A new model is proposed to accurately predict the wrinkling and collapse loads of a membrane inflated beam.In this model,the pressure effects are considered and a modified factor is introduced to obtain an accurate prediction.The former is achieved by modifying the pressure-related structural parameters based on elastic small strain considerations,and the modified factor is determined by our test data.Compared with previous models and our test data,the present model,named as shell-membrane model,can accurately predict the wrinkling and collapse loads of membrane inflated beams.
This paper extends Le van's work to the case ofnonlinear problem and the complicated configuration. Thewrinkling stress distribution and the pressure effects are alsoincluded in our analysis. Pseudo-beam method is presentedbased on the inflatable beam theory to model the inflatablestructures as a set of inflatable beam elements with a pre-stressedstate. In this method, the discretized nonlinearequations are given based upon the virtual work principlewith a 3-node Timoshenko's beam model. Finite elementsimulation is performed by using a 3-node BEAM 189 elementincorporating ANS YS nonlinear program. The pressureeffect is equivalent included in our method by modifyingbeam element cross-section parameters related to pressure.A benchmark example, the bending case of an inflatable cantileverbeam, is performed to verify the accuracy of our proposedmethod. The comparisons reveal that the numericalresults obtained with our method are close to open publishedanalytical and membrane finite element results. The methodis then used to evaluate the whole buckling and the load-carryingcharacteristics of an inflatable support frame subjectedto a compression force. The wrinkling stress and regioncharacteristics are also shown in the end. This method givesbetter convergence characteristics, and requires much lesscomputation time. It is very effective to deal with the whole load-carrying ability analytical problems for large scaleinflatable structures with complex configuration.
Changguo Wang Huifeng Tan Xingwen Du Center for Composite Materials,Harbin Institute of Technology, 150001 Harbin, China
