Probabilistic analysis of damage accumulation with special regard to building structures stressed by collectives with higher number of cycles

• Applicant: Professor Dr.-Ing. Karsten Geißler
• Subject Area: Structural Engineering, Building Informatics and Construction Operation
• Term: from 2014 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 252979423

The variance oft the real damage sum in the case of stress collectives depends on the variance of material and fabrication properties and additional on the accuracy of the used Miner-rule for determination of damage. At the field of civil engineering a limit damage sum of 1.0 is still usual, at other fields other limit damage sums are usual. A complete probabilistic concept of the damage accumulation under stress collectives, from the variance of Woehler-curve to the resulting variance of the limit damage (D_tat), additional depending on the used Miner-Rule, was developed at the former DFG-project. At this project the resulting safety elements were analyzed by systematic calculations for a small range of influence parameters, because of test results were only for some collectives available. Based on the results following further necessary aspects were recognized. It’s necessary to analyze the typical parameters of structural engineering as bridges and wind turbine constructions, especially for collectives with a low relation of the maximum to the threshold stress value (∆σ_max/∆σ_D), with a high number H ̅ and also other stress relations (R ̅ between 0 and 0.5). At the result other design values of the main influence parameters were expecting, additional explicit depending on the used Miner-rule. Furthermore it is focused to analyze the influence of the targeted safety index (ß_tar = 1,5…3,8) to the design values. Following sub-goals are provided: - Fatigue tests with collectives typical for structural engineering with regard to the accuracy of life time predictions, - Extension of the results within the concept for probabilistic damage calculation with special regard to the parameters which are typical for structural engineering, - Systematic analyze of the influence of the targeted safety index to the design values.

• DFG Programme: Research Grants