T-elements analysis of plated on unilateral elastic Winkler-type foundation
This paper presents a hybrid–Trefftz finite element algorithm designated as fictitious load approach. Its originality resides in the formulation and practical application of concepts which make it possible to account for the unilateral contact conditions of a plate without modification of the finite element mesh. To reach this aim, the approach allows the movable interface between the contact and non–contact parts of the plate to travers any finite element subdomain. The adjustments are confined to fictitious load dependent terms, while the element stiffness matrices remain unchanged during the whole iterative process. Several numerical examples are analysed to assess the effectivity of the T–element algorithm and to compare it with some of the existing solutions of the same problem.
Some remarks on finite elements with an elliptic hole
Some issues regarding the implementation of finite elements with elliptic holes are discussed. Although the treatment of rigid body modes appears to be different for Trefftz functions satisfying boundary conditions on circular holes from those functions ensuring the satisfaction of boundary conditions on elliptic holes, the programming can be done similarly. For the investigation of the numerical performance of hole elements using a larger number of Trefftz functions, a 24-node hole element is compared to 8-node and 16-node elements. Details of the implementation issues are given.
Calculation of Complex Radiant Heat Load From Surrounding Radiator Surface Temperatures
Abstract A method for calculating the radiant heat exchange between an absorber and individual radiating components in its surroundings is reported. Radiator surface temperatures, ambient and absorber temperatures, and configuration factors for radiating components in the surroundings are used in the customary radiant heat exchange formulae. Simplified methods for calculating or estimating configuration factors for radiators of various shapes solely from angles, subtended at the absorber by the radiators are presented. The method has been verified in the laboratory under controlled conditions and has been used to advantage in the field studies. The method has advantages over the globe therometer method in certain applications.