Den ons, 11 oktober 2006 12:43 skrev Peter Markusson:
Oj, det var värre än jag trodde! Skönt att det ordnade upp sig så snabbt och generöst. Ska bli intressant att se om Hase lyckas få fram någon orsak till haveriet.
Jag postar svaret från Jeff Burkey på Aktiv Hjelpemidler utanför Oslo som har levererat cyckeln. Det är mycket uppklarande:
Hi,
If Hase has agreed to replace the broken part you should leave it at that, do not mess with a good thing.
Please remember it is only a Bike, not a space vehicle.
If you really want a technical explanation can get one for you, however I truly doubt you would be able to understand the entire report.
In Short ...... after pushing the bike over many miles it broke.
From what I can see, it is more likely that there was a flaw in the material
long before it was welded into a bike, this is the kinda stuff you can not predict. Titanium is very light and strong, but also very brittle and has a tendency to creep under extreme loading or temperature or both. If you look at the crack itself it appears the the metal was torn or ripped, this is a indication of prolonged vibration with stress or Flexure .... moving back and fourth. This back and fourth movement can be in the Micro Millimeters and still destroy metal.
The large part that is missing in the photo, if you notice the top of the hole is sorta or more round, this is a smooth crack or fault line, the bottom has one sharp corner where 2 crack lines meet. This is the most likely point where the crack started. Titanium is a composite of different materials, and at the compound level looks like a stack of billiard balls. If there is a problem in the material, like some type of inclusion (1 ball missing), or (balls out of the right place), and then you strike the stack with a Que or put stress on the stack .... the entire stack will begin to fall apart and move in different directions, this is known as a crack. Over a long period of time you get what happened in the photo.
I did not have a view of the bottom, but typical failure in metal assoicated with fabrication, or assembly, as someting like Weld joint failure ... or cracking in the weld joint, cracking in or arround the festing locations, ... stuff like that. The reason for this is that when you weld 2 parts together the material at the joint physically different, in general it is much harder and more brittel, a bit more like glass than metal. This is because of the extreme heating and cooling during the welding process. The area around the weld is called the Heat Effected Zone. Anywhere you have a weld, you have the possibilities to have trouble in that zone, sorry it is very difficult to do much about these issues. But again, this is not what is shown it the picture.
Anyhow, I could go on and on, but for the moment I am somewhat busy getting stuff ready for winter. So below is a basic conclusion.
The Last Word ...
1. The Bike did not fail as a result of Design, Manufacturing, Fabrication, Assembly, or infact Riding (usage).
2. The most likely cause of failure is a micro level flaw in the manufacturing of the metal or material, which propagated a crack during normal usage. This crack then Crept (actual technical term) until ultimate failure of the assembly.
Be Happy !!! they are going to fix your bike.
Call me on the work mobil if you need any further Pondering, let me know when you are going to be back in Norway so we can take properly fix your battery box issues.
till later,
jeff