This paper deals with the dynamic stability of cross-ply laminated cylindrical shells under impact axial compressive load and external pressure. First, the motion of cylindrical shells under impact axial compressive load and external pressure is defined as axially symmetric motion. Following this definition, certain perturbations are superimposed on this motion, and their effect on the behavior of a shell is investigated. The symmetric state of motion of the shell is stable if the perturbations remain bounded. The solutions for the prebuckling motion and perturbed motion are obtained by Galerkin’s method. Stable regions are determined using Mathieu’s equation. The inevitability of dynamically unstable behavior is proved analytically, and the effects of various factors, such as combined loads ratio, number of layers, stacking sequences and dynamic unstable mode, are clarified.

In recent years, the barrier free concepts have been applied to more and more buildings and facilities. However, it is hard to completely implement the concept for existing ones. For most wheeled equipment and robots, a step and stairs are the difficult places. To solve this problem, we considered it was effective to develop the vehicle robot which can go up and down stairs by itself. Though legged robot is one of the best solutions, it requires powerful actuators and well thought mechanism. A crawler vehicle is also suitable, however, making crawler tracks is not so easy and skid motion may occur on contact planes. We propose new wheeled robot using revolving and rotating sub wheels and a telescopic body. In this paper, we will show the design requirement, mechanical designs and results of evaluation experiments.

An omnidirectional mobile vehicle created with Mecanum wheels does not easily negotiate stepped terrain, because the small slanted freely moving wheels in the Mecanum wheel rotate at the step edge and cannot obtain a grip sufficient for climbing. We developed two types of driving wheel mechanisms based on the Mecanum wheel. One is a hybrid that combines a larger grouser wheel with a smaller Mecanum wheel with a synchronized peripheral velocity and vertically adjustable central shaft. The other comprises a split Mecanum wheel where the halves shift back and forth. The radius of the grouser wheel hybrid must be carefully designed so that the grouser can produce an adequate grip at a low position for reliable transition to the frictional grip of the Mecanum wheel. Similarly, for the split Mecanum wheel, the horizontal shift distance must be carefully determined so that the grip of the edge of one half is maintained until an adequate grip can be obtained by the other half of the wheel. Experimental robots were built with Mecanum wheels 152mm in diameter to demonstrate both wheel types. These robots showed good performance by negotiating a 100mm step (grouser type) and a 70mm step (split type).

Manufacturing has been required to reduce greenhouse gases (GHG) to deal with global warming. GHG emissions and procurement costs for a virgin material production depend on not only material types and weight determined at a product design phase but also manufactured countries because of its energy mix of the electric power. Then, product designers with multiple of design considerations need to take into account of both GHG emissions and procurement cost in selecting types of materials for each part. To visualize GHG emissions and procurement costs, an estimation method based on life cycle inventory (LCI) database with the Asian International Input-Output Table has been developed. However, the estimation method often causes longer estimation time and errors for inputting data throughout the estimation processes because the method requires to refer to several different databases manually. This study focuses on assembly products/materials produced in 9 countries including Japan, and develops a decision support tool for GHG emissions and procurement costs with material recommendation by the LCI database using Asian International Input-Output Table. The developed tool enables to estimate GHG emissions and procurement cost simultaneously and automatically for each part by only inputting its material type and weight. Moreover, the material recommendation function suggests alternative materials based on reduction targets of GHG emissions and procurement costs. First, LCI database is introduced to estimate GHG emissions and procurement costs. Next, it is described processes of automatic calculation in the developed tool and recommendation function for GHG emissions and procurement costs. Finally, user tests are conducted to validate the developed tool.