Light-induced stress relief to improve flaw tolerance in network polymers

Journal Article · Mon Mar 15 00:00:00 EDT 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3311553· OSTI ID:21476382

Long, Kevin N; Dunn, Martin L; Scott, Timothy F; Turpin, Lucas P; Qi, H Jerry ^[1]

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1. Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309 (United States)

We demonstrate the ability to use photoactivated stress relaxation to improve flaw tolerance in network polymers. Unlike most self-healing polymers, which effectively close flaws by locally introducing healing agents (such as uncured resins), here light is used to relax elevated stresses around a flaw before it reaches a critical state, which reduces the threat that the flaw poses to the structural integrity of the material. In this study, we fabricate specimens with well-defined flaws and uniaxially stretch them to failure. By irradiating the specimens with UV light (365 nm) before failure, the nominal strain at failure is increased by 70% and the corresponding nominal stress is increased by 30% compared with nonirradiated specimens. To better understand the phenomena that occur at the multiaxial stress state at the flaw, we model the photomechanics using a recently developed finite element approach that accurately describes the light propagation, photochemistry, radical-induced network evolution, and the mechanical behavior of the material. Model predictions agree well with the experimental results and elucidate the role that photoinduced stress relaxation has on improving flaw tolerance.

• OSTI ID: 21476382
• Journal Information: Journal of Applied Physics, Vol. 107, Issue 5; Other Information: DOI: 10.1063/1.3311553; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
FAILURES
FINITE ELEMENT METHOD
LIGHT TRANSMISSION
PHOTOCHEMISTRY
RADICALS
RESINS
STRAINS
STRESS RELAXATION
STRESSES
ULTRAVIOLET RADIATION
VISIBLE RADIATION
CALCULATION METHODS
CHEMISTRY
ELECTROMAGNETIC RADIATION
MATHEMATICAL SOLUTIONS
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
POLYMERS
RADIATIONS
RELAXATION
TRANSMISSION