Following the preceeding paper which has dealt with theoretically the stresses in the vicinity of a square hole with rounded corners in a cylindrical shell, results of the experimental study of the problem carried out photoelastically are reported. The photoelastic models used were made by the technique of centrifugal casting. The load applied are axial compression, tension or bending moment. Using the results of single layer and double layer models, not only membrane stresses but also bending stresses were measured. Displacements perpendicular to the surface near the hole were also measured. Further, a model with a pach type stiffener was tested. All the results obtained are compared with the results of theoretical analyses and are discussed.
The analytical method decribed in the authors' previous paper is utilized to calculate the elastic moduli of unidirectional fiber-reinforced composites modelled by a square array acking of fibers. A π/4-rotated model of the psquare array isconsidered to calculate in-transverse-plane shear modulus for convenience of using a Fourier cosine series. Numerical results show that elastic symmetry of a composite modelled by a square array is the same as tetragonal crystal class. The transverse elastic moduli, ET, GTT, and νTT, varyin the transverse plane when such a symmetry exists, whereas the longitudinal shear modulus, GLT, is constant. The average values of those moduli, except for GLT, are very close to the corresponding values for the hexagonal array. Those results are almost independent of material and geometrical parameters. Off-axis properties are also obtained using independent moduli.
An experimental investigation was performed on the induced side force due to the aerodynamic interference between the wings of cruciform wing arrangement in incompressible flow. Measurements show that the induced side force is approximately proportional to α3 sin4φ, where α and φ are an included angle and an angle of roll. respectively. It is important to note that this trend agrees with the prediction based on the the lifting line theory. In addition, measurements at very high included angle were made to study the effect of the separeted flow along wings on the side force.