PSI - Issue 42

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Procedia Structural Integrity 42 (2022) 687–693

23 European Conference on Fracture - ECF23 Strength calculations and fatigue tests of welded bus bodywork nodes Miloslav Kepka a , Miloslav Kepka jr. a , Radovan Minich a a Regional Technological Institute, Faculty of Mechanical Engineering, University of West Bohemia, Univerzitni 2732/8, 301 00 Pilsen, Czech Republic a a a i l l i l I tit t , lt f i l i i , i it f t i , i it i / , il , li

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 Abstract Laboratory fatigue life tests were performed for several structural variants of welded nodes of thin-walled profiles of a bus bodywork. The laboratory fatigue tests were supported by FEM calculation and strain gauge experimental stress analysis. S-N curves were evaluated and used to predict the fatigue life of these structural nodes under random operational loading of the vehicle bodywork. Measuring systems for on-line monitoring of stresses in the vehicle bodywork have been developed and applied. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 Keywords: welded bus bodywork node; laboratory fatigue test; FEM calculation; stress spectrum; on-line measurement; fatigue life calculation. 1. Introduction The methodology for solving the service strength and fatigue life of city buses and trolleybuses has already been presented to the professional public several times. For the first time by Kepka and Rehor (1992). Most recently, Spirk and Kepka (2015) were discussed in relation to development of battery-powered buses. A comprehensive approach to evaluating the service strength of a trolleybus body, including practical examples, was recently published by Kepka et al. (2020). The development of a new bus structure involves both computational and experimental activities: CAD, MBS, FEM calculations, stand test and measurement with bus prototypes. The methodology is highly complex. The methodology uses the advantages of virtual prototyping in combination with various tests in laboratories and testing of vehicles on real roads and test tracks including special roads on test polygons. The final activity is the fatigue life assessment. In order to calculate fatigue service life of structures and their parts operating under cyclic loads, one needs the following data: information on their fatigue strength and information on their service loads. In high-cycle fatigue scenarios, the main input data includes: S-N curves and service stress spectra for major operating modes. This input information must apply to the same (critical) cross-section of the evaluated component. It is usually found by t ti li t t l t t l i t l t i ll il . l t ti t t t l l ti t i i t l t l i . l t t i t t ti li t t t l ti l l i t i l . i t li it i t i t i l l li . t . li l i . . This is an open access article under the CC B li tt :// ti . /li / / . / i i ilit t : l r ; l r t r f ti t t; l l ti ; tr tr ; -li r t; f ti lif l l ti . . i t l l i t i t t ti li it t ll l t t t i l li l ti . t i t ti . t tl , i i i l ti t l t tt . i t l ti t i t t t ll , i l i ti l l , tl li t l. . l t t t i l t t ti l i t l ti iti : , , l l ti , t t t t it t t . t l i i l l . t l t t i t l t t i i i ti it i t t i l t i t ti i l l t t t i l i i l t t l . i l ti it i t ti li t. t l l t ti i li t t t i t ti li l , t ll i t : i ti t i ti t t i ti t i i l . i l ti i , t i i t t i l : i t t j ti . i i t i ti t l t t iti l ti t l t t. t i ll

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 l i r . . i i rti l r t - - li ( tt :// r ti . r /li / - - / . /) i i ilit t - t r . li

2452-3216 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.087