Search results for " thrust"

The interation of compressional and extensional tectonics during the Sicily Chain building

2012

CONCEPTUAL DESIGN OF BOWSTRING BRIDGES WITH STRESS RIBBON TIE

2011

In this paper the conceptual design of tied-arch bridges is examined. A proposal for a particular kind of bowstring bridges, with an upper deck and a stress ribbon footbridge placed between the arch footings is discussed. The double structure allows to avoid horizontal forces into foundations when functional requirements lead to differentiate pedestrian and road traffic. After a general discussion about classical tied-arches, the main parameters involved in the design of the proposed solution are discussed and a case-study is presented.

Transition from thin- to thick-skinned tectonics and consequences for nappe formation: Numerical simulations and applications to the Helvetic nappe s…

2015

Abstract We use two-dimensional numerical simulations to study the deformation style and the formation of nappes during the shortening of basement–cover systems with half-grabens. We perform simulations with only linear and power-law viscous rheology, and also thermo-mechanical simulations with viscoelastoplastic rheology and temperature-dependent viscosities. The accumulated, area-averaged strain is calculated for the sediments, es, and for the basement, eb, to quantify the deformation style. The results show that the transition from thin-skinned dominated (es/eb > 1) to thick-skinned dominated (es/eb ≤ 1) deformation is controlled by two effective viscosity ratios: the ratio of viscosity …

The Sicilian collisional boundary. An unconventional carbonate foreland and fold and thrust belt.

2014

Tectonics vs. sedimentation during the Sicilian orogenesis. The case history of upper Miocene terrigenuous basins in the central-eastern Sicily

2014

Graphical and Analytical Quantitative Comparison in the Domes Assessment: The Case of San Francesco di Paola

2021

(1) Methods for checking the condition of monumental masonry structures can still be considered understudied. Among the different approaches available in the literature, the graphical ones have a special role, due to their simplicity and effectiveness. (2) In this work, a 2D method (Thrust Line Analysis (TLA)), the Modified Thrust Line Method (MTLM), and the 3D Membrane Equilibrium Analysis (MEA) method are compared. All methods have the same starting concept: no tensile strength, no sliding between the stone blocks, infinite compressive strength. (3) The methods are compared in terms of stress distribution (for the same—or similar—thrust line), and in terms of the Geometrical Safety Factor…

Energy minimization of single input orbit transfer by averaging and continuation

2006

AbstractThis article deals with the transfer between Keplerian coplanar orbits using low propulsion. We focus on the energy minimization problem and compute the averaged system, proving integrability and relating the corresponding trajectories to a three-dimensional Riemannian problem that is analyzed in details. The geodesics provide approximations of the extremals of the energy minimization problem and can be used in order to evaluate the optimal trajectories of the time optimal and the minimization of the consumption problems with continuation methods. In particular, minimizing trajectories for transfer towards the geostationary orbit can be approximated in suitable coordinates by straig…

Time Versus Energy in the Averaged Optimal Coplanar Kepler Transfer towards Circular Orbits

2015

International audience; The aim of this note is to compare the averaged optimal coplanar transfer towards circular orbits when the costs are the transfer time transfer and the energy consumption. While the energy case leads to analyze a 2D Riemannian metric using the standard tools of Riemannian geometry (curvature computations, geodesic convexity), the time minimal case is associated to a Finsler metric which is not smooth. Nevertheless a qualitative analysis of the geodesic flow is given in this article to describe the optimal transfers. In particular we prove geodesic convexity of the elliptic domain.

On the optimal control of the circular restricted three body problem

2011

The context of this work is space mechanics. More precisely, we aim at computing low thrust transfers in the Earth-Moon system modeled by the circular restricted three-body problem. The goal is to calculate the optimal steering of the spacecraft engine with respect to two optimization criteria: Final time and fuel consumption. The contributions of this thesis are of two kinds. Geometric, first, as we study the controllability of the system together with the geometry of the transfers (structure of the command) by means of geometric control tools. Numerical, then, different homotopic methods being developed. A two-three body continuation is used to compute minimum time trajectories, and then …

Variation in structural styles within fold-and-thrust belts: Insights from field mapping, cross-sections balancing, and 2D-kinematic modelling in the…

2021

Abstract Fold-and-thrust belts developed above an evaporite decollement host structural traps where geofluids, including hydrocarbons, can accumulate. A valid and accurate structural style intepretation is therefore crucial to understand the three-dimensional geometries in the subsurface, in order to better model geofluid reservoirs and to increase success during exploration. Here, we present a multidisciplinary approach to unravel the subsurface structural styles of the Jura fold-and-thrust belt (eastern France), combining geological mapping, from regional to outcrop scale, with cross-section balancing and 2D-kinematic forward modelling. Results show that the Jura fold-and-thrust belt is c…