Documents published in Scipedia

• Numerical evaluation of in-plane shear behavior of woven webbings

  E. Sosa, M. MOURE

  Materiales Compuestos (Online first).

  
  

  Abstract

  The development and construction of multilayered, high-strength membranes for large-scale inflatable structures requires understanding each layer's mechanical behavior. A typical multilayer configuration comprises a thin inner fabric layer that contains the inflation and pressurization fluid, air, or water, an intermediate fabric layer that protects the inner layer, and an external macro-fabric layer that provides mechanical strength to withstand membranal stresses resulting from the pressurization, as well as the effects of potential external forces. This macro-fabric usually comprises high-strength webbings interlaced in a plain weave pattern linked to the two inner layers at discrete connecting points. Previous experimental studies using a "picture frame" configuration have been dedicated to evaluating shear behavior to account for the drapeability of the inflatable necessary to conform to the irregularities when deployed in confined environments. While experimental evaluations provided valuable information on the shear properties of woven webbings, only a few configurations can be evaluated. This study focuses on developing a finite element simulation of the in-plane shear behavior of woven webbings manufactured with Vectran fibers. A three-dimensional simulation model is created with Simulia/Abaqus following the "picture frame" test configuration designed to produce an in-plane shearing effect from an axial force. The simulation model includes contact interactions, friction, biaxial pre-tensioning loads, and shearing effect implemented experimentally. A series of parametric studies is also conducted to assess the influence of changes in the pretension level and friction on the shear stress as a function of the angular distortion. Numerical results are compared with experimental evaluations, providing valuable insight into the shear behavior of macro-fabrics created from woven webbings.

  Abstract
  The development and construction of multilayered, high-strength membranes for large-scale inflatable structures requires understanding each layer's mechanical behavior. [...]

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• Reliability design methodology for confined high pressure inflatable structures

  E. Barbero, E. Sosa, X. Martinez, J. Gutierrez

  Engineering Structures (2013). Vol. 51, pp. 1-9

  
  

  Abstract

  A design methodology for high pressure, inflatable structures is proposed. The inflatable structure may be partially confined inside large diameter conduits and tunnels. The design addresses the main structural requirements of the system, namely, fabric strength, geometric stability, and axial stability. The proposed design methodology is based on the concept of limit states. Load and resistance factors are identified for all the stochastic variables participating in the structural design equations. A formal methodology is used to estimate the load and resistance factors from known distributions of data for each of the stochastic variables. The concepts of basis values, coverage, and confidence are used along with the analytical treatment necessary to estimate the load and resistance factors. The analysis is applied to the cases of Normal, Log-normal, and Weibull distributions of data. Material characterization and data analysis are presented for fabric strength and friction coefficient between the inflatable and the confining conduit material. The system reliability is also evaluated.

  Abstract
  A design methodology for high pressure, inflatable structures is proposed. The inflatable structure may be partially confined inside large diameter conduits and tunnels. The [...]

  • 5
  •  read