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Fatigue life Part 2, What I learned and another question : )(4 posts)

Fatigue life Part 2, What I learned and another question : )stinkfoot247
May 5, 2003 8:39 AM
In response to my post below on Fatigue life. I've got an aluminum frame. I'm going get stabbed in the chest by my TT cuz my frame has a low modulus. Yes, I agree that I never hear of SFDS(sudden frame death syndrome). That's why I asked about fatigue lifes significance. If I registered everything right, Fatigue life is caused by applying force over and over again. ??This produces tiny cracks which some day result in a TT in your chest and BB 50ft behind you. Here's the question: Does it matter if you, lets say smash your face into your TT 5 times, stop, next day smash your face into your TT 5 times, and repeat cycle or if you smashed your face 10 times a day. which has a bigger impact smashing face 20 times in 4 days or smashing face 20 times in 2 days.haha.
Micro-vibration=road buzz=cyclical fatigue=death by Al. nmSpunout
May 5, 2003 9:28 AM
Here's (hopefully) a simple explanationKerry
May 5, 2003 5:01 PM
Each stress cycle on Al contributes to ultimate failure, regardless of the level of stress. With Ti and steel, if you stay below the fatigue limit, they are not going to fail. It is the number of cycles and the intensity of the cycles, not whether it is 100 times one day or 10 times per day over 10 days. We're talking about the normal impacts of potholes, pavement cracks, etc. not crashes. Not sure what you mean by "smash your face into your TT" - it sounds like you are crashing? All that said, until you get to superlight frames and heavier riders, the fatigue life of the metal likely will have no practical impact on the life of your frame.
smashing your face into TT exlpanationstinkfoot247
May 5, 2003 5:48 PM
TT= top tube. Smashing your face into TT would be: Take a man who is angry because he purchased 172 instant lottery tickets. He never won a dime. He is angry and takes it out on the the top tube of his bicycle by smashing his face into it. To smash your face into your TT follow these simple procedures:
1. stand with feet shoulders width apart holding bicycle with arms making a 60 degree angle.
2. you are standing perpendicular to your bike.
3. now using your stomache muscules thrust your face into the top tube of your bicycle while cursing the world.
4. remove any loose teeth and lick your wounds.
5. repeat if nessecary.