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Keywords: Monte-Carlo simulation, interval analysis, fuzzy analysis, truss structure, safety factor, uncertainty, probability of failure.

Summary

Load bearing mechanical structures like trusses face uncertainty in loading along with uncertainty in stress and strength due to uncertainty in their development, production and usage. According to the working hypothesis of the German Collaborative Research Centre SFB 805, uncertainty occurs in processes that are not, or only partial deterministic, and can only be controlled in processes. The authors classify and compare different methodical approaches to describe and to evaluate uncertainty in the development phase of three simple two-dimensional linear mathematical truss structure models in a consistent way. The truss structures are assumed to be mounted statically determined. They are each loaded by a vertical static force at a similar node. The criteria to compare the methodical approaches for uncertainty analysis are the limit load condition in one of the columns in the truss structure due to that load. For that, the authors distinguish between stochastic and non-stochastic or, respectively, probabilistic and non-probabilistic evaluation methods, depending on the quality of information of the internal system properties such as geometry and material, and external properties such as magnitude and direction of loading. As a probabilistic approach, direct Monte-Carlo simulation with full sample sets of internal and external property values are conducted exemplarily. Furthermore, the relation between the number of columns in a truss structure and the number of samples through the criteria of convergence is presented. Examples of interval and fuzzy analysis will give information about non-probabilistic uncertainty. The effectiveness and confidence intervals of the different methods will be evaluated by means of the uncertain limit load condition in one column of the truss structure due to uncertainty in internal and external system properties. Additionally, uncertainty of the safety factor for the three trusses is analysed by varying the radii of the columns and by evaluating the probability of failure.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 109 PROCEEDINGS OF THE FOURTH INTERNATIONAL CONFERENCE ON SOFT COMPUTING TECHNOLOGY IN CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING Edited by: Y. Tsompanakis, J. Kruis and B.H.V. Topping Paper 26 Comparison of Methodical Approaches to Describe and Evaluate Uncertainty in the Load-Bearing Capacity of a Truss Structure C.M. Melzer¹, R. Platz² and T. Melz^1,2 ¹System Reliability and Machine Acoustics, Technische Universität Darmstadt, Germany ²Fraunhofer Institute for Structural Durability and System Reliability, Darmstadt, Germany doi:10.4203/ccp.109.26 purchase the full-text of this paper Full Bibliographic Reference for this paper C.M. Melzer, R. Platz, T. Melz, "Comparison of Methodical Approaches to Describe and Evaluate Uncertainty in the Load-Bearing Capacity of a Truss Structure", in Y. Tsompanakis, J. Kruis, B.H.V. Topping, (Editors), "Proceedings of the Fourth International Conference on Soft Computing Technology in Civil, Structural and Environmental Engineering", Civil-Comp Press, Stirlingshire, UK, Paper 26, 2015. doi:10.4203/ccp.109.26 Keywords: Monte-Carlo simulation, interval analysis, fuzzy analysis, truss structure, safety factor, uncertainty, probability of failure. Summary Load bearing mechanical structures like trusses face uncertainty in loading along with uncertainty in stress and strength due to uncertainty in their development, production and usage. According to the working hypothesis of the German Collaborative Research Centre SFB 805, uncertainty occurs in processes that are not, or only partial deterministic, and can only be controlled in processes. The authors classify and compare different methodical approaches to describe and to evaluate uncertainty in the development phase of three simple two-dimensional linear mathematical truss structure models in a consistent way. The truss structures are assumed to be mounted statically determined. They are each loaded by a vertical static force at a similar node. The criteria to compare the methodical approaches for uncertainty analysis are the limit load condition in one of the columns in the truss structure due to that load. For that, the authors distinguish between stochastic and non-stochastic or, respectively, probabilistic and non-probabilistic evaluation methods, depending on the quality of information of the internal system properties such as geometry and material, and external properties such as magnitude and direction of loading. As a probabilistic approach, direct Monte-Carlo simulation with full sample sets of internal and external property values are conducted exemplarily. Furthermore, the relation between the number of columns in a truss structure and the number of samples through the criteria of convergence is presented. Examples of interval and fuzzy analysis will give information about non-probabilistic uncertainty. The effectiveness and confidence intervals of the different methods will be evaluated by means of the uncertain limit load condition in one column of the truss structure due to uncertainty in internal and external system properties. Additionally, uncertainty of the safety factor for the three trusses is analysed by varying the radii of the columns and by evaluating the probability of failure. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £50 +P&P)
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