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This work explores the properties of four‐noded quadrilateral elements for which integration is carried out using low‐order integration rules, based on one‐point integration over subelements making up the quadrilaterals. The purpose is to identify those rules which lead to elements having the desirable properties of high coarse‐mesh accuracy, and stability in the incompressible limit. A two‐point rule is investigated in detail, as is its counterpart for problems of incompressible media, in which the volumetric term is integrated using a one‐point rule. Numerical results indicate that the new elements perform well in general when compared with existing enhanced strain or equivalent elements, and appear to be particularly efficient in cases in which meshes are severely distorted.

THE highly complex character of the gust‐load problem and the lack of knowledge of gust structure have led to the general use of gust‐strength criteria for aeroplane wings that are based on the concept of a “sharp‐edged” gust in which the aerodynamic phenomena are assumed to obey the laws of steady flow.

There are three lateral dynamic attitudes, delineated by rolling, yawing, and sideslipping. It is possible to solve for the pressures on the rolling wing by quasi‐steady analysis. This approach is, however, inapplicable for the yawing or sideslipping wing, and it is with the latter two cases that this paper deals.

The effect of structural damping on panel flutter has received little treatment in the literature but the available information suggests that such an effect may be destabilizing. By considering a two‐dimensional, simply‐supported panel and using linear piston theory for the aerodynamic forces an analysis is presented in which the effect of hysteretic structural damping is considered. The main emphasis is on flat unbuckled panels, although a brief investigation of buckled panels is also presented, and it is concluded that there is an interdependence of structural and aerodynamic damping, which in the range of Mach numbers for which piston theory is valid, shows the destabilizing effect of structural damping. This effect is apparently more pronounced at high altitudes. A comprehensive bibliography of panel flutter is also included.

A paper by James George of the Civil Aeronautics Administration entitled “Development of Stall Warning Indicators”, covered three distinct types of stall warning devices. Two of these instruments will be commercially available in the near future. These will function successfully under all flight conditions except when ice has accumulated on the wings, and are considered suitable for use on private‐owner type aircraft since such aircraft are seldom involved in stall accidents where ice is a factor. The continuing programme involves the development of the third device suitable for use on existing air‐carrier type aircraft which will obtain an adequate Warning margin even when the wings are “iced up”. The results of wind tunnel and flight tests involving all three devices are presented and the entire problem is discussed in detail.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics, and publications of other similar research bodies as issued

A bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view is given. The bibliography at the end of the paper contains 1,726 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1996‐1999.