This study is a structural analysis of slewing bearings for wind turbines. The ball of a bearing delivers load while making contact with raceways of the inner and outer rings. To facilitate stress analysis of the slewing bearing, which has more balls than other types of bearing, the balls were converted into spring elements. Considering the shape of contact between balls and raceways, one, two, and three spring elements were introduced. Global finite element analysis of the bearing, with balls as spring elements, showed that the bearing experienced different degrees of deformation depending on the number of springs. Using the bearing deformation obtained from the global analysis, cut boundary constraint was applied for local contact analysis of balls and raceways. The contact stress between balls and raceways showed that more uniform stress could be achieved by increasing the number of springs.

Automatic open-parachute-device is an essential device in the field of aviation life-saving technology. In this paper, on the basic of the open-parachute-device mechanism, structure of its reliability function is given. According to its reliability indicators, considering the main failure mode and combining with similar products' reliability statistical data, analysis and design of reliability indicators are processed. Successively according to the principle of "redistribution method" and the principle of "proportional distribution method" about failure rate, the reliability indicators are calculated in detail. The results showed that the reliability indicators allocation with the "proportional distribution method" is little different from the reliability indicators allocation with the "redistribution method", but the former is more in line with the requirements. This design has a guiding significance to the product production.

This paper presents intensity calculation of the cylinder block of the underwater instrument cabin which has outer diameter of 220mm, thickness of 7.5mm, and length of 1660mm. With simplifying force of the cylinder block to the problem of elastic plane stress, its’ internal stress is calculated under internal pressure and external pressure, in the case of the simulation tests and working state. Calculations and simulation indicate that: its’ maximum internal stress exceeds the elastic yield limit at 30MPa, and the cylinder block cannot work in 3000 meters underwater. At the same time, it proves that the maximum internal stress first starts from the inwall of the cylinder block with the method of using internal pressurization test, which is consistent with the working state, but because the maximum internal stress in the test state is less than the maximum internal stress in the working state, the test method may misjudge. Finally, through calculation, it is specified that the theoretical work water depth of the cylinder block is 1300 m and the axial deformation is about 0.5 mm, radial deformation is about 0.1mm, which provides reference for the seal design.

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