis of this mechanism, the current paper presents experimental results. The considered setup is an industrial weaving machineà blanc equipped with a centrifugal pendulum prototype. Below a critical speed, the prototype functions as predicted and significantly improves the machine dynamics: the drive speed fluctuation is reduced by a factor of 2.5 and the vibration level of the harness frames is halved. Above the critical speed, however, torsional resonance dominates the machine dynamics. This phenomenon is verified on simulation by extending the rigid-body setup model, on which the centrifugal pendulum design is based, with a torsional degree of freedom.
This paper reviews the design and validation of a novel bearing test rig developed at the KU Leuv... more This paper reviews the design and validation of a novel bearing test rig developed at the KU Leuven. The test rig allows multi-axial static and dynamic loading of a rolling element bearing. Different types and sizes of bearings can be mounted and loaded as if built into a real machine. The test rig will be used to analyse the effect of external dynamic loads on the lifetime of these bearings. The dynamics of the test rig were analysed during the design and validated af-terwards. It is proved that the bearings can be excited in the range from 25 to 440 Hz, free from resonances of the test rig. Also, several measures were taken to guarantee precise mea-surements of the bearing's axial, radial and tilt motion. In this way, accurately measuring the bearing behaviour while applying a fully controlled dynamic load is the key feature of the test rig.
When applying feedback control in active noise control, phase lag caused by transducer dynamics a... more When applying feedback control in active noise control, phase lag caused by transducer dynamics and time delay between microphones and noise sources limits the bandwidth of the controller considerably. The proposed method to increase stability is to compensate the phase lag by applying a Smith compensator. The compensator needs a model of the acoustic plant. As model, only the transducer dynamics are taken into account in this investigation. The compensator results in a considerable higher control bandwidth. Nevertheless, the demands on the transducer dynamics still remains high. The experiments demonstrate that phase lag can be partly compensated, but the poor transducer dynamics do not allow to close the control loop.
An active silencer to attenuate internal combustion engine exhaust noise is developed. The silenc... more An active silencer to attenuate internal combustion engine exhaust noise is developed. The silencer consists of an electrically controlled valve connected to a buffer volume. The pulsating flow from the engine is buffered in the volume and the valve resistance is continuously controlled such that only the mean flow passes to the atmosphere. This flow is free of fluctuations and consequently free of sound. The design of the active silencer is carried out using electrical analog circuits. First, the interaction between the active silencer and the engine will be studied using an analog circuit including the combustion engine and a linearized active silencer. Then, a detailed valve model is built in a separate electrical analog circuit. It includes the electrical, the mechanical and the flow-dynamic properties of the actuator valve. The actuator valve concept is then simulated, from which a prototype can be constructed. The active silencer has been tested on a cold engine simulator. Thi...
In this investigation, the acoustical impedance of an internal combustion engine is measured and ... more In this investigation, the acoustical impedance of an internal combustion engine is measured and simulated. The measurements are based on the two microphone transfer function method, which is described in the standard ISO/FDIS 10543-2. The method uses the transfer function between two microphones positioned on a waveguide connected to the impedance to be measured. Some improvements are proposed to this procedure, concerning the calibration of the measurement setup. New corrections are proposed to eliminate the speed of sound, the microphone locations and the the deviation between the microphone responses. The method is applied to measure the acoustical impedance of an engine. To prevent the engine to disturb the reflection coefficient during the measurements, the engine is run with an electric motor and the intake is sealed. The simulations are carried out using electrical analog circuits. The circuits are built by analyzing the geometrical data of the engine parts and the exhaust m...
Design projects have become omnipresent in engineering curricula, but are often of academic natur... more Design projects have become omnipresent in engineering curricula, but are often of academic nature. Nowadays, industrial partners prefer master students to work on industrial projects because prior technical knowledge is deemed indispensible. Such in-company trajects require a considerable coaching effort both from academic staff and from engineers in industry. The presented project illustrates how students with only basic engineering competences can work on industrial projects with minimum industrial support. The project is offered in the last year of the three-year bachelor program in electromechanical engineering. During this year the students' knowledge and competences are extended with electromechanical courses. The presented project encourages them to apply and extend their electromechanical knowledge. The assignment is to design an automated machine from scratch. Each year four industrial partners present their project to a group of about 100 students. The students organi...
Mechanical Systems and Signal Processing, 2015
ABSTRACT Precise prediction of the lifetime of rolling element bearings is a crucial step towards... more ABSTRACT Precise prediction of the lifetime of rolling element bearings is a crucial step towards a reliable design of many rotating machines. For bearings subjected to highly varying loads, recent research emphasises a strong reduction of the actual bearing lifetime w.r.t. the classically calculated bearing lifetime. This paper experimentally analyses the influence of external dynamic loads on the lifetime of rolling element bearings. A novel bearing test rig is introduced. The test rig is able to apply a fully controlled multi-axial static and dynamic load on a single test bearing. Also, different types and sizes of bearings can be tested. Two separate investigations are conducted. First, the behaviour of the lubricant film between the rolling elements and raceways is analysed. Increased metallic contact or breakdown of the film during dynamic excitation is investigated based on the measured electrical resistance through the bearing. The study shows that the lubricant film thickness follows the imposed variations of the load. Variations of the lubricant film thickness are similar to the variations when the magnitude of the static bearing load is changed. Second, wear of the raceway surfaces is analysed. Surface wear is investigated after a series of accelerated lifetime tests under high dynamic load. Due to sliding motion between asperities of the contacting surfaces in the bearing, polishing of the raceway honing structure occurs. This polishing is clearly observed on SEM images of the inner raceway after a test duration of only 0.5% of the calculated L10 life. Polishing wear of the surfaces, such as surface induced cracks and material delamination, is expected when the bearing is further exposed to the high dynamic load.
Lecture Notes in Mechanical Engineering, 2013
Volume 1: 23rd Biennial Conference on Mechanical Vibration and Noise, Parts A and B, 2011
A new type of suspension component with dry friction damping has been developed. It consist of an... more A new type of suspension component with dry friction damping has been developed. It consist of an Ω-shaped spring wire which ends can slip in their mountings. By positioning these components under 90 o around the suspended object, the suspension functions in all six degrees of freedom. The suspension compo-nent will be modelled as a series connection of a spring with a coulomb damper, which in turn is in parallel with a second spring. This model will be analysed using Hamilton's equations of motion to deal with the non-linear phenomena. An experimental setup has been realized whereupon the suspension components are validated using hammer impulses. The observed response is an efficiently damped sinusoidal motion which turns into an undamped sinusoid with small amplitude. In the spectrum, the resonance has been limited in magnitude to 10 dB and the isolation characteristic remaines −40 dB/decade equivalent to the undamped spring.
The determination of the fatigue life of a mechanical component subjected to cyclic multi-axial l... more The determination of the fatigue life of a mechanical component subjected to cyclic multi-axial loading is a critical and often time-consuming step in the design cycle of a product. It is generally accepted that conventional analytical tools and traditional safety factors are not sufficient for reliable fatigue life predictions of safety-critical components. Simulations with numerical models offer a solution, but the accuracy of these methods is limited. Therefore, physical experiments on full-scale prototypes are still necessary to validate analytical and numerical fatigue life estimates of safety-critical components. However, conventional fatigue life experiments require considerable time and resources and are therefore often limited, with larger uncertainty in the fatigue life predictions as a result. In this thesis, a methodology for accurate and accelerated fatigue experiments with limited complexity is proposed based on scaling laws for fatigue behaviour. The proposed method f...
A damping device, consisting of an annular tail-pipe, has been developed. It is applicable in sit... more A damping device, consisting of an annular tail-pipe, has been developed. It is applicable in situations wherein acoustic damping is required in combination with low flow resistance. Examples are ventilation systems, turbo-engines, intake and exhaust systems for internal combustion engines. The device consists of a central tube surrounded by a narrow slit. The central tube has an acoustic mass which impedance increases with frequency while the slit resistance remains constant. When the frequency has been increased sufficiently, a considerable part of the acoustic flow passes through the slit where it will be damped. In this way, acoustic energy can be dissipated while the flow experiances a low flow resistance. The acoustic properties of the device will be investigated using an electrical equivalent circuit. The impedance will be measured using an impedance measurement duct. The slit resistance will be identified and the damping mechanism will be investigated qualitatively. As resul...
53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference<BR>20th AIAA/ASME/AHS Adaptive Structures Conference<BR>14th AIAA, 2012