"Richard Harrison" bravely wrote to "All" (14 Jul 05 12:04:53)
--- on the heady topic of " AD5TH Tower - Storm Damage Photos"

RH From: (Richard Harrison)
RH Xref: aeinews rec.radio.amateur.antenna:34153

RH Some metals such as steel and titanium have lower stress limits below
RH which they are mostlly im,mune to failure from repeated flexing. Other
RH metals such as aluminum and its alloys have no such immunity and
RH eventually fail under repeated flexing. In these, designs are kept
RH below the fatigue threshold for the number of stress cycles expected
RH within their lives. Or, a lifetime is specified and replacement is
RH required. Another technique is non-destructive testing to find cracks
RH and the piece is retired for cause.


How can one estimate stress cycles from a wind load?

A*s*i*m*o*v

.... All the tea in china: 356,000 metric tons.