Many natural composite materials have evolved to wrinkle in response to certain stimuli: The eye of the squid is lined with wavy layers of silvery reflectors that give it a silvery sheen. In the cell walls of many plants, wrinkles allow expansion without strain. Finally, the inner lining of arteries contain wrinkled lamellae that can be indicators of coronary heart disease, and can serve as markers for the condition.
Given these examples from nature, scientists say that understanding the mechanisms by which materials internally wrinkle could help in creating new, responsive materials for use in chemical sensing, medical diagnostics and optical and acoustic wave control.
Now researchers at MIT have identified the mechanics involved in the wrinkling of thin interfacial layers within soft composite materials, and developed a model based on material properties and geometry to predict how wrinkled an internal layer may become, given its stiffness and width. The researchers also fabricated composite materials using multi-material 3-D printing, and observed the wrinkling and instability pattern — results that were correctly predicted by their model.
Narges Kaynia, a graduate student in mechanical engineering at MIT, says the model may serve as a blueprint for developing new composite materials with reversibly wrinkling interfaces. Continue reading the article on MIT News. photo courtesy of Narges Kaynia and Yaning Li