Studies of implicit and explicit solution techniques in transient thermal analysis of structures

Technical Report · Sun Aug 01 04:00:00 EDT 1982

OSTI ID:6223550

Adelman, H M; Haftka, R T; Robinson, J C

Studies aimed at an increase in the efficiency of calculating transient temperature fields in complex aerospace vehicle structures are reported. The advantages and disadvantages of explicit and implicit algorithms are discussed and a promising set of implicit algorithms with variable time steps, known as GEARIB, is described. Test problems, used for evaluating and comparing various algorithms, are discussed and finite element models of the configurations are described. These problems include a coarse model of the Space Shuttle wing, an insulated frame test article, a metallic panel for a thermal protection system, and detailed models of sections of the Space Shuttle wing. Results generally indicate a preference for implicit over explicit algorithms for transient structural heat transfer problems when the governing equations are stiff (typical of many practical problems such as insulated metal structures). The effects on algorithm performance of different models of an insulated cylinder are demonstrated. The stiffness of the problem is highly sensitive to modeling details and careful modeling can reduce the stiffness of the equations to the extent that explicit methods may become the best choice. Preliminary applications of a mixed implicit-explicit algorithm and operator splitting techniques for speeding up the solution of the algebraic equations are also described.

• Research Organization: National Aeronautics and Space Administration, Hampton, VA (USA). Langley Research Center
• OSTI ID: 6223550
• Report Number(s): N-8231646; NASA-TP-2038; L-15245
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
AIRCRAFT
ALGORITHMS
ENERGY TRANSFER
FINITE ELEMENT METHOD
HEAT TRANSFER
MATHEMATICAL LOGIC
NUMERICAL SOLUTION
SPACE VEHICLES
STRUCTURAL MODELS
THERMAL ANALYSIS
VEHICLES