I'm trying to determine the force required to break a piece of cord.
Setup: A fixed boom at the top, with tensionless attachment suspends a piece of cord of the type being tested. A weight of 8 pounds is secured to the lower end, and the weight dropped from successively greater height until the cord breaks. A new piece of cord is used for each drop to avoid cumulative damage to the sample being tested.
Now, my (probably erroneous) thinking says that the velocity of the weight (derived from v=at) in feet/second * mass of the weight (8 pounds) yields a force in foot/pounds.
Example: The 8 pound weight does not break the cord when dropped 18". A drop of 22" breaks the cord. My method suggests a breaking strength of about 80 foot/pounds, which was significantly higher than I expected. The rated strength of the line is 22 lbs, so my numbers are not out of the ballpark, but are perhaps way out in left field... May be apples and oranges as well, i.e. dynamic vs static loads.
This is all about engineering parachute shroud lines, and managing the dynamic loads of deacceleration at opening. TIA for setting me straight on the proper method of figuring the forces involved. (yeah, yeah, I know... the Knacke manual)
Kevin OClassen