Proceedings of the Belgian-Dutch IABSE Young Engineers Colloquium 2019:YEC2019

The proceedings contain 35 papers. The topics discussed include: fatigue monitoring of railway bridges by means of virtual sensing; steel-supported glazed atrium roof between two adjacent existing buildings; the Boekelose bridge: an innovative structure; case study of rail-bridge interaction of a large span railway viaduct in riga; probabilistic approach to evaluate fatigue safety status in steel railway bridges; buckling design approach for unstiffened curved plates in uniform shear; finite element modeling of residual welding stresses in an orthotropic steel bridge component; uniformly loaded tensegrity bridge design via morphological indicators method; tensile and shear resistance of bolted connectors in steel-FRP hybrid beams; and parametric analysis of rib distortion induced stress concentration at rib-to-crossbeam joint.</p

The mechanics of composite corrugated structures: A review with applications in morphing aircraft

Corrugation has long been seen as a simple and effective means of forming lightweight structures with high anisotropic behaviour, stability under buckling load and energy absorption capability. This has been exploited in diverse industrial applications and academic research. In recent years, there have been numerous innovative developments to corrugated structures, involving more elaborate and ingenious corrugation geometries and combination of corrugations with advanced materials. This development has been largely led by the research interest in morphing structures, which seek to exploit the extreme anisotropy of a corrugated panel, using the flexible degrees of freedom to allow a structure’s shape to change, whilst bearing load in other degrees of freedom. This paper presents a comprehensive review of the literature on corrugated structures, with applications ranging from traditional engineering structures such as corrugated steel beams through to morphing aircraft wing structures. As such it provides an important reference for researchers to have a broad but succinct perception of the mechanical behaviour of these structures. Such a perception is highly required in the multidisciplinary design of corrugated structures for the application in morphing aircraft

Textile hybrid kinetic adaptive structures: a case study

Dissertação de mestrado integrado em Engenharia CivilThis thesis has the main objective to study three distinct typologies of structures. These structures are, form-active structures, in particular membrane structures, bending-active structures and the integration of both concepts with a kinetic principle, therefore adaptive hybrid structures. Both membrane and bending-active are structures that require form finding, since the form of these structures is dependent on the loading and boundary conditions, thus only known a posteriori. These structures are subject to large deformations and thus, geometric nonlinearities must be considered during the calculation. Additionally, the flexibility of membrane structures conjugated with the elastic behaviour of bending-active structures creates the perfect conditions for the development of hybrid kinetic structures that adapt according to the external loading conditions present. This study intends to elaborate an exploratory approach on these concepts, thus bringing forward the main problems that originate when analysing a structure of this type. Therefore, firstly a study on membrane, bending-active, hybrid and kinetic structures is presented, containing the most relevant knowledge that currently exists regarding these topics. Then, the structural aspects that are inherent to these structures are exposed. Three routines are developed in Sofistik® in order form find and calculate the above-mentioned structures. Validations are made on these routines and software analysis. The structural feasibility of an architectural concept proposed by Costa (2017) of a hybrid adaptive concept is studied by applying these routines, and the kinetic hybrid concept is simulated in Sofistik®. The adaptive principle is also extended to function structurally, by taking advantage of the bending prestress implied by the bending-active elements. Finally, external wind loads are applied to this structure, in order to test the effectiveness of the structural adaptive concept. It was concluded that there is significant importance of the bending adaptive movement in the loadbearing capacity of the overall system. Additionally, the choice of the initial shape of the structure defines a crucial step on the definition of the structure, since it affects the process of form finding, that latter affects the structural performance.A presente dissertação tem como objetivo principal estudar três tipologias distintas de estruturas. Estas estruturas são as estruturas de forma ativa, particularmente as estruturas em membrana, as estruturas de flexão ativa e a integração de ambos os conceitos com um princípio cinético, ou seja, estruturas hibridas adaptativas. Tanto as estruturas de membranas como as estruturas de flexão ativa são estruturas que requerem determinação da forma pois, como a forma destas estruturas é dependente das condições de tensão e de fronteira, apenas é conhecida a posteriori. Estas estruturas estão sujeitas a grandes deformações e, portanto, as não linearidades geométricas devem ser consideradas durante o cálculo. Para além disto, a flexibilidade das estruturas de membrana conjugada com o comportamento elástico das estruturas de flexão ativa geram condições perfeitas para o desenvolvimento de estruturas cinéticas hibridas que se adaptam de acordo com as condições de carregamento presentes. Este estudo pretende elaborar uma aproximação exploratória a estes conceitos, trazendo para primeiro plano os principais problemas originários da análise deste tipo de estruturas. Desta forma, primeiramente é apresentado um estudo sobre estruturas de membrana, flexão ativa, hibridas e cinéticas, contendo a informação mais relevante que existe atualmente sobre estes assuntos. De seguida, os aspetos estruturais inerentes a estas estruturas são expostos. Três rotinas são desenvolvidas no Sofistik® de forma a determinar a forma e calcular as estruturas anteriormente mencionadas. São realizadas validações destas rotinas e da análise preconizada pelo software. A viabilidade estrutural de um conceito de arquitetura proposto por Costa (2017) sobre uma estrutura hibrida adaptativa é estudada através da aplicação destas rotinas, e o princípio cinético hibrido é simulado através do Sofistik®. O princípio adaptativo é alargado de modo a funcionar estruturalmente, tirando partido da pretensão implícita pelos elementos de flexão ativa. Finalmente, são aplicadas cargas externas de vento à estrutura, de forma a testar a eficácia do principio adaptativo estrutural. Foi concluído que o movimento adaptativo de flexão tem uma importante significância ao nível da carga admissível na estrutura. Adicionalmente, a escolha da geometria inicial da estrutura define uma etapa fundamental na definição da estrutura, pois afeta o processo de form finding, que mais tarde afeta o desempenho estrutural

Mitigation of urban storm water runoff through application of computational fluid dynamics

This thesis covers computational methods for improving the ability of green roofs to mitigate storm water runoff in urban environments. Roofs with living vegetation, known as green roofs, have been used for this purpose however quantification of their ability to slow and stop rainfall runoff has not been undertaken to a large degree. In this work two different approaches are taken: i) to improve green roof performance by optimizing their location on a building facade; and ii) to optimize the design of the growth substrate by examining the impact of the porous microstructure on infiltrating flow. The approach for optimization by placement makes use of traditional computational fluid dynamics and applies a full turbulence model to an Eulerian multiphase system consisting of a steady-state wind phase and a set of transient rainfall phases. The rainfall phases are determined by droplet size and the quantity incident upon the building facade is calculated and compared to experimental results. The analysis shows that the accuracy varies widely dependent upon location upon the structure and several sources of error are discussed. The second approach makes use of the lattice Boltzmann technique to aid in the deisgn of the growth substrate. Several representative porous media are generated using monodisperse randomly packed particles and gravity-driven infiltration is tracked from an initialized standing water height above the porous subdomain. Many aspects of the flow and properties of the microstructure are analyzed and conclusions are drawn based upon such factors as interfacial area, saturation rate, capillary pressure, and pore size distribution. Guidelines are drawn to aid in the design of thin homogeneous growth substrates based upon the findings. These ideal cases are compared to simulations performed on XMT scans of real growth substrate material and some conclusions are drawn on the observed differences

Traditional and Innovative Approaches in Seismic Design

This special issue collects selected papers about a wide range of innovative applications in earthquake engineering. These studies were presented during the 2nd Edition of the International Workshop “Traditional and Innovative Approaches in Seismic Engineering”, held in Pisa in March 2017. The topics refer to the investigation of traditional and innovative materials for earthquake engineering applications: masonry, reinforced concrete, steel, structural glass and timber. In particular, advanced analytical and numerical analyses are described for considering effects of strength and material irregularities and rocking behavior under seismic excitations on historic buildings and industrial facilities. Experimental tests are also illustrated with the purpose of investigating the strengthening on masonry arches due to lime-based mortar composites and of obtaining reliable values of stiffness for moment resisting steel-timber connections. Among the innovative approaches, studies on original pavilions made of long-spanned TVT-portals braced with hybrid glass-steel panels are illustrate

Numerical Simulation of Selected Two-Dimensional and Three-Dimensional Fluid-Structure Interaction Problems Using OpenFOAM Technology

Fluid-structure interaction (FSI) problems are increasing in various engineering fields. In this thesis, different cases of FSI in two- and three-dimensions (2D and 3D) are simulated using OpenFOAM and foam-extend. These packages have been used to create a coupling between fluid and solid. The vortex-induced vibration (VIV) phenomenon of flow past a circular cylinder is studied using PIMPLE algorithm for pressure-velocity coupling. This VIV study is restricted to incompressible flow simulation at a Reynolds number (Re) of 100. The changes of drag and lift coefficient values depend on the study case and the spring-mass-damper system for the flow past a free oscillatory cylinder. The free vibrating cylinder examined in one-degree-of-freedom (1DOF) and two-degrees-of-freedom (2DOF) systems with linear damping and spring properties. Both will affect the behaviour of the cylinder within the flow with some noticeable differences. The response time of the cylinder and the drag coefficient are the most affected by the spring and damper. Besides the vortex-induced vibration test cases, the two-dimensional and three-dimensional fluid-structure interaction benchmarking is also studied. A partitioned solution method for strongly coupled solver with independent fluid and solid meshes for transient simulation has been applied. The fluid domain dynamics is governed by the incompressible Navier-Stokes equations; however, the structural field is described by the nonlinear elastodynamic equations. Fluid and solid domains are discretised by finite volume method (FVM) in space and time. A strong coupling scheme for partitioned analysis of the thin-walled shell structure exposed to wind-induced vibration (WIV) is presented. The achievement of the 3D membrane roof coupling scheme is studied by applying the 2D model. Additionally, numerical models for the slender shell structures coupling and the 3D flows indicate possible applications of the presented work. The computational fluid dynamics (CFD) simulation results revealed that even the flow is considered as a laminar, turbulence modelling or more refined meshes should be used to capture the generation and release of vortices. A partitioned solution procedure for FSI problems in the building aeroelasticity area is also studied. An illustrative real-world model on the coupled behaviour of membrane structure under wind flow influence is given. A four-point tent subjected to wind motion is a typical application of this work applying with various physical factors that are a necessity for the thin membrane structure. The fluid domain is described by the incompressible Navier-Stokes equations at a Reynolds number of Re = 3,750. However, the motion of the solid field is modeled by total Lagrangian strategy for nonlinear elastic deformation. The FSI simulation, particularly 3D problems require in very long calculation time. Some limitations of the FSI solver in foam-extend package called fsiFoam is discussed. All solvers that used in this thesis are considered to be applied to a wide use of the implementation of FSI models, despite some problems in parallelisation, particularly in the latest FSI solver version. The analysis results are presented to demonstrate accuracy, convergence, and stability