6 In this paper, theoretical study is carried out to investigate the general 3D short-crested 7 wave interaction with a concentric two-cylinder system. The interior cylinder is imperme8 able and the exterior cylinder is thin in thickness and porous to protect the interior cylinder. 9 Both cylinders are surface-piercing and bottom mounted. Analytical solution is derived 10 based on the linear po...

In an earlier paper we studied real laminated lattices (or Z-modules) A„, where A, is the lattice of even integers, and A„ is obtained by stacking layers of a suitable (n — l)-dimensional lattice A„_, as densely as possible, keeping the same minimal norm. The present paper considers two generalizations: (a) complex and quaternionic lattices, obtained by replacing Z-module by /-module, where J m...

1. Abstract The aim of this work is to perform hierarchical optimization [1] in laminated composite structures, considering simultaneously macroscopic and microscopic levels in the design of the structure and its material. In the macroscopic level, the optimization algorithm cares with orientations and fiber volume fractions of unidirectionally reinforced composite material layers. In the micro...

We study the optimal packing of hard spheres in an infinitely long cylinder, using simulated annealing, and compare our results with the analogous problem of packing disks on the unrolled surface of a cylinder. The densest structures are described and tabulated in detail up to D/d=2.873 (ratio of cylinder and sphere diameters). This extends previous computations into the range of structures whi...

Under conditions of lean fueling or high exhaust gas recirculation, interactions between residual cylinder gas and freshly injected fuel and air produce undesirable combustion instabilities in spark-ignition engines. The resulting dynamics can be described as noisy bifurcations of a nonlinear map and are complicated by cylinder-to-cylinder coupling. We discuss the key dynamic features relevant ...

The present paper describes dynamic modelling, results of simulation and experimental investigation of a hydraulic stepper cylinder, which find application in manipulators and robots. The method of bond graph is used for modelling of the dynamics of the considered cylinder design. First, an initial digital simulation is performed in order to calculate basic dynamic characteristics of the cylind...

Experiments were conducted to obtain the modal damping ratios of two hollow cylinders of different thicknesses of Aluminum. An electro dynamic exciter with slip table is used to excite the hollow cylinders. The hollow cylinder (unit under test) is fastened to the exciter. The exciter is placed in the horizontal direction and connected to the slip table. A control accelerometer is placed at the ...