TPF-C Technology Plan - Exoplanet Exploration Program - NASA

Integrated Modeling and Model Validation
Fundamentally integrated analyses are supported via a set of scalar, 1-D, and 2-D finite
elements having both thermal and structural properties. Though one might argue that
such development reproduces that which is already available commercially, having an
element library that includes, for example, a hierarchical set of 2-D shell elements (linear,
quadratic, cubic) with point, edge, and surface structural and thermal loading capabilities
readily lends itself to complementary activities. Opportunities for benchmarking,
test/analysis correlation, and error investigation that would be impossible were the
underlying code available only in a proprietary, closed-source form. Recent examples
include investigation of through-thickness temperature gradients and the use of higherorder
elements to describe optical surfaces for higher-quality optical aberration
calculation.
• Nonlinear transient heat transfer:
Making extensive use of the preceding components, an extremely high-precision solution
procedure has been written at the hosting level with externalized controls for adaptive
time-stepping and nonlinear convergence detection and control. Supporting
computational modules include routines for automated vehicle orbit positioning, graybody
diffuse view factor calculations (specular exchange coefficients are currently under
development), automatic computation of Earth albedo and/or solar flux loads (including
re-reflection effects) and radiation exchange matrix generation including multiple
radiation exchange cavities. The solution approach and underlying code architecture will
allow for other embedded solution types (for example, linear structural thermal
deformation calculations for all converged heat transfer solutions), and is expected to
provide a basis for automated design sensitivity and optimization analyses for controlled
thermal systems.
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