| 1. |
- Bengtsson, Anders, et al.
(författare)
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Fatigue Damage Uncertainty
- 2009
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Ingår i: Robust Design Methodology for Reliability. - Chichester, UK : John Wiley & Sons, Ltd. - 9780470713945 ; , s. 151-171
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Bengtsson, Anders, et al.
(författare)
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Uncertainty of estimated rainflow damage for random loads
- 2009
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Ingår i: Marine Structures. - : Elsevier BV. - 0951-8339 .- 1873-4170. ; 22:2, s. 261-274
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Tidskriftsartikel (refereegranskat)abstract
- One way to assess the uncertainty in fatigue damage analysis is to use a so-called safety index. In the computation of such an index the coefficient of variation for the accumulated damage is needed. Employing the rainflow cycle count method for fatigue damage leads to, in most cases, complicated calculations. Here we present a new and simplified method to estimate the coefficient of variation for the accumulated damage when only one sample path of the load is available. Non-stationary, slowly changing, Gaussian loads are given special attention. The approach is illustrated by means of stationary Gaussian loads with nine different spectra, a measured non-Gaussian load, a skewed load and the wave load accumulated during one year in a "seasonally changing environment"
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| 3. |
- Bogsjö, Klas
(författare)
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Development of analysis tools and stochastic models of road profiles regarding their influence on heavy vehicle fatigue
- 2006
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 1744-5159 .- 0042-3114. ; 44:S1, s. 780-790
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Tidskriftsartikel (refereegranskat)abstract
- Road profiles are analyzed with focus on road characteristics essential for heavy vehicle fatigue assessment. Road profile measurements indicate that roads contain short sections with above-average irregularity. Such rough sections are shown to cause most of the vehicle fatigue damage. An algorithm using a spatial-frequency description is developed to automatically identify rough sections. On the basis of the analysis, a new stochastic road model, with randomly placed and randomly shaped irregularities, is proposed.
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| 4. |
- Bogsjö, Klas
(författare)
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Evaluation of stochastic models of parallel road tracks
- 2007
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Ingår i: Probabilistic Engineering Mechanics. - : Elsevier BV. - 0266-8920. ; 22:4, s. 362-370
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Tidskriftsartikel (refereegranskat)abstract
- In road roughness literature different stochastic models of parallel road tracks are suggested. A new method is proposed to evaluate their accuracy, by comparison of measured parallel tracks and synthetic parallel tracks, realized from a stochastic model. A model is judged accurate if synthetic and measured roads induce a similar amount of fatigue damage to a vehicle. A lack-of-fit measure is assigned to the evaluated models, facilitating a quick and simple comparison. The uncertainty of the vehicle fatigue indicated for the measured profile is considered in the definition of the lack-of-fit measure. A bootstrap technique is applied to estimate the uncertainty. (c) 2007 Elsevier Ltd. All rights reserved.
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| 5. |
- Bogsjö, Klas, et al.
(författare)
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Fatigue relevant road surface statistics
- 2003
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Ingår i: Vehicle System Dynamics. - 0042-3114. ; 41, s. 724-733
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Konferensbidrag (refereegranskat)abstract
- Road roughness is a major source of vehicle fatigue. To improve the understanding of vehicle durability, statistical methods are applied to characterise measured road profiles. Different statistical road models are used to generate corresponding synthetic road profiles. Vehicle fatigue is assessed utilising a simple quarter-vehicle model in combination with the Palmgren-Miner damage hypothesis, Basquin's relation and Rainflow counting. Several road realisations (Monte-Carlo simulation) provide an estimate of the expected fatigue damage. The results suggest that actual roads cause more damage than synthetic Gaussian roads, possibly due to occasional road transients (bumps and holes), causing large loads on the vehicle. Thus, a road model being the sum of Gaussian 'noise' and transient events is suggested
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| 6. |
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| 7. |
- Bogsjö, Klas, et al.
(författare)
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Models for road surface roughness
- 2012
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 50:5, s. 725-747
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on the statistical description and analysis of road surface irregularities that are essential for heavy-vehicle fatigue assessment. Three new road profile models are proposed: a homogenous Laplace moving average process, a non-homogenous Laplace process and a hybrid model that combines Gaussian and Laplace modelling. These are compared with the classical homogenous Gaussian process as well as with the non-homogenous Gaussian model that represents the road surface as a homogenous Gaussian process with Motor Industry Research Association spectrum enhanced by randomly placed and shaped irregularities. The five models are fitted to eight measured road surfaces and their accuracy and efficiency are discussed.
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| 8. |
- Bogsjö, Klas
(författare)
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Road profile statistics relevant for vehicle fatigue
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Road profiles are studied from a vehicle fatigue point of view. A wide range of roads have been measured: from smooth motorways to very rough gravel roads. It is observed that the road profiles consist of irregular sections, which makes the stationary Gaussian model unsuitable (Paper A). In Paper B, a method for automatic identification of such irregularities is presented. It is verified that the irregular sections cause the major part of the fatigue damage induced in vehicles. Based on this result, a new single track model is proposed, which includes randomly shaped and located irregularities. In Paper C, an evaluation method of single track models is proposed. This evaluation method is extended to models of parallel tracks in Paper D. A new "parallel tracks" model is proposed and evaluated accordingly. In Paper E, the coherence between the parallel road tracks is studied. A simple one-parametric model is proposed for the coherence. In Paper F a new theoretical method to compute the expected vehicle fatigue damage caused by road irregularities is presented.
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| 9. |
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| 10. |
- Bogsjö, Klas, et al.
(författare)
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Vehicle fatigue damage caused by road irregularities
- 2009
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Ingår i: Fatigue and Fracture of Engineering Materials and Structures. - : Wiley. - 8756-758X .- 1460-2695. ; 32:5, s. 391-402
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Tidskriftsartikel (refereegranskat)abstract
- Road roughness causes fatigue-inducing loads in travelling vehicles. Road sections with a high degree of roughness are of special interest because these have a significant impact on vehicle's fatigue life. This study is focused on the statistical description and analysis of vehicle damage caused by irregularities. Standard statistical analysis tools are not straightforwardly applicable because of the non-stationary property of the irregularities. However, it is found that the road irregularities' influence on vehicles can be accurately described using a 'local' narrow-band approximation of the fatigue damage intensity. © 2009 Blackwell Publishing.
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