Implementation and Validation of Schapery-Rand Anisotropic Viscoelasticity Model for Super-Pressure Balloons
نویسندگان
چکیده
The thin film used for the NASA Ultra Long Duration Balloons (ULDB) shows considerable time-dependent behaviour. Furthermore, experiments on scaled ULDB balloons have revealed that wrinkles are present over a wide range of pressures. A numerical model has been developed describing the nonlinear anisotropic viscoelastic material behaviour by means of a Schapery-type model and this model has been extended to model wrinkling by means of a user-defined subroutine in the finite-element package ABAQUS. After a description of the viscoelastic modelling approach, a lobe of a 48 gore ULDB flat facet balloon is modelled and compared to experimental results. Additionally two test cases of anisotropic wrinkling are presented, one involving a flat membrane and one a cylindrical balloon structure.
منابع مشابه
Modelling of Anisotropic Viscoelastic Behaviour in Super-Pressure Balloons
Large balloon structures are made of thin anisotropic polymeric film that shows considerable time-dependent material behaviour. While the material has been fully characterised and a detailed time-dependent material description by means of a nonlinear viscoelastic Schapery material model is available, there is no suitable numerical implementation for finite element analysis. This paper presents ...
متن کاملFinancial Incentives: Only One Piece of the Workplace Wellness Puzzle; Comment on “Corporate Wellness Programs: Implementation Challenges in the Modern American Workplace”
In this commentary, we argue that financial incentives are only one of many key components that employers should consider when designing and implementing a workplace wellness program. Strategies such as social encouragement and providing token rewards may also be effective in improving awareness and engagement. Should employers choose to utilize financial incentives, they should tailor them to ...
متن کاملThermo-mechanical analysis of diesel engines cylinder heads using a two-layer viscoelasticity model with considering viscosity effects
Loading conditions and complex geometry have led the cylinder heads to become the most challenging parts of diesel engines. One of the most important durability problems in diesel engines is due to the cracks valves bridge area. The purpose of this study is a thermo-mechanical analysis of cylinder heads of diesel engines using a two-layer viscoelasticity model. The results of the thermo-mechani...
متن کاملVenus Aerial Platform Options Reconsidered
Some limitations of using super-pressure balloons for probing the middle atmosphere of Venus are discussed. In particular, the accuracy of derived vertical wind velocities obtained from the VEGA flights is questioned. Concerns about using baseline superpressure balloons to achieve circumnavigation of Venus are raised. Alternatives to super-pressure balloons are reconsidered. To acquire long dur...
متن کاملAn Exact Solution for Kelvin-Voigt Model Classic Coupled Thermo Viscoelasticity in Spherical Coordinates
In this paper, the classic Kelvin-Voigt model coupled thermo-viscoelasticity model of hollow and solid spheres under radial symmetric loading condition is considered. A full analytical method is used and an exact unique solution of the classic coupled equations is presented. The thermal and mechanical boundary conditions, the body force, and the heat source are considered in the most general fo...
متن کامل