Synthesis of Flexure Based Translational Springs

Translational springs are employed to generate desired force-displacement relationships. Conventional translational springs utilize elastic deformations of coiled spring strips to fulfill their functions. The one-dimensional motion of a conventional translational spring is produced by the three-dimensional deformation of its coiled spring strip, which is bending plus twisting of the coiled spring strip. Different from conventional translational springs, flexure based translational springs usually have simple planar monolithic structures, and are convenient to manufacture and maintain. The translation of a flexure based translational spring is from the two-dimensional elastic or recoverable deformations of its planar flexible members. The flexure based translational springs synthesized in this research are required to endure large input translations. Because of large deformation and geometric nonlinearity, flexure based translational springs face difficulties that include parasitic drift, spring stiffness deviation, and high stress in the deformed springs. The research of this paper is motivated by surmounting these difficulties. Flexure based translational springs with different arrangements are synthesized to eliminate parasitic drifts and have desired spring rates and reasonable maximum stress.

(164) Effect of a Non-leguminous Cover Crop, Tillage Practices, and Inorganic Nitrogen on Aboveground Biomass Production and Yields of Southernpea

The objective of this study was to examine how a non-leguminous cover crop, three tillage practices, and two synthetic nitrogen rates influence aboveground biomass, and yields of southernpea. The following fall–spring fertility treatments were applied using randomized complete-block design with four replications: 1) fall-0 N+abruzzi rye; spring-conventional till+0 N; 2) fall-0 N+abruzzi rye; spring-strip till+0 N; 3) fall-0 N+abruzzi rye; spring-No till+0 N; 4) fall-0 N+abruzzi rye; spring-conventional till+30 kg×ha–1 N; 5) fall-0 N+abruzzi rye; spring-strip till+30 kg×ha–1 N; 6) fall-0 N+ abruzzi rye; spring-No till+30 kg×ha–1 N. In Spring 2004, `Mississippi Purple' southernpea was drill planted in all plots. Pod yields were harvested at the fresh-market mature green stage and dry pod stage, while total vegetative dry matter was collected at the mature green stage. Optimal aboveground biomass (32.7 g/plant) was produced by fall-0 N+abruzzi rye; spring-strip till+30 kg×ha–1 N treatment, while maximum fresh-market pod yield (4.9 Mg×ha–1) and dry pod yield (2.2 Mg×ha–1) were produced by fall-0 N+abruzzi rye; spring-strip till+0 N. Minimum aboveground biomass (15.6 g/plant), fresh-market pod yield (2.6 Mg×ha–1) and dry pod yield (0.9 Mg×ha–1) were produced by fall-0 N+ abruzzi rye; spring-conventional till+0 N treatment. Spring-strip till at 0 N produced fresh-market pod yield, dry pod yield, and plant biomass similar to spring-strip till at 30 kg×ha–1 N. Results suggest strip-till provided adequate tilth and nitrogen fertilizer was not needed for producing southernpea in middle Georgia.

Development of an Innovative Space Boom

This paper presents the development of a new type of ultra-lightweight space boom, called the Self-deployable Spring Strip Boom or simply the S3 Boom. It describes the fundamental design concept and several variations of design configurations. Test results of proof-of-concept models are discussed and compared with results obtained by analytical simulations.

The influence of Bauschinger effect on overstrained spring strip

A theoretical Bauschinger chart has been constructed, the data being based on experimental results. This chart is used to predict the resisting moment of the strip whilst determining the residual-stress distribution using a layer-removal technique.