A 15-story (120-foot tall) Artemis truss tower will be assembled on the moon using autonomous spider...

 

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A 15-story (120-foot tall) Artemis truss tower will be assembled on the moon using autonomous spider robots and 8-foot long members. To keep the tower stable during moonquakes, 130 - foot long Kevlar guy wires run from the tower top and are anchored to the lunar surface. The room temperature (70 oF) tension properties for the Kevlar include the yield strength of (204, 223 lb/in2) and the ultimate strength of (207,062 lb/in2). At the moon's southern pole, the outside temperature is expected to be (-400 oF) so that the Kevlar fiber tension strength properties are reduced by 15 % (i.e. knockdown factor 0.85). NASA has decided to require the following safety factors (SFy = 1.6, SFu = 2.0) and a ( +0.16) margin of safety for this unmanned tower and guy wires because it is difficult to quantify the severe lunar (dust) environment and the spider robot assembly performance. During normal operation, the static pre-tension load in the guy wire is equal to 281 lb, but during strong moonquakes, the tension loads in the guy wires will increase by a factor of 4.7. What is the required minimum cross-section Kevlar guy diameter to ensure a safe design? (Units: inch) = A 15-story (120-foot tall) Artemis truss tower will be assembled on the moon using autonomous spider robots and 8-foot long members. To keep the tower stable during moonquakes, 130 - foot long Kevlar guy wires run from the tower top and are anchored to the lunar surface. The room temperature (70 oF) tension properties for the Kevlar include the yield strength of (204, 223 lb/in2) and the ultimate strength of (207,062 lb/in2). At the moon's southern pole, the outside temperature is expected to be (-400 oF) so that the Kevlar fiber tension strength properties are reduced by 15 % (i.e. knockdown factor 0.85). NASA has decided to require the following safety factors (SFy = 1.6, SFu = 2.0) and a ( +0.16) margin of safety for this unmanned tower and guy wires because it is difficult to quantify the severe lunar (dust) environment and the spider robot assembly performance. During normal operation, the static pre-tension load in the guy wire is equal to 281 lb, but during strong moonquakes, the tension loads in the guy wires will increase by a factor of 4.7. What is the required minimum cross-section Kevlar guy diameter to ensure a safe design? (Units: inch) =

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Determining the Minimum CrossSection Kevlar Guy Diameter Heres how to calculate the minimum crosssec... View the full answer