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Tamma, K. K.

Publications and source records attributed to Tamma, K. K..

10 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Further development towards a new virtual-pulse time integral methodology for general nonlinear transient thermal analysis

New developments describing the theoretical basis towards an effective virtual-pulse time integral procedure are presented for general nonlinear transient heat transfer problems. To validate the proposed methodology of computation, numerical test examples are given and comparisons are drawn with the implicit second-order accurate Crank-Nicolson technique. The proposed method shows superior or improved accuracy and stability characteristics for the models tested.

Tamma, K. K.↗
NASA NTRS1991

Applicability/evaluation of flux based representations for linear/higher order elements for heat transfer in structures - Generalized gamma(T)-family

The applicability and evaluation of a generalized gamma(T) family of flux-based representations are examined for two different thermal analysis formulations for structures and materials which exhibit no phase change effects. The so-called H-theta and theta forms are demonstrated for numerous test models and linear and higher-order elements. The results show that the theta form with flux-based representations is generally superior to traditional approaches.

Namburu, R. R.↗
NASA NTRS1989

Prediction of thermal-stress and deformations due to phase change in solidifying objects via flux/stress based finite element representations

The paper presents numerical simulations for the prediction of thermal-stress and deformation fields resulting from phase change in solidifying bodies employing new finite element representations. The formulations herein demonstrated provide different perspectives and physical interpretation for the modeling/analysis of thermo-mechanical problems and possess several inherent advantages. In comparison to traditional approaches for solving similar problems, the paper employs new flux/stress based representations to enhance the overall effectiveness. Comparative numerical applications validate applicability of the formulations for predicting the temperature induced deformations and stresses resulting from effects due to phase change.

Tamma, K. K.↗
NASA NTRS1986

Computational aspects of heat transfer in structures via transfinite element formulations

The paper presents a generalized Transform Method based Finite Element methodology for thermal analysis with emphasis on the computational aspects of heat transfer in structures. The purpose of this paper is to present an alternate methodology for thermal analysis of structures and therein outline the advantages of the approach in comparison with conventional finite element schemes and existing practices. The overall goals of the research, however, are aimed first toward enhanced thermal formulations and therein to provide avenues for subsequent interdisciplinary thermal/structural analysis via a common numerical methodology. Basic concepts of the approach for thermal analysis is described with emphasis on a Laplace Transform based finite element methodology. Highlights and characteristic features of the approach are described via generalized formulations and applications to several problems. Results obtained demonstrate excellent agreement in comparison with analytic and/or conventional finite element solutions with savings in computational times and model sizes. Potential of the approach for interdisciplinary thermal/structural problems are also identified.

Tamma, K. K.↗
NASA NTRS1986

Transfinite element methodology towards a unified thermal/structural analysis

The paper describes computational developments towards thermal/structural modeling and analysis via a generalized common numerical methodology for effectively and efficiently interfacing interdisciplinary areas. The proposed formulations use transform methods in conjunction with finite element developments for each of the heat transfer and structural disciplines, respectively, providing avenues for obtaining the structural response due to thermal effects. An alternative methodology for unified thermal/structural analysis is presented. The potential of the approach is outlined in comparison with conventional schemes and existing practices. Highlights and characteristic features of the approach are described via general formulations and applications to several problems. Results obtained demonstrate excellent agreement in comparison with analytic and/or conventional finite element schemes accurately and efficiently.

Tamma, K. K.↗
NASA NTRS1981

Integrated transient thermal-structural finite element analysis

An integrated thermal structural finite element approach for efficient coupling of transient thermal and structural analysis is presented. Integrated thermal structural rod and one dimensional axisymmetric elements considering conduction and convection are developed and used in transient thermal structural applications. The improved accuracy of the integrated approach is illustrated by comparisons with exact transient heat conduction elasticity solutions and conventional finite element thermal finite element structural analyses.

Thornton, E. A.↗
NASA NTRS1981

Exact finite elements for conduction and convection

An approach for developing exact one dimensional conduction-convection finite elements is presented. Exact interpolation functions are derived based on solutions to the governing differential equations by employing a nodeless parameter. Exact interpolation functions are presented for combined heat transfer in several solids of different shapes, and for combined heat transfer in a flow passage. Numerical results demonstrate that exact one dimensional elements offer advantages over elements based on approximate interpolation functions.

Thornton, E. A.↗
NASA NTRS1981

Integrated transient thermal-structural finite element analysis

An integrated thermal-structural finite element approach for efficient coupling of transient thermal and structural analysis is presented. New integrated thermal-structural rod and one dimensional axisymmetric elements considering conduction and convection are developed and used in transient thermal-structural applications. The improved accuracy of the integrated approach is illustrated by comparisons with exact transient heat conduction-elasticity solutions and conventional finite element thermal-finite element structural analyses. Results indicate that the approach offers significant potential for further development with other elements.

Thornton, E. A.↗
NASA NTRS1981

Exact finite elements for conduction and convection

An appproach for developing exact one dimensional conduction-convection finite elements is presented. Exact interpolation functions are derived based on solutions to the governing differential equations by employing a nodeless parameter. Exact interpolation functions are presented for combined heat transfer in several solids of different shapes, and for combined heat transfer in a flow passage. Numerical results demonstrate that exact one dimensional elements offer advantages over elements based on approximate interpolation functions. Previously announced in STAR as N81-31507

Thornton, E. A.↗