Determination of the response of coated fabrics under biaxial stress: comparison between different test procedures

The biaxial response of a PVC-coated polyester fabric is investigated using three different test procedures. The influence of the test procedure on the experimental data is discussed. A new approach based on a response domain is proposed

Design tools for inflatable structures

This paper shows different tools and approaches that can be useful for the definition of the design of pneumatic structures. Some of these tools have been applied for the design of a Tensairity® hull

Numerical investigation of the structural behaviour of a deployable tensairity beam

This paper investigates numerically the load bearing behaviour of a deployable Tensairity beam. More precise, it studies the influence of the cables that connect the upper and lower strut of the deployable Tensairity beam on its load bearing behaviour. Finite element analysis shows that these cables are pretensioned when the airbeam is inflated. When both diagonal and vertical cables are present, only the vertical cables become tensioned. These tensioned cables are able to take compressive forces, by the same amount as their initial pretension. This has as result that these cables avoid the hinges to deflect under compression. Or in other words, the pretensioned cables ‘block’ the hinges. Once the external load has reached the value whereby the value of the pretension becomes zero in at least one cable, the hinge is not blocked or supported anymore by this cable. The hinge will experience larger displacements and the stiffness of the deployable Tensairity beam decreases

Energetics of rocked inhomogeneous ratchets

We study the efficiency of frictional thermal ratchets driven by finite frequency driving force and in contact with a heat bath. The efficiency exhibits varied behavior with driving frequency. Both nonmonotonic and monotonic behavior have been observed. In particular the magnitude of efficiency in finite frequency regime may be more than the efficiency in the adiabatic regime. This is our central result for rocked ratchets. We also show that for the simple potential we have chosen, the presence of only spatial asymmetry (homogeneous system) or only frictional ratchet (symmetric potential profile), the adiabatic efficiency is always more than in the nonadiabatic case.Comment: 5 figure

Multiple current reversals in forced inhomogeneous ratchets

Transport properties of overdamped Brownian paricles in a rocked thermal ratchet with space dependent friction coefficient is studied. By tuning the parameters, the direction of current exhibit multiple reversals, both as a function of the thermal noise strength as well as the amplitude of rocking force. Current reversals also occur under deterministic conditions and exhibits intriguing structure. All these features arise due to mutual interplay between potential asymmetry,noise, driving frequency and inhomogeneous friction.Comment: 6 figure

An analytical model for Tensairity girders

p. 2771-2779An analytical model for the deflection of a symmetric, spindle shaped Tensairity girder under homogenous load is proposed which can be solved analytically. The results are compared to FEM predictions for a specific Tensairity girder. Further simplifications of the analytical solution lead to a simple relation for the deflection of the Tensairity girder, which reveals the importance of the elasticity of the chords relative to the air pressure in the inflated hull. Such simple models are crucial to understand the basic principles of Tensairity and provide the engineer with easy rules to estimate the load-deflection behaviour of this new light weight structure.Luchsinger, RH.; Teutsch, U. (2009). An analytical model for Tensairity girders. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/662

Determination of the response of coated fabrics under biaxial stress: comparison between different test procedures

The biaxial response of a PVC-coated polyester fabric is investigated using three different test procedures. The influence of the test procedure on the experimental data is discussed. A new approach based on a response domain is proposed

Design tools for inflatable structures

This paper shows different tools and approaches that can be useful for the definition of the design of pneumatic structures. Some of these tools have been applied for the design of a Tensairity® hull

Morphological control: Applications on different scales exploiting classical and statistical mechanics

We present three case studies in which we discuss conceptual and technical aspects of the application of morpholoigcal computation in medical and/or chemical contexts. Up to now, most implementations of morphological computing take profit of classical mechanics and so does one of ours (an inflatable support system for patients with movement impairments). The two other case studies deal with processes and devices on the micrometer scale (self-assembled chemical micro-reactors and models of induced repair in radio-oncology). We use these examples to introduce the notion of embodied process control and discuss how the role taken by classical mechanics in systems on the macro-scale can be adopted by statistical mechanics in case of implementations on the micrometer scale