Active membranes:3D printing of elastic fibre patterns on pre-stretched textiles

There has been a steady growth, over several decades, in the deployment of fabrics in architectural applications; both in terms of quantity and variety of application. More recently 3D printing and additive manufacturing have added to the palette of technologies that designers in architecture and related disciplines can call upon. Here we report on research that brings those two technologies together - the development of active membrane elements and structures. We show how these active membranes have been achieved by laminating 3D printed elasto-plastic fibres onto pre-stretched textile membranes. We report on a set of experiments involving one-, two- and multi-directional geometric arrangements that take TPU 95 and Polypropylene filaments and apply them to lycra textile sheets, to form active composite panels. The process involves a parametrised design, actualized through a particular fabrication process. Our findings document the investigation into mapping between the initial two-dimensional geometries and their resulting three-dimensional doubly-curved forms, as well as accomplishments and products of the resulting, partly serendipitous, design process

Parameter identification in stationary groundwater flow problems in drainage basins

AbstractWe discuss the recovery of some parameters in an elliptic boundary value problem, which models a specific stationary flow problem in drainage basins, by using the measured values of the hydraulic head in discrete points through the physical domain. The underlying direct problem is the one considered by Tòth (J. Geophys. Res. 67 (1962) 4375; 67 (1963) 4795), among others. The inverse problem is solved by means of the Levenberg–Marquardt method (in: G.A. Watson (Ed.), Numerical Analysis, Lecture Notes in Mathematics, Vol. 630, Springer, Berlin, New York, 1977, pp. 105–116). We also show how the infinite element method allows the identification of the far field value of the hydraulic head

Solution of inverse problems in contaminant transport with adsorption

Abstract. In this paper, solution of inverse contaminant transport problems is studied, including nonlinear sorption in equilibrium and non-equilibrium mode. A precise numerical solver for the direct problem is discussed. The method is based on time stepping and operator splitting with respect to the nonlinear transport, diffusion and adsorption. The nonlinear transport problem corresponds to a multiple Riemann problem and is solved by modified front tracking method. The diffusion problem is solved by a finite volume scheme and the sorption part is solved by an implicit numerical scheme. The solution of the inverse problem is based on an iterative approach. The gradient of the cost functional with respect to the determined parameters is constructed by means of solution of the corresponding adjoint system. Numerical examples are presented for a 1D situation and for a dual-well setting with steady-state flow between injection and extraction wells. 1. Mathematical model Contaminant transport with dispersion and adsorption is modelled by the following system: (1) ∂tϕ(C) + div(¯v · C − D∇C) = − θ

Bench-scale centrifuge testing to determine the hydraulic conductivity of clayey soils

The purpose of this research is to validate a mathematical model for flow through saturated and unsaturated porous media using a bench-scale centrifuge for an accurate determination of the hydraulic conductivity (function of the saturation degree of a soil) within a limited time at a reasonable price. The aim of this paper is to show preliminary results of this investigation where the validation and calibration of the mathematical model is performed determining the hydraulic conductivity of saturated porous media, such as kaolin clay and glass porous filters, with a bench-scale centrifuge