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  • 1.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Jansson, Anders
    Stockholm University, Applied Environmental Science, Stockholm, Sweden.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A pin-on-disc study of the rate of airborne wear particle emissions from railway braking materials2012In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 284, p. 18-29Article in journal (Refereed)
    Abstract [en]

    The current study investigates the characteristics of particles generated from the wear of braking materials, and provides an applicable index for measuring and comparing wear particle emissions. A pin-on-disc tribometer equipped with particle measurement instruments was used. The number concentration, size, morphology, and mass concentration of generated particles were investigated and reported for particles 10 nm-32 mu m in diameter. The particles were also collected on filters and investigated using EDS and SEM. The effects of wear mechanisms on particle morphology and changes in particle concentration are discussed. A new index, the airborne wear particle emission rate (AWPER), is suggested that could be used in legislation to control non-exhaust emissions from transport modes, particularly rail transport.

  • 2.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Larsson, Christina
    Bombardier Transportation Sweden AB, Västerås, Sweden.
    Jansson, Anders
    Stockholm University, Applied Environmental Science, Stockholm, Sweden.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A field test study of airborne wear particles from a running regional train2012In: IMechE, Part F: Journal of Rail and Rapid Transit, ISSN 0954-4097, Vol. 226, no 1, p. 95-109Article in journal (Refereed)
    Abstract [en]

    Inhalable airborne particles have inverse health affect. In railways, mechanical brakes, the wheel–rail contact, current collectors, ballast, sleepers, and masonry structures yield particulate matter. Field tests examined a Swedish track using a train instrumented with particle measurement devices, brake pad temperature sensors, and speed and brake sensors. The main objective of this field test was to study the characteristics of particles generated from disc brakes on a running train with an on-board measuring set-up.

    Two airborne particle sampling points were designated, one near a pad–rotor disc brake contact and a second under the frame, not near a mechanical brake or the wheel–rail contact; the numbers and size distributions of the particles detected were registered and evaluated under various conditions (e.g. activating/deactivating electrical brakes or negotiating curves). During braking, three speed/temperature-dependent particle peaks were identified in the fine region, representing particles 280 nm, 350 nm, and 600 nm in diameter. In the coarse region, a peak was discerned for particles 3–6 μm in diameter. Effects of brake pad temperature on particle size distribution were also investigated. Results indicate that the 280 nm peak increased with increasing temperature, and that electrical braking significantly reduced airborne particle numbers. FESEM images captured particles sizing down to 50 nm. The ICP-MS results indicated that Fe, Cu, Zn, Al, Ca, and Mg were the main elements constituting the particles.

     

  • 3.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Larsson, Christina
    Bombardier Transportation Sweden AB, Västerås, Sweden.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A study of airborne wear particles generated from organic railway brake pads and brake discs2011In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 273, no 1, p. 93-99Article in journal (Refereed)
    Abstract [en]

    Brake pads on wheel-mounted disc brakes are often used in rail transport due to their good thermal properties and robustness. During braking, both the disc and the pads are worn. This wear process generates particles that may become airborne and thus affect human health. The long term purpose of ‘Airborne particles in Rail transport’ project is to gain knowledge on the wear mechanisms in order to find means of controlling the number and size distribution of airborne particles. In this regard, a series of full-scale field tests and laboratory tests with a pin-on-disc machine have been conducted. The morphology and the matter of particles, along with their size distribution and concentration, have been studied. The validity of results from the pin-on-disc simulation has been verified by the field test results. Results show an ultra-fine peak for particles with a diameter size around 100 nm in diameter, a dominant fine peak for particles with a size of around 350 nm in diameter, and a coarse peak with a size of 3-7 μm in diameter. Materials such as iron, copper, aluminium, chromium, cobalt, antimony, and zinc have been detected in the nano-sized particles.

  • 4.
    Holmberg, Jan G.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Air quality in a reused submarine bunker2009In: Ventilation 2009, 2009Conference paper (Other academic)
  • 5.
    Jansson, Anders
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Airborne particle generation at metal wear2009Conference paper (Other academic)
  • 6. Jansson, Anders
    et al.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sundh, Jon
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Ultrafine Particle Formation from Wear2010In: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 9, no 1, p. 83-88Article in journal (Refereed)
    Abstract [en]

    Much attention is given to the consequences of airborne particles on human health and well-being. Wear is one source of airborne particles and contributions in the urban environments from wheel-to-rail contacts and disc brakes cannot be neglected. Traditionally, mechanical wear has been associated with the generation of particles of diameters of some microns. However, the research described has found ultrafine particle generation from wear processes. Particle generation from wear was measured under controlled laboratory conditions. The wear was created through sliding contact in a tribometer (type "pin-on-disc") with different materials and with different sliding velocities and pressures, to represent rail traffic and automobile disc braking. Particle concentrations and size distributions in the air were determined for particle diameters from 10 nm up to more than 10 mu m. For most materials and conditions three particle size modes were found: one at 50-100 nm, one at a few hundred nm and one at a few mu m particle diameter.

  • 7. Kutelia, E. R.
    et al.
    Gventsadze, D. I.
    Eristavil, B. G.
    Maisuradze, N. I.
    Tsurtsumia, O. O.
    Gventsadze, L. D.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    The tribological efficiency and the mechanism of action of nano-porous composition base brake lining materials2011In: International Congress on Advances in Applied Physics and Materials Science, 2011, p. 546-554Conference paper (Refereed)
    Abstract [en]

    Based on the comparative analysis of the experimental values determined for the tribological parameters for the three novel nano-porous composition base and two conventional brake lining materials while friction with the grey cast iron disc, it was shown the considerable high tribological efficiency of the novel nano-porous composition base lining materials in comparison with the conventional (from EU and USA market) brake lining materials. The explanation is given to the action mechanism of nano-porous composition base brake lining material and its tribological efficiency basing on the "triple phase" tribo-pair model.

  • 8.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Do Train Tunnels Need Ventilation Systems?2010In: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 9, no 1, p. 89-92Article in journal (Refereed)
    Abstract [en]

    A planned new train tunnel under the central parts of Stockholm was intended to be ventilated by natural ventilation and the movement of the trains. However, the amount of heat generated by the trains is so high that natural ventilation would give abnormal temperatures and velocities in the tunnel and at the stations. The heat adsorbed by the rock surrounding the tunnel can be neglected in comparison with the amount transported by air. Some of the problems with the ventilation system are described and also the problems with dust generation by the trains and the exposure to dust at the stations by the passengers. The final decision was to use glass walls at the stations to separate the ventilation for the tunnel from that for the stations.

  • 9.
    Olander, Lars
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Holmberg, Jan G.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Airborne particles in a large portrait collection2006In: Indoor Climate in Museums and Archives, 2006Conference paper (Other academic)
  • 10.
    Olofsson, Ulf
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    On the identification of wear modes and transitions using airborne wear particles2013In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 59, no SI, p. 104-113Article in journal (Refereed)
    Abstract [en]

    A novel test method was used to identify how contact conditions influence the wear modes and transitions for sliding steel-on-steel contacts. The test equipment was a pin-on-disc tribometer equipped with instruments for counting airborne particles. The results show that the dominant wear mode significantly influences the number of airborne particles generated from the contact. During mild wear few or no measurable airborne particles were generated. The transitional running-in process could also be identified by airborne particle measurement analysis.

  • 11.
    Olofsson, Ulf
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Jansson, Anders
    A Study of Airborne Wear Particles Generated From a Sliding Contact2009In: Journal of tribology, ISSN 0742-4787, E-ISSN 1528-8897, Vol. 131, no 4Article in journal (Refereed)
    Abstract [en]

    Recently, much attention has been paid to the influence of airborne particles in the atmosphere on human health. Sliding contacts are a significant source of airborne particles in urban environments. In this study airborne particles generated from a sliding steel-on-steel combination are studied using a pin-on-disk tribometer equipped with airborne-particle counting instrumentation. The instrumentation measured particles in size intervals from 0.01 mu m to 32 mu m. The result shows three particle size regimes with distinct number peaks: ultrafine particles with a size distribution peak around 0.08 mu m, fine particles with a peak around 0.35 mu m, and coarse particles with a peak around 2 or 4 mu m. Both the particle generation rate and the wear rate increase with increasing sliding velocity and contact pressure.

  • 12.
    Olofsson, Ulf
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Jansson, Anders
    Towards a model for the number of airborne particles generated from a sliding contact2009In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 267, no 12, p. 2252-2256Article in journal (Refereed)
    Abstract [en]

    Recently, much attention has been given to the influence of airborne particles in the atmosphere on human health. Sliding contacts are a significant source of airborne particles in urban environments. Airborne particles may be generated by disc brakes and wheel-rail contacts. This paper presents a new model for determining the number of airborne particles generated by a sliding contact. Previously presented data from a pin-on-disc tribometer equipped with airborne particle counting instrumentation was used to verify the model. The derived particle rate is proportional to the load for the ball bearing steel material evaluated. Furthermore, the model incorporates three particle regimes with distinct number peaks; one with ultra fine particles with a peak around 0.08 mu m, one with fine particles with a peak around 0.35 mu m and one with coarse particles with a peak around 2 mu m, that can be used to rank the number of generated particles from different material combinations and contact conditions.

  • 13.
    Olofsson, Ulf
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Jansson, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Airborne Wear Particles from Disc Brakes: A Comparison of Measurements from Cars, Test Stands and Material Tests2008Conference paper (Other academic)
  • 14.
    Sundh, Jon
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Wear rate testing in relation to airborne particles generated in a wheel-rail contact2009In: Lubrication science, ISSN 0954-0075, Vol. 21, no 4, p. 135-150Article in journal (Refereed)
    Abstract [en]

    This study examines the relationship between generated airborne particles and wear rate in the wheel-rail contact. The wheel-rail contact is experimentally simulated by using pin-on-disc testing to determine the difference in wear rate between selected contact conditions.

    Wear is discussed both in tribological terms and by using the wear categories prevalent in the railway industry, namely, mild, severe and catastrophic wear. The discussion is based on wear depth, the coefficient of friction, topographical measurements and measurements of airborne particles generated in the contact.

    The tests were performed under selected loading conditions representative of different contact conditions in a real wheel-rail contact. The results indicate that wear rates vary with the contact conditions arising from different types of triggered wear transitions. This is emphasised by the number and size of the airborne particles generated.

  • 15.
    Sundh, Jon
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Jansson, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Wear rate testing in relation with airborne particles generated in a wheel-rail contact2008Conference paper (Other academic)
  • 16.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Jansson, Anders
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    On Airborne Wear Particles Emissions ofCommercial Disc Brake Materials– A Pin on Disc Simulation2008Report (Other academic)
    Abstract [en]

    A novel test method was used to study the concentration and size distribution of airborne wear particles from disc brake materials. A pin-on-disc tribometer equipped with particle counting instruments was used as test equipment. Four different nonasbestoses-organic (NAO) linings for the U.S. market and four different low metallic linings for the EU market were tested against material from gray cast iron rotors. The result indicates that the low metallic linings are more aggressive to the rotor material then the NAO linings, resulting in higher amount of wear and concentrations of airborne wear particles. But, although there are variations in the measured particle concentrations, similar size distributions were obtained regardless of lining material.

  • 17.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Gventsadze, D.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Kutelia, E
    Gventsadze, L.
    Tsurtsumia, O.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A pin-on-disc investigation of nanoporous composite-based and conventional brake padmaterials focusing on airborne wear particles2011In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464Article in journal (Other academic)
  • 18.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Gventsadze, D.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Kutelia, E.
    Gventsadze, L.
    Tsurtsumia, O.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A pin-on-disc investigation of novel nanoporous composite-based and conventional brake pad materials focussing on airborne wear particles2011In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 44, no 12, p. 1838-1843Article in journal (Refereed)
    Abstract [en]

    Wear particles originating from disc brakes contribute to particulate concentration in the urban atmosphere. In this work novel nanoporous composite-based and conventional brake materials were tested against cast-iron discs in a modified pin-on-disc machine. During testing airborne wear particles were measured online and collected on filters, which were analysed using SEM and EDX. The morphology of airborne wear particles containing elements such as iron, oxygen, and copper is presented. These results show that two of the nanoporous materials generated 3-7 times less airborne wear particles than the conventional materials. Both the conventional and nanoporous materials displayed a bimodal number distribution.

  • 19.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Gventsadze, D
    Republic Dvali Institute of Machine Mechanics, Georgia.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Tsurtsumia, O
    Republic Center for Structure Researches of Georgian Technical University, Georgia.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A pin-on-disc study of nanoporous composite-based and conventional brake pad materials focussing on airborne wear particles2010Conference paper (Refereed)
  • 20.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A Pin-on-Disc Study Focusing on How Different Load Levels Affect the Concentration and Size Distribution of Airborne Wear Particles from the Disc Brake Materials2012In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 46, no 2, p. 195-204Article in journal (Refereed)
    Abstract [en]

    Airborne wear particles originating from disc brakes are one important contributor to the concentration of airborne particles in urban environments. It is therefore of interest to improve the knowledge of these particles. The purpose of this article is to investigate the concentration and size distribution of the airborne wear particles generated from the contact between a low-metallic pad material and a grey cast iron disc at different load levels. This is done on model level with a pin-on-disc machine that allows the cleanliness of the air surrounding the test specimens to be controlled, and thus the airborne portion of the wear particles to be studied separately. The concentration and size of airborne wear particles were measured online during testing with four particle instruments. In addition, airborne wear particles were collected on filters during the tests and afterward analysed using SEM. Trimodal size distributions with peaks around 280, 350 and 550 nm were registered during running-in for all load levels. After running-in bimodal size distributions with peaks around 350 and 550 nm were registered for all load levels with the exception of the highest load level where multimodal size distributions were registered. At the two highest load levels the concentration of ultrafine/fine particles showed an increase up to a factor hundred indicating a change in wear mechanism. SEM images show ultrafine, fine and coarse airborne wear particles.

  • 21.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Airborne Wear Particles Emissions ofCommercial Disc Brake Materials– Disc Brake Test Stand Simulations at LowContact Pressures and Rotors Pre-conditionedwith Rust2008Report (Other academic)
    Abstract [en]

    Most modern passenger cars have disc brakes on the front wheels, which unlike drum brakes are not sealed off to the ambient air. During braking, there is wear to both the rotor and the pads. This wear process generates particles, which may become airborne. A problem with measuring airborne wear particles in field tests is to distinguish them from the background noise. Therefore, a disc brake laboratory test stand that allows control of the cleanness of the surrounding air is used. With this test stand the number and size of the airborne wear particles from the pad to rotor contact can be measured online. In this technical report the results from two test series is presented. The first series were preformed at three brake cylinder pressure levels (1.2, 1.7 and 2.2 bar) and the rotors were pre-conditioned in a climate chamber with an oxide layer (e.g. rust). Ceramic NAO, NAO and low metallic type brake pads were tested. The second test series were conducted at three low brake cylinder pressure levels (0.1, 0.5 and 1 bar) with NAO and low metallic type brake pads, without any oxide layer. Promising results from the first test series indicate that this test stand can be used to study oxide layer removal from the rotor. The results are also promising for the ability to rank the number and size distribution from different pad rotor material combinations. The second test series shows that even at low pressures measurable levels of airborne particles are generated.

  • 22.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Size, Shape, and Elemental Composition of Airborne Wear Particles from Disc Brake Materials2010In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 38, no 1, p. 15-24Article in journal (Refereed)
    Abstract [en]

    During braking, both the rotor and pads experience wear, generating particles that may become airborne. In field tests, it is difficult to distinguish these particles from others in the surrounding environment, so it is preferable to use laboratory test stands to study the amount of airborne wear particles generated. The purpose of this work is to investigate the possibility of separate, capture, and analyze airborne wear particles generated by a disc brake in a disc brake assembly test stand. This test stand used allows the cleanliness of the air surrounding the test specimens to be controlled and thus the airborne portion of the wear particles to be studied separately. One pair each of low-metallic (LM) and non-asbestos organic (NAO) brake pads was tested against grey cast iron rotors. Before testing, the elemental contents of the brake materials were analyzed using glow discharge optical emission spectroscopy (GDOES). The concentration and size of airborne wear particles were measured online during testing. In addition, airborne wear particles were collected on filters during the tests and afterward analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The analyzed wear particles contained elements such as iron, titanium, zinc, barium, manganese, and copper. Both the low-metallic and non-asbestos organic type of brake pads tested display a bimodal size distribution with peaks at 280 and 350 nm. Most of the airborne particles generated have a diameter smaller than 2.5 mu m.

  • 23.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Jansson, Anders
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Airborne Wear Particles Emissions fromCommercial Disc Brake Materials– Passenger Car Field Test2008Report (Other academic)
    Abstract [en]

    Most modern passenger cars have disc brakes on the front wheels, which unlike drum brakes are not sealed off to the ambient air. During braking, there is wear to both the rotor and the pads.

    This wear process generates particles, which may become airborne. In field tests it is difficult to distinguish these particles from others in the surrounding environment. It may be preferable to use laboratory test stands where the cleanness of the surrounding air can be controlled. The validity of these test stands has to be verified by comparison with field tests and therefore a test series has been conducted. These tests were performed in Stockholm, Sweden, in urban traffic.

    Low metallic type brake pads and gray cast iron rotors were tested. The results indicate that this test methodology can be used to study the number and mass concentrations as well as size distributions of particles generated from car disc brakes. Overall, the measured mean particle number and mass diameters of the airborne particles were 0.39 μm and 1.5 μm, respectively.

  • 24.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    A pin-on-disc study of automotive disc brake materials focusing on airborne wear particles2010In: Journal of tribology, ISSN 0742-4787, E-ISSN 1528-8897Article in journal (Other academic)
  • 25.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Jansson, Anders
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A pin-on-disc simulation of airborne wear particles from disc brakes2010In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 268, no 5-6, p. 763-769Article in journal (Refereed)
    Abstract [en]

    A novel test method was used to study the concentration and size distribution of airborne wearparticles from disc brake materials. A pin-on-disc tribometer equipped with particle countinginstruments was used as test equipment. Material from four different non-asbestos organic(NAO) pads and four different low metallic (LM) pads were tested against material from greycast iron rotors. The results indicate that the low metallic pads cause more wear to the rotormaterial than the NAO pads, resulting in higher concentrations of airborne wear particles.Although there are differences in the measured particle concentrations, similar size distributionswere obtained. Independent of pad material, the characteristic particle number distributions ofairborne brake wear particles have maxima around 100, 280, 350, and 550 nm.

  • 26.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A disc brake test stand for measurement of airborne wear particles2009In: Lubrication Science, ISSN 0954-0075, Vol. 21, no 6, p. 241-252Article in journal (Refereed)
    Abstract [en]

    During braking, there is wear on both the rotor and the pads. This process generates particles that may becomeairborne. In field tests, it is difficult to distinguish these particles from others in the surrounding environment.Therefore, a laboratory test stand has been designed which allows control of the cleanliness of the surroundingair. The test stand consists of a front right brake assembly mounted in a sealed chamber. A braking load is appliedby a pneumatic system and the rotor, which has been pre-conditioned with a rust layer to simulate a car standingparked overnight in a wet environment, is driven by an electric motor. The number and size of airborne wearparticles are then measured. This experimental set-up has been verified by an initial test series performed at lowbraking loads. The results suggest that this test stand can be used to study rust layer removal from the rotor.

  • 27.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A disc brake test stand for measurement of airborne wear particles2008Conference paper (Refereed)
  • 28.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Jansson, Anders
    A pin-on-disc simulation of airborne wear particles from disc brakes2009Conference paper (Refereed)
  • 29.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Jansson, Anders
    Airborne wear particles from passenger car disc brakes: a comparison of measurements from field tests, a disc brake assembly test stand, and a pin-on-disc machine2010In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 224, no J2, p. 179-188Article in journal (Refereed)
    Abstract [en]

    Most modern passenger cars have disc brakes on the front wheels.Unlike drumbrakes,disc brakes are not sealed off from the ambient air. During braking, both the rotor and the padswear, and this wear process generates particles that may become airborne. In field tests it isdifficult to distinguish these particles from others in the environment. It is thus preferable toconduct tests using laboratory test stands where the cleanness of the surrounding air can becontrolled.However, the validity of results fromthese test stands should be verifiedbycomparisonwith field tests. This article presents a comparison of the number and volume distributions ofairborne wear particles as measured online in field tests, in a disc brake assembly test stand,and in a pin-on-disc machine. In all cases, grey cast iron rotors and low metallic pads weretested. A promising correlation between the three different test methods is shown. The numberandvolume-weighted mean particle diameter for all test methods is about 0.4 and 2–3μm,respectively.

1 - 29 of 29
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