Mechanical and thermal analysis of microvascular networks in structural composite panels

Aerospace-grade, quasi-isotropic composite laminate panels of IM7/977-2 carbon fiber/epoxy prepreg are cured in an autoclave with microvascular channels. The channels are created both with a stainless steel tube insert and a removable mandrel to create lined and unlined passages, respectively. The interlaminar fracture toughness is examined as a function of the channel diameter and orientation to the adjacent, unidirectional fiber plies in a double cantilever beam test. The channels allow for a heat exchange fluid to flow through the composites and facilitate thermal transport. Thermography is used to examine the steady state surface temperature profiles of the horizontally oriented panels operating with internal fluid flow and external natural convection. A two-dimensional, analytic model was developed for the surface temperature profiles to understand the thermal transport within the specimens. The framework for the design and operation of multi-channel systems is established and a case study for surface temperature control is examined.