The present paper investigates the collapse process of pipe-framed greenhouses under static wind loading based on a fi nite element analysis in order to establish more reasonable wind resistant design of these structures. The wind direction is limited to that normal to the ridge. In the analyses, both geometric and material non-linearity are taken into account. The fl ow-structural interaction is also considered, because the wind-induced deformation of the structure affects the external pressure coeffi cient distribution on it signifi cantly. Both 2-D and 3-D analyses are carried out. The effects of 3-D pressure distribution and reinforcement by adding members on the collapse process are made clear. The result on the collapse process is consistent with the practical damage caused by strong winds such as typhoons. The effects of various reinforcements made on the frame are discussed based on the similar analyses up to the allowable deformation limit specifi ed in the current design guideline. The results show the most effective reinforcement from the viewpoint of wind resistant design.

View full abstract

Some rice farmers have recently started to grow and harvest corn grain for feed. For rice farmers who intend to grow corn under conditions given little information of postharvest processes of corn in Japan, corn grain drying tests were conducted. We also checked moisture meters that the farmers can readily purchase. Corn grain drying tests were conducted using a conventional circulation dryer designed for rice, wheat, barley, and soy beans. The soybean moisture meter of the dryer can accommodate the corn grain physically. However, because the anti-wrinkling system in soybean mode prevents drying with heat, wheat-mode drying is more practical with a soybean moisture meter dismounted. The drying speed was found to be higher at higher drying temperatures. It was 1-2 %/h with wheat mode. Energy for water removal was 5.5-6.0 MJ/kg, which agrees with previously reported results of the relevant literature. Moisture meters were compared with the oven method, which uses 135°C for 10 g grain during 24 h. Two models of moisture meters for corn based on electrostatic capacity were examined: one domestic and one imported. Both showed good moisture content measuring results. Results for the domestic moisture meter showed less fl uctuation than the imported one. Moisture meters of two types for soybean were examined: one based on electrostatic capacity and another based on electric conductivity between a pair of kernel-crushing wheels. The latter is a part of the grain dryer for soybean drying. Because both were designed for soybeans, the indicated values differed from the moisture contents. The values must be converted to corn moisture contents with the regression equation between the oven method and the examined methods. The moisture meter based on electric conductivity showed less fl uctuation than the other based on the electrostatic capacity.

View full abstract