TY - JOUR A1 - Kowitz, Astrid A1 - Wu, Cheng-Chieh A1 - Helmerich, Rosemarie A1 - Hille, Falk A1 - Kadoke, Daniel A1 - Gründer, Klaus-Peter A1 - Hauser, S. A1 - Schwarzinger, H. ED - Bland, S. T1 - Impact on a micro-reinforced UHPC: Experimental studies versus numerical modeling N2 - Within the presented research project, experimental and numerical investigations were performed to develop a thin-shelled, modular, mobile element system made of a micro-reinforced ultra-high-performance ductile concrete (DUCON®). Material parameters were experimentally determined to adapt the material model within the numerical analysis applying the Drucker-Prager relationship. Afterwards, for validation of the numerical models, quasi-static and high-velocity impact tests were performed on plate-like structures. Finally, a suitable geometry of transportable barrier elements will be designed, which provides a maximum of resistance against impact by a minimum of weight and a maximum of mobility. KW - UHPC KW - Impact KW - DUCON® KW - Quasi-static and dynamic tests KW - Micro-reinforcement KW - Ductility KW - Mobile elements KW - Numerical modeling KW - Stereo photogrammetry KW - Compressive strength KW - E-modulus PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S2214785319305115?dgcid=author U6 - https://doi.org/10.1016/j.matpr.2019.03.152 SN - 2214-7853 VL - 12 IS - 2 SP - 474 EP - 483 PB - Elsevier Ltd CY - Amsterdam AN - OPUS4-48181 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bhuyan, Md Delwar Hossain A1 - Le Touz, N. A1 - Gautier, G. A1 - Döhler, M. A1 - Hille, Falk A1 - Dumoulin, J. A1 - Mevel, L. T1 - Load vector based damage localization with rejection of the temperature effect N2 - The Stochastic Dynamic Damage Locating Vector (SDDLV) approach is a vibration-based damage localization method based on both a finite element model of a structure and modal parameters estimated from output-only measurements in the damage and reference states. A statistical version of the Approach takes into account the inherent uncertainty due to noisy measurement data. In this paper, the effect of temperature fluctuations on the performance of the method is analyzed in a model-based approach using a finite element model with temperature dependent parameters. Robust damage localization is carried out by rejecting the temperature influence on the identified modal parameters in the damaged state. The algorithm is illustrated on a simulated structure. T2 - 8. International Operational Modal Analysis Conference CY - Kopenhagen, Denmark DA - 12. Mai 2019 KW - SDDLV KW - Load vector KW - Temperature rejection KW - Statistical evaluation PY - 2019 SP - 1 EP - 10 AN - OPUS4-48182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bhuyan, Md Delwar Hossain A1 - Döhler, M. A1 - Lecieux, Y. A1 - Lupi, C. A1 - Thomas, J.-C. A1 - Schoefs, F. A1 - Hille, Falk A1 - Mevel, L. T1 - Statistical subspace based damage localization on Saint-Nazaire bridge mock-up N2 - The subject of damage localization is an important issue for Structural Health Monitoring (SHM) particularly in mechanical or civil structures under ambient excitation. In this paper, the statistical subspacebased damage localization method has been applied on a benchmark application, namely a 1/200 scale model of the Saint-Nazaire Bridge, which is a cable-stayed bridge located on the Loire River near the river’s mouth. The employed damage localization method combines data-driven features with physical parameter information from a finite element model in statistical tests, avoiding typical ill-conditioning problems of FE model updating. Damage is introduced in the mockup for cable failures on some of the 72 cables. The purpose of the experiment is to assess the capability of damage assessment methods to find a cable failure. T2 - 8. International Operational Modal Analysis Conference CY - Kopenhagen, Denmark DA - 12. Mai 2019 KW - Damage localization KW - Cable-stayed bridge KW - Cable failure KW - Structural health monitoring PY - 2019 SP - 1 EP - 9 AN - OPUS4-48183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Viefhues, Eva A1 - Döhler, M. A1 - Zhang, Q. A1 - Hille, Falk A1 - Mevel, L. T1 - Subspace-based Damage Detection with Rejection of the Temperature Effect and Uncertainty in the Reference N2 - Temperature variation can be a nuisance that perturbs vibration based structural health monitoring (SHM) approaches for civil engineering structures. In this paper, temperature affected vibration data is evaluated within a stochastic damage detection framework, which relies on a null space based residual. Besides two existing temperature rejection approaches – building a reference state from an averaging method or a piecewise method – a new approach is proposed, using model interpolation. In this approach, a general reference model is obtained from data in the reference state at several known reference temperatures. Then, for a particular tested temperature, a local reference model is derived from the general reference model. Thus, a well fitting reference null space for the formulation of a residual is available when new data is tested for damage detection at an arbitrary temperature. Particular attention is paid to the computation of the residual covariance, taking into account the uncertainty related to the null space matrix estimate. This improves the test performance, contrary to prior methods, for local and global damages, resulting in a higher probability of detection (PoD) for the new interpolation approach compared to previous approaches. T2 - International Operational Modal Analysis Conference CY - Copenhagen, Danmark DA - 13.05.2019 KW - Uncertainty KW - Statistical method KW - Subspace-based method KW - Temperature rejection KW - Model interpolation PY - 2019 SP - 1 EP - 11 AN - OPUS4-48240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bhuyan, Md Delwar Hossain A1 - Le Touz, N. A1 - Gautier, G. A1 - Döhler, M. A1 - Hille, Falk A1 - Dumoulin, J. A1 - Mevel, L. T1 - Load Vector Based Damage Localization with Rejection of the Temperature Effect N2 - The Stochastic Dynamic Damage Locating Vector (SDDLV) approach is a vibration-based damage localization method based on both a finite element model of a structure and modal parameters estimated from output-only measurements in the damage and reference states. A statistical version of the Approach takes into account the inherent uncertainty due to noisy measurement data. In this paper, the effect of temperature fluctuations on the performance of the method is analyzed in a model-based approach using a finite element model with temperature dependent parameters. Robust damage localization is carried out by rejecting the temperature influence on the identified modal parameters in the damaged state. The algorithm is illustrated on a simulated structure. T2 - International Operational Modal Analysis Conference CY - Copenhagen, Danmark DA - 13.05.2019 KW - Statistical evaluation KW - Damage localization KW - SDDLV KW - Load vector KW - Temperature rejection PY - 2019 SP - 1 EP - 10 AN - OPUS4-48241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bhuyan, Md Delwar Hossain A1 - Döhler, M. A1 - Lecieux, Y. A1 - Lupi, C. A1 - Thomas, J. A1 - Schoefs, F. A1 - Hille, Falk A1 - Mevel, L. T1 - Statistical Subspace-based Damage Localization on Saint-Nazaire Bridge Mock-Up N2 - The subject of damage localization is an important issue for Structural Health Monitoring (SHM) particularly in mechanical or civil structures under ambient excitation. In this paper, the statistical subspacebased damage localization method has been applied on a benchmark application, namely a 1/200 scale model of the Saint-Nazaire Bridge, which is a cable-stayed bridge located on the Loire River near the river’s mouth. The employed damage localization method combines data-driven features with physical parameter information from a finite element model in statistical tests, avoiding typical ill-conditioning problems of FE model updating. Damage is introduced in the mockup for cable failures on some of the 72 cables. The purpose of the experiment is to assess the capability of damage assessment methods to find a cable failure. T2 - International Operational Modal Analysis Conference CY - Copenhagen, Danmark DA - 13.05.2019 KW - Structural health monitoring KW - Damage localization KW - Cable-stayed bridge KW - Cable failure PY - 2019 SP - 1 EP - 9 AN - OPUS4-48243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias A1 - Bhuyan, Delwar A1 - Hille, Falk A1 - Viefhues, Eva A1 - Döhler, M. A1 - Mevel, L. ED - Zingoni, Alphose T1 - Impact of environmental based effects on SHM strategies N2 - Environmental based perturbations influence significantly the ability to identify structural dam-age in Structural Health Monitoring. Strategies are needed to classify such effects and consider them appropri-ately in SHM. It has to be considered if seasonal effects just mask the structural response or if temperature itself correlates to a weakening of the structure. Various methods have been developed and analyzed to separate environmental based effects from damage induced changes in the measures. Generally, two main approaches have emerged from research activity in this fields: (a) statistics-based tools analyzing patterns in the data or in computed parameters and (b) methods, utilizing the structural model of the bridge considering environmental as well as damage-based changes of stiffness values. With the background of increasing affordability of sensing and computing technology, effort should be made to increase sensitivity, reliability and robustness of proce-dures, separating environmental from damage caused changes in SHM measures. The contribution describes an attempt to evaluate both general strategies, their advantages and drawbacks. In addition, two vibration moni-toring procedures are introduced, allowing for temperature-based perturbations of the monitoring data. T2 - SEMC 2019 CY - Cape Town, South Africa DA - 02.09.2019 KW - SHM environmental bridges PY - 2019 SN - 978-1-138-38696-9 SN - 978-0-429-42650-6 U6 - https://doi.org/10.1201/9780429426506 SP - Paper 324, 1 EP - Paper 324, 6 PB - CRC Press CY - Boca Raton AN - OPUS4-49167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nerger, Deborah A1 - Hille, Falk A1 - Moosavi, Robabeh A1 - Grunwald, Marcel A1 - Redmer, Bernhard A1 - Kühn, T. A1 - Hering, M. A1 - Bracklow, F. T1 - Improved tomographic investigation for impact damage characterization N2 - Reinforced concrete (RC) is used as structural material in most diverse civil engineering applications. For the variability of its physical properties it is still an engineering challenge to meet all necessary requirements for the prediction of dynamic effects under impact loading. In this paper, investigations are shown within the scope of quantifying and evaluating the damage caused by an impact. The experimental investigations are performed in the field of low- and medium-velocity impact. The chosen flat nose shape results in small penetrations on the top side and scabbing on the bottom side. The plate is scanned with an adapted planar tomographic examination after the impact, and the damage is analysed, afterwards. Cracks and spalling are made visible with a reconstruction. The numerical model validated on the tomographic results justifies the application for further predictions of the damage description. T2 - 25th International Conference on Structural Mechanics in Reactor Technology - SMIRT25 CY - Charlotte, NC, USA DA - 04.08.2019 KW - Impact KW - Damage characterization KW - Planar tomography KW - Numeric simulation KW - Reinforced concrete structure PY - 2019 SP - Paper Div 5 S8, 1 EP - 9 AN - OPUS4-49541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bhuyan, Md Delwar Hossain A1 - Gautier, G. A1 - Le Touz, N. A1 - Döhler, M. A1 - Hille, Falk A1 - Dumoulin, J. A1 - Mevel, L. T1 - Vibration‐based damage localization with load vectors under temperature changes N2 - Damage detection and localization in civil or mechanical structures is a subject of active development and research. A few vibration‐based methods have been developed so far, requiring, for example, modal parameter estimates in the reference and damaged states of the investigated structure, and for localization in addition a finite element model. For structures in operation, temperature has been shown to be a major nuisance to the efficiency of such methods because the modal parameters are varying not only with damage but also due to temperature variations. For detection, a few rejection approaches have been developed. Besides the increased complexity, environmental variation is hardly taken into account in localization approaches. In this paper, we propose a sensitivity‐based correction of the identified modal parameters in the damaged state with respect to the temperature field in the reference state, on the basis of a sensitivity analysis with respect to temperature dependent Parameters of the finite element model in the reference state. The approach is then applied to the stochastic dynamic damage locating vector method, where its improved performance under nonuniform temperature variations is shown in a numerical application on a beam. KW - Statistical evaluation KW - Damage localization KW - Load vector KW - Temperature effect rejection KW - Temperature modeling PY - 2019 U6 - https://doi.org/10.1002/stc.2439 SN - 1545-2255 SN - 1545-2263 SP - e2439, 1 EP - 16 PB - John Wiley & Sons, Ltd. AN - OPUS4-48843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thiele, Marc A1 - Hille, Falk A1 - Makris, Ruben ED - Helmerich, Rosemarie ED - Ilki, A. ED - Motavalli, M. T1 - Comparison of fatigue crack detection methods for high-cyclic loaded steel structures N2 - At present, to produce renewable energy offshore wind farms play an important role. The available space combined with the more valuable wind conditions make offshore locations very attractive for wind powered energy production. In Europe a significant number of offshore wind farms already exist, especially in the North and Baltic Sea. In future this trend will continue, and further offshore wind farms will be built. The majority of offshore wind turbines are mounted on steel foundation structures. Due to the high-cyclic loading by wind and waves fatigue stress plays a substantial role regarding structural safety. Besides the consideration of fatigue within the design process, to monitor existing steel structures for potential fatigue cracks during their life time is a major topic and a challenge. For the structures of the offshore wind turbines are large and partially under water effective reliable methods for the detection of fatigue cracks are required. This contribution presents investigations on different crack detection methods applied at high-cycle fatigue tests on small-scale welded steel samples as well as on large-scale welded steel components. The tests were conducted at the BAM laboratories. For crack detection mainly three different methods were used and compared. The first method regards to the measurement of strain by conventionally strain gauges. Secondly, the crack luminescence was used as a new and effective optical method for surface monitoring. And finally, crack detection by pressure differentials of the inner and outer section of tubular steel elements was investigated. A comparison study will emphasize the advantages and disadvantages of the different methods and show which of the described methods is potentially more suitable for an application on real offshore wind structures. T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures CY - Potsdam, Germany DA - 27.08.2019 KW - Fatigue KW - Steel structures KW - Crack detection PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-489433 SP - Th.2.A.1-1 EP - Th.2.A.1-8 AN - OPUS4-48943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -