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 - Herrmann, Ralf A1 - Moortgat-Pick, A. A1 - Marx, S. ED - Helmerich, Rosemarie ED - Ilki, A. ED - Motavalli, M. T1 - Vibration Analysis of Structures using a Drone (UAV) based Mobile Sensing Platform N2 - The identification of the dynamic behavior of structures, like bridges and towers, is relevant to address multiple issues. In many cases the dynamic parameters should be acquired only once or at a frequency that doesn’t justify the installation of distinct vibration sensors for a long-term monitoring. To identify modal frequencies of a structure, a drone based mobile sensing platform has been implemented. This sensing platform measures the relative displacement be-tween the structure and the drone, which also shows a strong dynamic behavior under wind tur-bulences. By regarding the dynamic model of the drone and additional measurements at the dis-tance sensor the absolute movement of the structure can be estimated based on the measured relative distance. This time domain data is a suitable input for various operational modal analysis algorithms. The system has been used to identify the dynamic properties of test and real structure, like a 1.5 MW wind turbine tower. T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019) CY - Potsdam, Germany DA - 27.08.2019 KW - Modal Analysis KW - Drone KW - Vibration KW - Wind Turbines KW - Bridges PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-492045 UR - http://data.smar-conferences.org/downloads/SMAR_2019_Proceedings.zip SN - 978-3-947971-07-7 SP - We.4.C.3 EP - 8 PB - German Society for Non-Destructive Testing (DGZfP e.V.) AN - OPUS4-49204 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 - CONF A1 - Hüsken, Götz A1 - Shamsuddoha, Md A1 - Thiele, Marc A1 - Baeßler, Matthias A1 - Kühne, Hans-Carsten T1 - Comparison of cracks formed in scaled grouted connection of offshore energy structures under static and cyclic loads N2 - Global energy consumption will increase in the future necessitating both fossil fuels and renewable energy choices - especially wind energy. Such high energy demand requires installation of offshore energy structures, rigs, platforms and towers, which are susceptible to adverse environmental conditions along with maintenances. Due to their large size and remote locations, cylindrical grouted joints are often adopted between substructure and foundation in these offshore platforms and wind structures such as monopiles. However, these connections are composite structures with exterior sleeve, interior pile and infill mortar. Degradation and settlements were reported inside similar connections, which were installed in last three decades. Besides, grouting in the offshore sites were proven difficult to obtain ideal load bearing capacity. In-situ loading conditions were also found to be affecting the failure mechanism inside such connections. This study aims at characterizing the nature of cracks generated in these grouted connections under both static and cyclic loading. Scaled grouted joints were manufactured using a novel reusable mold, and connections were loaded to failure to visualize the main failure patterns. An assessment between failure under these two types of load is drawn along with comparison to previously available literature. T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures CY - Potsdam, Germany DA - 27.08.2019 KW - Grouted connection KW - Crack formation KW - Crack pattern KW - Static load KW - Cyclic load PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-487961 SP - Th.2.A.1-1 EP - Th.2.A.1-9 AN - OPUS4-48796 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kullolli, Borana A1 - Cuéllar, Pablo A1 - Baeßler, Matthias A1 - Stutz, H. H. T1 - Modelling and calibration for cyclic soil-structure interface behaviour N2 - The structural performance of many geotechnical systems (e.g. axially-loaded pile foundations), depends on the shearing resistance at the soil interface, which may govern the load bearing capacity of the foundation. Experimental investigations have shown that this interaction is mainly localised within a narrow shear band next to the structure. Under cyclic loading, a contraction of the soil at the interface may arise (net volume loss), possibly leading to a stress relaxation and thus to a reduction of the load bearing capacity (the so-called friction fatigue). Based on the constitutive similarities between soil continua and interfaces, we propose here the adaption of a Generalized Plasticity model for sandy soils for the numerical analysis of interface problems. In this contribution, the results of an experimental campaign for the parameter calibration of the constitutive model are presented. The tests have been conducted with a ring shear device involving different normal stresses, roughness of the steel plates as well as cyclic loading. The new modelling approach shows promising results and has the additional practical advantage that the interface zone and the soil continuum can both be described with the same constitutive model in general boundary value problems. T2 - Konferenz 7th International Symposium on Deformation Characteristics of Geomaterials CY - Glasgow, Scotland DA - 26.06.2019 KW - Soil-structure interaction KW - Offshore foundations PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-489096 VL - 92 SP - 13007 EP - 13013 PB - EDP Sciences CY - Glasgow, Scotland AN - OPUS4-48909 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -