Types Of Substructures Research Articles

Dynamical Consequence of Shadows Cast to the Outer Protoplanetary Disks. I. Two-dimensional Simulations

There has been increasing evidence of shadows from scattered light observations of outer protoplanetary disks (PPDs) cast from the (unresolved) disk inner region, while in the meantime these disks present substructures of various kinds in the submillimeter. As stellar irradiation is the primary heating source for the outer PPDs, the presence of such shadows thus suggests inhomogeneous heating of the outer disk in azimuth, leading to a “thermal forcing” with dynamical consequences. We conduct a suite of idealized two-dimensional disk simulations of the outer disk with azimuthally varying cooling prescription to mimic the effect of shadows, generally assuming the shadow is static or slowly rotating. The linear response to such shadows is two-armed spirals with the same pattern speed as the shadow. Toward the nonlinear regime, we find that shadows can potentially lead to the formation of a variety of types of substructures including rings, spirals, and crescents, depending on viscosity, cooling time, etc. We have conducted systematic and statistical characterization of the simulation suite, and as thermal forcing from the shadow strengthens, the dominant form of shadow-induced disk substructures change from spirals to rings, and eventually to crescents/vortices. Our results highlight the importance of properly modeling the dynamical impact of inhomogeneous stellar irradiation, while calling for more detailed modeling incorporating more realistic disk physics.

A Wave Drift Force Model for Semi-Submersible Types of Floating Wind Turbines in Large Waves and Current

The correct prediction of slowly varying wave drift loads is important for the mooring analysis of floating wind turbines (FWTs). However, present design analysis tools fail to correctly predict these loads in conditions with current and moderate and large waves. This paper presents a semi-empirical method to correct zero-current potential-flow quadratic transfer functions (QTFs) of horizontal wave drift loads in conditions with current and moderate and large waves. The method is applicable to column-stabilized types of substructures or semi-submersibles. In the first step, the potential-flow QTF is corrected for potential-flow wave–current effects by applying a heuristic method. Second, the generalized Exwave formula corrects for viscous drift effects. Viscous drift effects become important for moderate and large waves. Conditions with current in the same direction as the waves increase the viscous drift contribution further. The method is validated by comparing QTF predictions with empirical QTFs identified from model test data for the INO Windmoor semi. While potential-flow QTFs agree well with the empirical data for small seastates without current, they underestimate the wave drift loads for moderate and large seastates. Conditions with current increase the underestimation. The semi-empirical correction method significantly improves predictions.

Topological Characterization for Triangular, RegularTriangular Oxides and Silicates Networks

Chemical graph theory can be studied with the aid of mathematical tools called m-polynomials. M-Polynomials offer a potent tool for computing different topological indices associated with vertex degrees and analyzing degree-based structural information in graphs. By counting specific substructure types within them, they are able to encode information about the structure of molecules or networks. In this article, we have developed M-Polynomials with the help of different topological invariants such as first Zagreb (M1(β)), second Zagreb (M2(β)), second modified Zagreb (Mm2(β)), inverse sum (I(β)), harmonic index (H(β)) and Randic index (Rα0(β)) for the molecular structures of Triangular oxide TOX(r), Regular triangular oxide RTOX(r), Triangularsilicate TSL(r) & Regular triangular silicate RTSL(r) networks to introduce new closed formulas to get better understanding the applications of M-Polynomials and topological indices in mathematical chemistry especially in the field of QSAR and QSPR study with the help of some software like MATLAB. We have also discussed the graphical behaviors of the above-mentioned structures.

Influence of wind-wave characteristics on floating wind turbine loads: A sensitivity analysis across different floating concepts

Floating offshore wind turbines experience different operating conditions, such as wind and wave inflow characteristics. Accurate prediction of the loads acting on the floating wind system is essential for the system design and optimisation. However, there are a lot of uncertainties with the modelling input variables for time domain simulation tools such as OpenFAST to represent various hydro-aerodynamic and structural properties. The primary objective of this work is to identify the critical input parameters for different damage-equivalent load outputs for two substructure types: OC3 Hywind Spar and OC4 DeepCwind semisubmersible. The same rotor-nacelle assembly and tower (the NREL 5MW reference turbine) are used in both case studies. A sensitivity analysis based on the damage equivalent loads of six output quantities was conducted with 8 or 10 input parameters (depending on the floater). The dependent parameters were conditionally parameterised based on the independent inputs, such as wind speed and wind-wave misalignment.The outcomes of this work show that the floater type affects the sensitivity levels of wave characteristics and hydrodynamic drag coefficients with no significant influence on the turbulence intensity, as expected. Further, the drag coefficient for spar-buoy configuration significantly influences mooring line tension compared to the semisubmersible because of their drag-dominant slender structure. The current velocity is the most dominating parameter for the mooring loads, irrespective of the floater type. While wave characteristics also influenced some turbine loads, it was almost independent of the floater type. Furthermore, the choice of the hydrodynamic model does not affect the sensitivity level rankings. A convergence study on the number of starting points was conducted to ensure a global sensitivity approach. As seen in this study, the results are floating platform-specific. This study provides valuable insight into design-driving input parameters, characterising substructure-specific wind-wave influence.

METHOD OF CREATING A MINIMAL SPANNING TREE ON AN ARBITRARY SUBSET OF VERTICES OF A WEIGHTED UNDIRECTED GRAPH

Context. The relevance of the article is determined by the need for further development of models for optimal restoration of the connectivity of network objects that have undergone fragmentation due to emergency situations of various origins. The method proposed in this article solves the problematic situation of minimizing the amount of restoration work (total financial costs) when promptly restoring the connectivity of a selected subset of elements of a network object after its fragmentation.
 The purpose of the study is to develop a method for creating a minimal spanning tree on an arbitrary subset of vertices of a weighted undirected graph to minimize the amount of restoration work and/or total financial costs when promptly restoring the connectivity of elements that have a higher level of importance in the structure of a fragmented network object.
 Method. The developed method is based on the idea of searching for local minima in the structure of a model undirected graph using graph vertices that are not included in the list of base vertices to be united by a minimal spanning tree. When searching for local minima, the concept of an equilateral triangle and a radial structure in such a triangle is used. In this case, there are four types of substructures that provide local minima: first, those with one common base vertex; second, those with two common base vertices; third, those with three common base vertices; fourth, those without common base vertices, located in different parts of the model graph. Those vertices that are not included in the list of basic ones, but through which local minima are ensured, are added to the basic ones. Other vertices (non-basic) along with their incident edges are removed from the structure of the model graph. Then, using one of the well-known methods of forming spanning trees, a minimal spanning tree is formed on the structure obtained in this way, which combines the set of base vertices.
 Results. 1) A method for creating a minimal spanning tree on an arbitrary subset of vertices of a weighted undirected graph has been developed. 2) A set of criteria for determining local minima in the structure of the model graph is proposed. 3) The method has been verified on test problems.
 Conclusions. The theoretical studies and several experiments confirm the efficiency of the developed method. The solutions developed using the developed method are accurate, which makes it possible to recommend it for practical use in determining strategies for restoring the connectivity of fragmented network objects.

Union Subgraph Neural Networks

Graph Neural Networks (GNNs) are widely used for graph representation learning in many application domains. The expressiveness of vanilla GNNs is upper-bounded by 1-dimensional Weisfeiler-Leman (1-WL) test as they operate on rooted subtrees through iterative message passing. In this paper, we empower GNNs by injecting neighbor-connectivity information extracted from a new type of substructure. We first investigate different kinds of connectivities existing in a local neighborhood and identify a substructure called union subgraph, which is able to capture the complete picture of the 1-hop neighborhood of an edge. We then design a shortest-path-based substructure descriptor that possesses three nice properties and can effectively encode the high-order connectivities in union subgraphs. By infusing the encoded neighbor connectivities, we propose a novel model, namely Union Subgraph Neural Network (UnionSNN), which is proven to be strictly more powerful than 1-WL in distinguishing non-isomorphic graphs. Additionally, the local encoding from union subgraphs can also be injected into arbitrary message-passing neural networks (MPNNs) and Transformer-based models as a plugin. Extensive experiments on 18 benchmarks of both graph-level and node-level tasks demonstrate that UnionSNN outperforms state-of-the-art baseline models, with competitive computational efficiency. The injection of our local encoding to existing models is able to boost the performance by up to 11.09%. Our code is available at https://github.com/AngusMonroe/UnionSNN.

FLOATING OFFSHORE TURBINES - INSTALLATION METHODS

Floating offshore wind turbines are a possible source of large scale electricity. Fabrication and offshore installation design of these large floating structures is required to provide confidence to developers and insurers that they are constructed in a safe and cost effective manner. The design methods developed in this paper cover the substructure types such as Spars, semi submersibles, barges and TLPs. The engineering of mooring types includes catenary, taut and tension, plus turret mooring.This paper details the preparation of engineering requirements for installation vessels and large onshore cranes used for the shipyard construction of substructures for floating wind. Each installation phase, for a floating offshore wind turbine, raises issues regarding existing construction methods and the need to develop revised installation works.The engineering processes include mooring installation and connection. In addition consideration of load-out analysis, ocean transportation analysis including sea-fastening, intact stability and tow motion response. Installation analysis is required for lifting, up-ending, afloat construction, and cable lay methods.Floating offshore wind turbines are offering a new approach to using marine resources and this paper will provide information on how naval engineering can be used to promote this development.

Penetration Behavior of Jack-up Leg with Spudcan for Offshore Wind Turbine to Multi-layered Soils Using Centrifuge Tests

This study examined the jack-up spudcan penetration for a new type of offshore wind substructure newly proposed using the jack-up concept to reduce construction costs. The jack-up spudcan for offshore wind turbines should be designed to penetrate a stable soil layer capable of supporting operational loads. This study evaluated multi-layered soil conditions using centrifuge tests: loose sand over clay and loose sand–clay–dense sand. The penetration resistance profiles of spudcan recorded at the centrifuge tests were compared with the ISO and InSafeJIP methods. In the tests, a spudcan punch-through effect slightly emerged under the sand-over-clay condition, and a spudcan squeezing effect occurred in the clay-over-sand layer. On the other hand, these two effects were not critically predicted using the ISO method, and the InSafeJIP result predicted only punch-through failure. Nevertheless, ISO and InSafeJIP methods were well-matched under the conditions of the clay layer beneath the sand and the penetration resistance profiles at the clay layer of centrifuge tests. Therefore, the ISO and InSafeJIP methods well predict the punch-through effect at the clay layer but have limitations for penetration resistance predictions at shallow depths and strong stratum soil below a weak layer.

INFORMATION MODELING OF CONCRETE: CURRENT STATUS AND DEVELOPMENT PROSPECT S

The publication relates to the problems of digitalization of building materials science. The relevance of developing a digital model of concrete for solving optimization problems of design and synthesis of its structure, clarifying methods for calculating building structures, and improving the technology of their production is shown. The evolution of information modeling of concrete is analyzed in the context of the stages of development of system-building materials science and technology.
 A review of the main modern methods of computer modeling of concrete structure in domestic and foreign scientific research is provided. It is noted that these methods do not take into account the complexity of the structure of concrete. In the article, concrete is presented as a conglomerate composite with a hierarchically organized structure with dimensions from 10-10 to 10-1 m. It has a minimum of 5-6 scale levels and three types of substructure design. Substructures differ in their scale, genesis and mechanics of manifestation of properties. The first type of substructure is characteristic of the macro-, meso- and micro-scale levels. It is accepted in the form of a two-component “construction” of a spatially continuous matrix and discrete inclusions deterministically and stochastically distributed in it. The second type refers to the submicro-, ultra-micro- and nanoscale levels. It is believed to be in the form of a “microscale spatial structure” of new formations of a cementing substance from consolidated individual crystalline differences. The third type corresponds to the atomic-molecular structure of new formations of the cementing substance.
 The characteristics of each type of substructure are given according to: the scale of the components; features of formation; mechanics of properties manifestation; design criteria; means of synthesis. An assumption is made about the specificity of modeling each of the three types of concrete substructures and their integration into a single digital model. The task is to develop an information platform for such a model. The platform should include: a theoretical knowledge base; empirical data base; database of analytical, numerical and statistical models; algorithms for designing and synthesizing structures; optimization criteria and boundary conditions; terms of reference for computer modeling of concrete.

EMsFEM based concurrent topology optimization method for hierarchical structure with multiple substructures

An efficient concurrent topology optimization method based on the Extended Multiscale Finite Element Method (EMsFEM) is proposed to design the hierarchical structure with multiple substructures in this paper. Firstly, the mathematical description model for the topology of hierarchical structures and the interpolation model for material are established at both the macro and substructural levels. Then the concurrent topology optimization formulation for hierarchical structures is proposed based on EMsFEM. After that, the sensitivity analysis scheme of the objective function and constraint functions is given, based on which the Method of Moving Asymptotes (MMA) is employed to update design variables. The assumption of separation of length scales is not required in the proposed method, which avoids the disconnection between adjacent substructures. Besides, without limiting the topology and spatial distribution of substructures in advance, the concurrent topology optimization for hierarchical structures with multiple substructures can be realized using this method. The provided numerical examples verify the correctness and effectiveness of the proposed sensitivity analysis method as well as the feasibility, effectiveness and scalability of the proposed concurrent topology optimization method for hierarchical structures. Finally, the influence of the initial substructure configurations and the number of substructure types on the final configuration and mechanical performance of hierarchical structures are explored with a series of numerical examples.

Comparison of fatigue behaviour and fracture toughness of cobalt chromium alloy fabricated by casting and selective laser melting methods

Co-Cr alloys are most commonly used base metal alloy in dentistry for the fabrication of many types of metallic substructures. They gained popularity due to their good mechanical properties and low cost. There are different techniques for fabrication of Co-Cr alloys which includes casting and DMLS technique. However, change in the fabrication techniques showed variation in mechanical properties. Forty Co-Cr samples each were made from two different techniques, Casting and DMLS. Fracture toughness was done with charpy’s impact test machine and fatigue behaviour test was done with nano universal testing machine. The samples were later observed under stereo electron microscope to assess the kind of failure. Unpaired t test revealed that there was statistically significant difference between two different groups. The mean difference of fracture toughness in Casting group was higher when compared with DMLS group. The number of fatigue cycles were higher in DMLS group than the casting group. Within the limitations of this in vitro study, casting group showed higher fracture toughness when compared to DMLS group, whereas fatigue limit was higher in DMLS group than casting group.

Flares, Jets, and Quasiperiodic Outbursts from Neutron Star Merger Remnants

Using numerical relativity simulations with a subgrid dynamo prescription to generate strong initial magnetic fields, we investigate the possibility of launching a jet-like outflow from the hypermassive neutron star (HMNS) during the early stages of the merger, prior to the remnant’s collapse to a black hole. We demonstrate that buoyant instabilities in the strongly magnetized HMNS can lead to a periodic emission of powerful electromagnetic flares shortly after the merger. These are followed by a collimated mildly relativistic outflow. Both types of outflows feature quasiperiodic kilohertz substructure. These early-time outflows may power precursors to short-duration gamma-ray bursts (sGRBs) or in some cases the entire sGRB. While the overall temporal power spectrum we find broadly agrees with the one recently reported for quasiperiodic oscillations in the sGRB GRB910711, our simulations suggest that the periodic electromagnetic substructure is dominated by magnetohydrodynamic shearing processes rather than correlating with the corresponding postmerger gravitational-wave signal.

Influence of Plastic Deformation on the Accumulation of the Average Scalar Dislocation Density and Its Components pS and pG in Cu-Mn Alloys

The development and progress of the physical science of strength makes it possible to formulate the main aspects based on dislocation physics. This article describes the current state of this issue in the framework of a multilevel approach. It considers the patterns of accumulation of dislocations in a material after various degrees of deformation. The main mechanism of hardening of a metal polycrystal is the accumulation of dislocations in its grains, and the main hardening parameter is the average scalar dislocation density. The scalar dislocation density is divided into components: the density of statistically stored (pS) and the density of geometrically necessary (pG) dislocations. Transmission diffraction electron microscopy (TEM) is used to study the stages of the development of types of dislocation substructure (DSS) in Cu-Mn alloys depending on the concentration of the alloying element during active plastic deformation. Polycrystalline alloys were investigated over a wide concentration range from 0.4 to 25 atomic percent Mn. A number of parameters of the dislocation substructure are measured from micrographs obtained in an electron microscope: the average scalar density of dislocations <p>, the density of statistically stored (pS) and geometrically necessary (pG) dislocations, the curvature-torsion of the crystal lattice (х), the density of microbands (b), density of dangling subboundaries (Msub). A sequence of transformations of DSS types with an increase in the degree of deformation and the value of the second element to form the type of substructure and its parameters is established. The influence of the concentration of the second element and the grain size on the average scalar density of dislocations and its components is experimentally determined. The presence of misorientations in the substructure during deformation is based on the measurement of these parameters using the TEM method.

Substructure parameters in deformed Cu – Mn alloys with a FCC lattice

Development and successes of the physical science of strength and durability allow us to formulate the main aspects of dislocation physics. In this paper, the current state of this issue is considered within the framework of a multilevel approach – patterns of dislocations accumulation in the material after deformation with various degrees. The main mechanism of hardening of a metallic polycrystal is the dislocations accumulation in its grains, and the main parameter of hardening is the average scalar density of dislocations. The scalar dislocation density is divided into components: the density of statistically stored (ρS ) and the density of geometrically necessary (ρG ) dislocations. Transmission diffraction electron microscopy (TEM) is used to study the stages of development of types of dislocation substructure (DSS) in Cu – Mn alloys depending on concentration of the alloying element during active plastic deformation. Polycrystalline alloys were studied in a wide concentration range: from 0.4 to 25 % Mn (at.). A number of dislocation substructure parameters were measured using the images obtained on an electron microscope: the average scalar density of dislocations <p>, the density of statistically stored (ρS ) and geometrically necessary (ρG ) dislocations, the curvature-torsion of the crystal lattice (χ), the density of microstrips (Рstrips ), the density of ragged sub-boundaries (Мrag.bound. ). The authors established the effect of the sequence of DSS types transformations with an increase in the degree of deformation and the second element quantity on formation of the type of substructure and its parameters. Influence of concentration of the second element and the grain size on the average scalar density of dislocations and its components was experimentally determined. The presence of disorientations in the substructure during deformation is based on the measurement of these parameters by the TEM method.

Progressive collapse resistance of unsymmetrical steel sub-structure under a middle column-removal scenario

This paper presents an investigation on progressive collapse resistance of a type of unsymmetrical steel sub-structure. The sub-structure which consists of box-beam, H-beam and tube column is extracted from the practical project. In order to examine the effect of the unequal geometrical parameters, three specimens with different span ratio of box-beam to H-beam and depth ratio of H-beam to box-beam were designed for Pushdown test. Moreover, a numerical analysis is carried out, wherein the finite element models are established by ABAQUS, and the validation is conducted by the comparison with experimental results. Furthermore, a Beam Supporting Transfer Structure (BSTS) is considered in parametric studies, aiming to further explore the influence of extra load resulting from BSTS on unsymmetrical structure. The experimental results indicate that the ratios expressed for the span and depth under different value can easily change the overall resistance of the unsymmetrical structure, especially in the First Peak Load (FPL), Ultimate Failure Load (UFL). Regarding mechanical behavior of components, when the depth ratio is equal to 0.8, span ratio decreases from 1.5 to 1, the Catenary Action (CA) of H-beam and Flexural Action (FA) of box-beam display more sensitive to the variation of span ratio than other key results. Similarly, when the span ratio is equal to 1.5 depth ratio increases from 0.8 to 1, the FA of H-beam and CA of box-beam show more sensitive to the variation of depth ratio than other key results. Moreover, the UFLs of three specimens are observed as the ultimate load resistance in experiment, which is due to the development of the CA of beams and large residual resistance provided by the FA of box-beam. Ultimately, an advice of the span ratio and depth ratio for structure design is proposed.

ФОРМИРОВАНИЕ МАРШРУТА МАГИСТРАЛЬНОЙ ТРЕЩИНЫ РАЗРУШЕНИЯ В МНОГОУРОВНЕВОЙ СТРУКТУРЕ КОНГЛОМЕРАТНЫХ СТРОИТЕЛЬНЫХ КОМПОЗИТОВ

In the publication, conglomerate building composites (concrete) are identified as heterogeneous solids with a hierarchically organized spatial-geometric structure with a characteristic dimension from 10-10 to 10-1 m, with a minimum of 5-6 scale levels and three types of substructure design that differ in scale, genesis and mechanics of properties manifestation. The first type is characteristic of the macro-, meso- and microscale levels and is taken in the form of a two-component “construction” of a spatially continuous matrix and discrete solid and gaseous (macropores) inclusions deterministically and stochastically distributed in it; the second type refers to the submicro-, ultra-micro- and nanoscale levels and is believed to be in the form of a “microscale spatial structure” of new formations of a cementitious substance from consolidated individual crystalline differences; the third type, finally, corresponds to the atomic-molecular structure of new formations of the cementing substance. Characteristics of the distinguished types of substructures are given according to the scale of their components, the peculiarities of formation, the mechanics of manifestation of properties, design criteria and means of synthesis of each substructure. The patterns of formation of the fracture route in substructures of all types and substances of each scale level are analyzed. In this case, the development of the stress-strain state of the conglomerate composite according to the principle of energy dissipation, localization and increase (concentration) of stress is realized in the direction from the macro- to the atomic-molecular level of the structure of the composite, and the destruction itself and, accordingly, the formation of the crack route in time and in space of the composite passes in the direction from the atomic-molecular level to the macrolevel in a cascade through all intermediate structural levels. Within the framework of an integrated mechano-physico-chemical approach, the place of thermofluctuation theory (fracture physics) at the stages of breaking single atomic-molecular bonds and crack mechanics at the stages of development of micro- and macrodamage is shown. The possibilities of using theoretical principles of crack route formation to formulate and solve practical problems of designing and synthesizing optimal structures of conglomerate building composites are discussed.

Using wavelets to capture deviations from smoothness in galaxy-scale strong lenses

Modeling the mass distribution of galaxy-scale strong gravitational lenses is a task of increasing difficulty. The high-resolution and depth of imaging data now available render simple analytical forms ineffective at capturing lens structures spanning a large range in spatial scale, mass scale, and morphology. In this work, we address the problem with a novel multiscale method based on wavelets. We tested our method on simulated Hubble Space Telescope (HST) imaging data of strong lenses containing the following different types of mass substructures making them deviate from smooth models: (1) a localized small dark matter subhalo, (2) a Gaussian random field (GRF) that mimics a nonlocalized population of subhalos along the line of sight, and (3) galaxy-scale multipoles that break elliptical symmetry. We show that wavelets are able to recover all of these structures accurately. This is made technically possible by using gradient-informed optimization based on automatic differentiation over thousands of parameters, which also allow us to sample the posterior distributions of all model parameters simultaneously. By construction, our method merges the two main modeling paradigms – analytical and pixelated – with machine-learning optimization techniques into a single modular framework. It is also well-suited for the fast modeling of large samples of lenses.

Margin Adaptation of Zirconia and Sintron Copings before and after Firing with Two Different Types of Porcelain

Introduction: Given the surge in the restoration of infrastructures with zirconia and sintron and the use of different porcelain on them and the lack studies on marginal adaptation in different situations, this study aimed to evaluate the marginal gap before and after porcelain firing.
 Materials & Methods: This cross sectional experimental laboratory research was performed in 2019 in the Transgenesis research center, Isfahan (Khorasgan) Branch, Islamic Azad University, where 40 abutments were divided into two groups of 20 with two types of substructures (zirconia and soft presintered chrome-cobalt alloy (Syntron) AmannGirrbach, Koblach, Austria)) then ,each group was subdivided into two porcelain subgroup of ten (noritake and creation).Marginal gap was evaluated by stereomicroscope before and after porcelain firing .Data was gathered and analyzed by means of one way and two-way ANOVA (α = 0.05).
 Results: The difference observed between marginal gap in studied groups was statistically significant (p value < 0.05). But marginal gap in respect to the type of porcelain did not show a significant difference between the groups (p value = 0.214). The lowest amount of change after firing with porcelain was related to the Syntron substructure group with Noritake porcelain, which was significantly different from the two zirconia frame groups (p value = 0.045), (p value = 0.006).
 Conclusion: In this research after porcelain firing, sintron showed better results compared to zirconia regardless of porcelain type.

Prediction of Residential Slab Foundation Movement Through a Finite Element-Based Deep Learning Algorithm

Deep learning networks were employed to predict the maximum differential deflection of stiffened and waffle rafts due to reactive soil movements, Δmax. Four deep learning networks were used to predict Δmax, these are (1) stiffened rafts on shrinking soil, (2) stiffened rafts on swelling soil, (3) waffle rafts on shrinking soil, and (4) waffle rafts on swelling soil. The deep learning models were used to create design lines, which showed that both soil and structural features strongly influence the stiffened rafts. In contrast, waffle rafts showed a strong dependence on soil features in shrinking soils and beam depth in swelling soils. This demonstrates that the finite element-based deep learning networks captured the effect of the embedment of the beams. The results of the deep learning models led to non-linear design curves, which are disparate from the suggested standard Australian design. These results suggest that increasing the value of beam depth can have a positive or negative impact on the global residential slab depending on the type of substructure and whether the founding reactive soil is shrinking or swelling. Global sensitivity analyses of the deep learning models showed that for stiffened rafts on shrinking soil, the slab length, slab width and active depth zone of reactive soil had the most significant influence on Δmax, whilst for stiffened rafts on swelling soil, the primary drivers are ground movement, beam depth, and slab width. The prediction of Δmax for waffle rafts on shrinking soil was driven by the surface characteristic and mound movements, and the active depth zone, whilst waffle rafts on swelling soil was driven by the beam depth. Overall, the finite element-based deep learning showed the capacity to estimate Δmax in both shrinking and swelling design scenarios for different types of residential footing systems to further understand the characteristic behaviour of shallow residential slab foundations on reactive soils leading to improved designs.

Evaluating operational strategies for the installation of offshore wind turbine substructures

The construction of offshore wind farms requires solving more and more complex logistical problems due to the increasing sizes of turbines and changing environments. In particular, the installation of substructures requires attention due to their significant impact on capital expenditures and the limited literature and guidelines available. In this paper, we develop a decision support tool consisting of a discrete-event simulation that allows for comparing strategies for the installation of offshore wind turbine substructures in terms of time and costs. We identify several combinations of transportation and installation strategies for monopile and for jacket substructures. The differentiation is based on the deployed vessels and the installation sequence of the components. The strategies are applied to the case of a wind farm in the North Sea. For both substructure types, we find that strategies involving a second installation vessel result in the shortest installation times, and those in which the installation vessel(s) take(s) care of both transportation and installation result in the lowest costs. Additionally, we quantify the performance increases as a result of a reduction of the most prominent bottlenecks and the sensitivity of the project performance to the start date. Finally, the results are discussed in relation to future market and technological developments in the field.