7.2 Ingenieurbau
Filtern
Dokumenttyp
- Vortrag (161) (entfernen)
Referierte Publikation
- nein (161)
Schlagworte
- Structural Health Monitoring (16)
- Offshore wind energy (9)
- Fatigue (8)
- Ground vibration (8)
- Brücken (7)
- Offshore (7)
- Design methods (6)
- Physical phenomenology (6)
- Pile foundations (6)
- Structural health monitoring (6)
- Offshore wind turbines (5)
- SHM (5)
- Bahnerschütterungen (4)
- Building vibration (4)
- Deterioration (4)
- Foundations (4)
- Gründungsstrukturen (4)
- Model interpolation (4)
- Monitoring (4)
- Numerical modelling (4)
- Structural systems (4)
- Buckling (3)
- Damage characterization (3)
- Datenmanagement (3)
- Deep foundations (3)
- Erschütterungsminderung (3)
- Grout (3)
- Hammer impact (3)
- Impact (3)
- Inspection (3)
- Leichtbau (3)
- Maintenance (3)
- Monopiles (3)
- Offshore Windenergieanlagen (3)
- Offshore geomechanics (3)
- Physical testing (3)
- Planar tomography (3)
- Probabilistic (3)
- Shell Buckling (3)
- Slab track (3)
- Soil-structure interaction (3)
- Steel structures (3)
- Train passage (3)
- Vibration (3)
- Wind Energy (3)
- Windenergie (3)
- Zivile Sicherheit (3)
- AISTEC (2)
- Automatisierte schweißtechnische Fertigung (2)
- Bayesian updating (2)
- Belastungsversuch (2)
- Bridges (2)
- Compaction Grouting (2)
- Container loading (2)
- Crack detection (2)
- Damage detection (2)
- Design (2)
- Dispersionsmessung (2)
- Drop test (2)
- Elastische Elemente (2)
- Elastische Gleiselemente (2)
- Emission (2)
- Environmental effects (2)
- Erosion (2)
- Erschütterungen (2)
- Erschütterungsprognose (2)
- Fault detection (2)
- Foundation load (2)
- GPU parallel computation (2)
- Großer Fallturm Horstwalde (2)
- High-strength concrete (2)
- Inspection planning (2)
- Klimakammer (2)
- Layered soil (2)
- Micromechanical modelling (2)
- Modalanalyse (2)
- Numeric simulation (2)
- Offshore Pile Foundation (2)
- Offshore foundations (2)
- Offshore geotechnics (2)
- Offshore wind (2)
- Pile Tip Buckling (2)
- Railway (2)
- Railways (2)
- Reinforced concrete structure (2)
- Reliability (2)
- Repair (2)
- Risslumineszenz (2)
- Schwingungsdynamik (2)
- Statistical method (2)
- Subspace-based method (2)
- Temperature effects (2)
- Temperature rejection (2)
- Train-induced ground vibration (2)
- Tunnel (2)
- Ultrasonic testing (2)
- Vehicle-track-soil interaction (2)
- Vibration measurement (2)
- Vibration measurements (2)
- Wellengeschwindigkeit (2)
- Wind (2)
- Windenergy (2)
- 2-span bridge (1)
- Achsimpulse (1)
- Acoustic emission testing (1)
- Amplitude-charge weight laws (1)
- Amplitude-distance laws (1)
- Amplituden-Abstands-Gesetze (1)
- Analysis of variance (1)
- Ansys Autodyn (1)
- Apartment building (1)
- Artificial Intelligence (1)
- Artificial intelligence (1)
- Asphalt (1)
- Assessment (1)
- Attenuation (1)
- Automatisierte Fertigung (1)
- Automatisierte schweißtechniche Fertigung (1)
- Axial load bearing (1)
- Axle impulses (1)
- Axle pulses (1)
- Axle-sequence spectrum (1)
- BAM Windenergie Fügetechnik (1)
- Bahngleis (1)
- Ballast track (1)
- Base isolation (1)
- Baugrunddynamik (1)
- Bauwerk-Boden-Wechselwirkung (1)
- Bauwerksmonitoring (1)
- Bauwerksüberwachung (1)
- Bayes'sche Analyse (1)
- Bayesian System Identification (1)
- Bayesian methods (1)
- Bayesian system identification (1)
- Belastungsfahrt (1)
- Belastungszug (1)
- Beulen (1)
- Big Data (1)
- Bionik (1)
- Blast (1)
- Bodenschlitz (1)
- Bodenübertragungsfunktion (1)
- Boundary element method (1)
- Box-Behnken (1)
- Bridge (1)
- Brücke (1)
- Buckling piles circular shells (1)
- Building information modelling (1)
- CFD (1)
- Cars (1)
- Changing process noise (1)
- Chemisoprtion (1)
- Climate Chamber (1)
- Climate chamber (1)
- Compressive Cyclic loading (1)
- Compressive cyclic loading (1)
- Compressive strength (1)
- Computer Vision (1)
- Concrete (1)
- Crack Luminescence (1)
- Crack formation (1)
- Crack pattern (1)
- Crack repair (1)
- Cracks (1)
- Cyclic axial shearing (1)
- Cyclic degradation (1)
- Cyclic load (1)
- DEM (1)
- DEM-LBM simulation (1)
- DUCON® (1)
- Damage Detection (1)
- Damage identification (1)
- Deckeneigenfrequenzen (1)
- Deckenschwingungen (1)
- Design models (1)
- Design practice (1)
- Digital Image Correlation (1)
- Digital Twin (1)
- Digital twin (1)
- Digitalisierung (1)
- Displacements (1)
- Drone (1)
- Drop Test (1)
- Drucker-Prager (1)
- Ductility (1)
- Dynamic soil properties (1)
- Dynamische Bodenkennwerte (1)
- Dämpfung (1)
- E-modulus (1)
- EERA Joint Program (1)
- Earth masonry (1)
- Earthen hydraulic constructions (1)
- Earthen hydraulic infrastructures (1)
- Einflusslinie (1)
- Einflusslinien (1)
- Einfügungsdämmung (1)
- Elastische Gebäudelagerung (1)
- End-of-life decision making (1)
- Energy (1)
- Entscheidungsfindung (1)
- Environmental (1)
- Environmental Effects (1)
- Ermüdungsprüfung (1)
- Ermüdungsschäden (1)
- Erneuerbare Energien (1)
- Erosion of cohesive soils (1)
- Erschütterungen im Fernfeld (1)
- Erschütterungsausbreitung (1)
- Evaluation (1)
- Excitation forces (1)
- Explosion-induced ground vibrations (1)
- FEM (1)
- Fahrzeug-Fahrweg-Boden-Wechselwirkung (1)
- Faseroptik (1)
- Fatigue deterioration (1)
- Fiber optic sensing (1)
- Filter effects (1)
- Finite Elemente Simulation (1)
- Finite element models (1)
- Flexibility (1)
- Floors (1)
- Fluid-structure interaction (1)
- Fly ash (1)
- Footbridge (1)
- Force reconstruction (1)
- Freight train (1)
- Frequency response function (1)
- GMNIA (1)
- GNSS (1)
- GPU parallelisation (1)
- Gebäudelagerung (1)
- Gebäudemodelle (1)
- Gebäudeschwingungen (1)
- Geomechanics (1)
- Geomechanics of offshore foundations (1)
- Geometrie (1)
- Gleiströge (1)
- Granular Cohesive Materials, (1)
- Ground (1)
- Ground vibration measurements (1)
- Grout Injection (1)
- Grouted Connection (1)
- Grouted connection (1)
- Grouting (1)
- Halbraum (1)
- High-rise buildings (1)
- High-speed train (1)
- Immission (1)
- Impact damage of reinforced concrete (1)
- Impedanzmethode (1)
- Inertial interaction (1)
- Injection Sequence (1)
- Inspeciton (1)
- Interface (1)
- Interface model (1)
- Irregular ballast (1)
- Irregular soil (1)
- Irregularities (1)
- Jacket support structure (1)
- Jet erosion test (1)
- Kinematic interaction (1)
- Knudsen effect (1)
- Kraft auf den Boden (1)
- LBM-DEM (1)
- LBM-DEM coupling (1)
- Laboratory beam structure (1)
- Lateral load bearing (1)
- Layered soils (1)
- Leichtbauprinzipien (1)
- Linear parameter varying systems (1)
- Load Test (1)
- Load bearing behaviour (1)
- Long-term shrinkage (1)
- Macromechanical Sample Strength (1)
- Maintal Bridge Gemuenden (1)
- Maintalbrücke Gemünden (1)
- Marine geotechnics (1)
- Material Point Method (1)
- Material moisture (1)
- Material tests (1)
- Measurement (1)
- Measurements (1)
- Mechanical challenges (1)
- Messfahrt (1)
- Metakaolin (1)
- Micro silica (1)
- Micro-reinforcement (1)
- Microfine cement (1)
- Micromechanical LBM-DEM simulation (1)
- Micromechanical Tensile Failure (1)
- Micromechanical analysis (1)
- Micromechanical simulation (1)
- Mitigation (1)
- Mix design (1)
- Mobile elements (1)
- Modal Analysis (1)
- Modal load spectrum (1)
- Modal system identification (1)
- Model Update (1)
- Model updating (1)
- Modellierung (1)
- Modes and waves (1)
- Molecular diffusion (1)
- Monopile (1)
- Monopile Buckling (1)
- Movin load test (1)
- Non destructive testing (1)
- Non-Destructive Evaluation (1)
- Non-destructive testing (1)
- Normung (1)
- Numerical analysis (1)
- Numerical model (1)
- Numerical modeling (1)
- Numerical simulation of impact damage (1)
- Offhore (1)
- Office tower (1)
- Offshore Structures (1)
- Offshore Wind Energy (1)
- Offshore Wind Energy Converter (1)
- Offshore Windenergie (1)
- Offshore pile foundations (1)
- Offshore wind energy foundations (1)
- Offshore wind farm (1)
- Offshore wind farms (1)
- Offshore wind-turbine foundations (1)
- Offshore-Wind (1)
- Offshore-Windenergieanlagen (1)
- Operational modal analysis (1)
- Optimal Sensor Placement (1)
- Passenger train (1)
- Pfahlfußbeulen (1)
- Pfahlnachgiebigkeiten (1)
- Physisorption (1)
- Pile Buckling (1)
- Pile Capacity (1)
- Pile Foundation (1)
- Pile ageing (1)
- Pile groups (1)
- Pile retrofit system (1)
- Pile-Tip-Buckling (1)
- Point Cloud (1)
- Post-impact evaluation (1)
- Prediction (1)
- Prediction of explosion induced ground and building vibration (1)
- Predictive maintenance (1)
- Probabilitische Ingenieurmodelle (1)
- Probability of Detection (1)
- Prognose (1)
- Quasi-static and dynamic tests (1)
- Radar (1)
- Railbridge (1)
- Railway bridge (1)
- Railway tracks (1)
- Railway trafiic (1)
- Railway tunnel (1)
- Randelementmethode (1)
- Randomly heterogeneous soil (1)
- Rayleighwellendispersion (1)
- Rechenmodelle (1)
- Rechenverfahren (1)
- Rehabilitation (1)
- Reinforced concrete (1)
- Repowering (1)
- Research data management (1)
- Residual evaluation (1)
- Richtige Fahrzeugmasse (1)
- Risiko (1)
- Risikoanalyse (1)
- Risk (1)
- Risk-based maintenance planning (1)
- Rissprozes (1)
- Rissprozess (1)
- Road bridges (1)
- SHM Environmental (1)
- Safety (1)
- Scaling (1)
- Scattering (1)
- Schadensdetektion (1)
- Schadensüberwachung (1)
- Schienenfahrweg (1)
- Schienenfahrwege (1)
- Schwingungsbasierte Verfahren (1)
- Schwingungsmonitoring (1)
- Shrinkage (1)
- Simple and fast prediction (1)
- Simulation and experiment (1)
- Site-characterization (1)
- Size effect (1)
- Slenderness effect (1)
- Soil Struture Interaction (1)
- Soil erosion (1)
- Soil properties (1)
- Soil-Structure-Interaction (1)
- Soil-pile interaction (1)
- Soil-wall floor model (1)
- Soil-water-structure interaction (1)
- Spektralanalyse (1)
- Stability Buckling soil-structure-interaction piles offshore (1)
- Stabilität (1)
- Static load (1)
- Statistical correlations (1)
- Statistical tests (1)
- Statistische Korrelationen (1)
- Stereo photogrammetry (1)
- Stochastic Subspace Damage Detection (1)
- Structural Systems (1)
- Structural integrity (1)
- Structural integrity maintenance (1)
- Structural integrity management (1)
- Strukturmonitoring (1)
- Störgrößen (1)
- Subspace methods (1)
- Subspace-based residual (1)
- Substructures (1)
- Supplementary cementitious materials (1)
- Support structures (1)
- Surface line (1)
- Surface-tunnel reduction (1)
- System Identification (1)
- System identification (1)
- Systemidentifikation (1)
- TOP (1)
- Temperatureinflüsse (1)
- Tensile Capacity (1)
- Time-variant reliability (1)
- Tip Buckling (1)
- Tomographic damage evaluation (1)
- Track damage (1)
- Train configuration (1)
- Train excitation (1)
- Train passages (1)
- Train speed (1)
- Tran speed (1)
- Transfer fuction (1)
- Transmission (1)
- Tunnel line (1)
- Tunnelstrecke (1)
- UHPC (1)
- Umwelteinflüsse (1)
- Un- certainty (1)
- Uncertainty (1)
- Uncertainty in reference (1)
- Unterraummethoden (1)
- Value of Information (1)
- Varying soil stiffness (1)
- Varying track stiffness (1)
- Vibration monitoring (1)
- Vibrations (1)
- Vollraum (1)
- Water-structure interaction (1)
- Wave-Tower interaction (1)
- Wellenausbreitung (1)
- Wellenausbreitung in der Tiefe (1)
- Wellenfeldberechnung (1)
- Wind Energy Structures (1)
- Wind Turbines (1)
- Wind energy (1)
- Wind turbines (1)
- Wind-farm aerodynamics (1)
- Windfarm wake analysis (1)
- Zuggeschwindigkeit (1)
- elastische Gebäudelagerungen (1)
- risk, reliability, inspection planning, offshore wind turbines (1)
- zerstreute Achslastimpulse (1)
- Übertragungsmatrizen (1)
- Überwachung (1)
Organisationseinheit der BAM
- 7.2 Ingenieurbau (161) (entfernen)
Unterraumbasierte Detektion von Strukturschäden an Jacket-Gründungen von Offshore-Windenergieanlagen
(2018)
Die vorliegende Arbeit beschreibt die Adaption eines globalen, schwingungsbasierten Verfahrens zur frühzeitigen Erkennung von Strukturschäden an Gründungsstrukturen offshore installierter Windenergieanlagen (OWEA). Damit soll es, Betreibern von Offshore-Windparks ermöglicht werden, im Rahmen periodisch durchgeführter messtechnischer Überwachungsmaßnahmen mit einem gegenüber wiederkehrender Inspektionen wesentlich geringen Aufwand auftretende Schäden an der Struktur zuverlässig zu delektieren.
Das untersuchte und implementierte Verfahren basiert auf der Methode der stochastischen unterraumbasierten Schadensdetektion. Dabei erfolgt eine statistische Analyse des wiederkehrend messtechnisch aufgenommenen dynamischen Antwortverhaltens des mechanischen Systems. Mittels statistischem Test werden signifikante Änderungen in dessen Eigenstruktur und damit Schäden delektiert.
Im Rahmen der vorliegenden Arbeit wurden umfangreiche experimentelle als auch numerische Untersuchungen zur Sensitivität und Robustheit des beschriebenen Schadensindikators durchgeführt. Dazu sind zunächst an einem Labormodell mittels künstlich und reversibel eingebrachter Schäden grundlegende Analysen zu den Einflüssen signal- und verfahrensinhärenter Kenngrößen durchgeführt worden. Auf der Basis dieser Ergebnisse wurde im Anschluss mittels numerischer Analysen das Antwortverhalten von OWEA simuliert und der entwickelte Algorithmus zur Schadensdetektion an den so realisierten Datensätzen angewendet.
Anhand der Ergebnisse der Arbeit wird aufgezeigt, dass, vorausgesetzt die Windenergieanlage befindet sich in Parkposition, eine Detektion von schon geringen Schäden an Gründungs-strukturen mit dem beschriebenen Verfahren, auch unter Einsatz weniger Messaufnehmer, zuverlässig möglich ist.
Risslumineszenz
(2018)
Mit der Errichtung und der Inbetriebnahme des Windpark alpha ventus wurden umfangreiche Messungen an den Tragstrukturen und den Umgebungsparametern durchgeführt. Im Projekt Gigawind life wurde im TP1 ein Datenmanagementsystem zur kontinuierlichen und periodisch fortgeführten Datenauswertung für große Datenbestände (Big Data) entworfen und realisiert. Anhand von Performanceuntersuchungen konnte eine Verkürzung der Rechenzeit um den Faktor 10 in einem Rechencluster erreicht werden. Unter Anwendung einer Datenpipeline nach dem Publish/Subscribe Prinzip wird eine skalierbare Datenschnittstelle für Monitoringdaten vorgeschlagen.
Superplasticizer and shrinkage reducing admixture dosages for microfine cement in grout systems
(2018)
Grouts have numerous applications including crack repair as maintenance in construction industries. Microfine cements are intensively used for high strength mortar and grout products. They are ideal for injection grouting in structural repair. Such grouts should have suitable rheological properties to be injectable, especially those used in repair and rehabilitation. The use of superplasticizers (SP) in these products is thus becoming increasingly crucial to achieve favorable workability and viscosity properties. A difficulty in such grouts is the plastic shrinkage due to finer particles used. It is thus necessary to determine optimum SP and shrinkage reducing admixture (SRA) dosages for a microfine cement based grout. In this study, a saturation dosage was decided from two Polycarboxylate ether (PCE) based SPs in relation to neat cement using slump flow and rheological parameters. A range of grout mixtures was formulated containing micro silica (MS) and fly ash (FA), and tested for suitable rheological and mechanical parameters. Based on the results, a grout mixture with MS and FA was selected to determine optimum SRA content. According to the results, a SP dosage of 3% by weight of neat cement is sufficient to achieve saturation. The grout material including MS and FA can produce comparable properties to neat cement grout. MS is found to improve compressive strength within the range considered, whereas a higher FA content provides favourable rheological properties. Finally, a SRA dosage of 4%, which could reduce the shrinkage by about 43% after 28d days, is determined for the grout system.
This presentation deals with the phenomenology and design of pile foundations for offshore wind turbines, and is divided in two lectures.
The first lecture presents a brief introduction to the context and peculiarities of such foundations, and then focuses on the particular case of axially loaded piles. This part is most relevant for the relatively slender piles of the multi-pile substructures (i.e. jackets and tripods). A clear distinction between physical phenomenology and practical design is drawn here.
The second lecture continues with the case of lateraly loaded offshore piles, which bears most relevance for the case of the monopile foundations. Here again, a clear separation between physical reality and design methods is intended.
Finally, the last part of the second lecture introduces several advanced topics which lie outside the classical design approaches, namely the cyclic pile fatigue and the so-called pile setup (i.e. the time effects on the axial pile capacity). The relevance of these two topics is illustrated with experimental results from a field testing campaign on real large-scale piles.
This talk provides a brief introduction on general engineering aspects of offshore wind energy production. Some geomechanical issues for the foundation of OWTs into the seabed are introduced, while the results from experimental investigations and coupled computational analysis are discussed.
In the second part of the seminar, the hydromechanical Wave–Tower interaction is firstly discussed. Then, some general aspects of the windfarm aerodynamics are introduced. On the one hand, some modelling possibilities for the wake analysis of single turbines and turbine groups are discussed. And on the other hand the relevance of such analyses for a proper windfarm layout optimization is pointed out.
Concerning the geomechanical issues the talk shows that: i) The pile’s bearing capacity can degrade under cyclic loading (waves, wind, …). ii) The time effects can be relevant: Capacity improvement can be substantial, but also fragile. iii) There are cyclic PWP effects: Cyclic interaction with pore water may lead to soil softening and an uncoupled analysis (current design practice) is potentially unsafe.
And concerning the hydromechanical and aerodynamical design considerations, this seminar shows that: i) Numerical analysis of turbine’s interaction with wind/waves is useful and affordable. ii) Simplified models can provide insight into windfarm aerodynamics. iii) Turbulent wake analysis is very relevant for the windfarm layout.
Use of DEM-LBM modeling to prove the relevance of free jet model for soil erosion by impinging jet
(2018)
The aim of this study is to provide a micromechanical insight into the mechanisms taking place during the erosion of a cohesive granular material driven by a fluid flow, the objectives are summarized as follows:
Perform numerical erosion tests.
Parallelization of the code (Gpu).
Extensive parametric analysis => rely micro parameters (eg. Cohesion) to macro parameters (eg. Soil erodibility, mechanical strengths).
Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced.
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.
Subspace-based damage detection handling temperature effects and uncertainty in the reference
(2019)
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.
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.
This presentation provides an overview on general issues related to erosive failures in civil constructions like hydraulic infrastructures and offshore foundations. A brief introduction to the related research activities of BAM in the field of offshore wind energy is first provided, and the general possibilities for micromechanical modelling approaches are outlined. Finally, the ongoing DFG-ANR research project COMET is introduced.
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.
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.
This talk provides a brief introduction on general engineering challenges for the offshore (marine) wind energy production, focusing on material, structural and hydromechanical aspects.
The talk begins with a broad overview on general trends for offshore wind-farms, with insights on some characteristic structural features and their associated loads. Then, some particular open issues for the foundation of the offshore wind turbines into the seabed are introduced. Here, different research approaches are discussed, from experimental investigations to coupled computational analysis at micro- and macroscopic scales.
In the second part of the seminar, both the hydromechanical Wave–Tower interaction and some general aspects of the windfarm aerodynamics (wake analysis) are discussed. Some modelling possibilities in the frame of CFD (computational fluid dynamics) are introduced and the relevance of such analyses for a proper windfarm layout optimization is pointed out.
Summing up, this seminar aims to show that: i) Numerical analysis of the turbine’s interaction with wind/waves and with the seabed is both useful and affordable. ii) Simplified models can provide an insight into windfarm aerodynamics. iii) Turbulent wake analysis is very relevant for the windfarm layout.