The stratospheric airship is affected by the alternating high and low temperatures, the ozone, the ultraviolet radiation and other harsh conditions in the stratosphere environment. This paper studies the crack tip opening displacement (CTOD) fields and the strain distribution test method for the strain field in the stratospheric airship envelope material by uni-axial tensile experiments and the digital speckle correlation method (DSCM). For tearing tests of single edge notched (SEN) specimens, the initial weft crack is prefabricated to a length of 20 mm, and the typical brittle fracture is observed during the crack propagation process and the material specimen deformation field varies in a manner of steps. The calculation results of the displacement and the strain of the weft and warp fibers show that the mode I crack tip deformation field is accurately evaluated by the DSCM, which also displays the initial crack propagation law and the crack evolution characteristics of an SEN crack tip. The crack tip deformation curves for a large scale yielding length is obtained for the design and the deformation test of the high performance stratospheric airship envelope material.
LIU Longbin, LI Xue, LÜ Mingyun, MI Panpan, CAO Shuai
. Mode I Crack Tip Deformation Field for Stratopheric Airship Envelope[J]. Science & Technology Review, 2014
, 32(18)
: 15
-21
.
DOI: 10.3981/j.issn.1000-7857.2014.18.001
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