Titanium Chain Plates and Mast Fittings

[Stumble]

Originally Posted by Wind River

Does anyone know a good source for titanium fasteners?

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Do you need one or a thousand?

Allied Titanium has some retain sales thru Amazon, or you can contact them directly for anything not there (the MOQ is pretty low). Fastenal, and Fasteners Inc also carry some, as does McMaster Carr.

[Wind River]

Chain plates would require about 50, 1/2" - 13 with nuts. Also I would need 1/2 solid bar to make some extra long bolts, about 5 feet should be enough .
Thanks, I will check your sources. I found a several doing goggle searches but only a couple that list any pricing and they were very different from one another. .

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[Stumble]

Call the sales department at allied with a complete parts list. In the past they have made some custom bolt lengths, I would just ask them, or see if they have threaded rod.

[F10]

Originally Posted by estarzinger

I had quite a bit of experience with Ti, when I did 6 sigma at ge aircraft engines.

I agree it has nice properties.

But it creates engineering challenges . . . . And high level yachting has struggles with those challenges. Just for example . . . . There were a whole bunch of tI ram failures in both Volvo and imoca, and a snapped off tI keel after only 10 days use (Marc Guillemot's ) keel that simply broke off. Most "forming" processes are difficult - welds are not good under load.

Frankly in aerospace, composites have replaced quite a bit of the Ti

I looked into the failures you bring up. From my limited internet research it seems the failures were due to design (and maybe also fabrication) errors. It seems that the failures were due to not designing the part to the full stress the part would see in service. There were also some keel failures on these boat and the keels were fabricated carbon steel. So it looks like Ti is not the problem- the problem is with adequate design. Looks like there was also some push to have these type of race boats have forged steel keels- super strong and most fabrication errors might be eliminated.

The problem is that what works for these once around high tech race boats and what will work for a cruiser or day sailor may not be the same. After all a well designed race boat will come in first, and then have everything break and sink just after crossing the finish line.

I see companies do sell Ti chain plates and other rigging gear. What I am looking for is any failures or things to look out for while using this material.

[Cheechako]

Well.... failure is always part of design. Design specifies material also. Many designs use a safety factor of 3. That is... if your allowable stress is say 30,000 psi, then you build for 90,000 psi.
Engineering is an imperfect science... why? because not all conditions or stresses are predictable. Remember the Americas Cup boat that broke in half and sank in light airs in San Diego? There were millions spent on engineering on that boat.

[F10]

Originally Posted by Cheechako

Well.... failure is always part of design. Design specifies material also. Many designs use a safety factor of 3. That is... if your allowable stress is say 30,000 psi, then you build for 90,000 psi.
Engineering is an imperfect science... why? because not all conditions or stresses are predictable. Remember the Americas Cup boat that broke in half and sank in light airs in San Diego? There were millions spent on engineering on that boat.

from Wikipedia:

https://en.wikipedia.org/wiki/Factor_of_safety

Choosing design factors[edit]

Appropriate design factors are based on several considerations, such as the accuracy of predictions on the imposed loads, strength, wear estimates, and the environmental effects to which the product will be exposed in service; the consequences of engineering failure; and the cost of over-engineering the component to achieve that factor of safety. For example, components whose failure could result in substantial financial loss, serious injury, or death may use a safety factor of four or higher (often ten). Non-critical components generally might have a design factor of two. Risk analysis, failure mode and effects analysis, and other tools are commonly used. Design factors for specific applications are often mandated by law, policy, or industry standards.
Buildings commonly use a factor of safety of 2.0 for each structural member. The value for buildings is relatively low because the loads are well understood and most structures are redundant. Pressure vessels use 3.5 to 4.0, automobiles use 3.0, and aircraft and spacecraft use 1.2 to 3.0 depending on the application and materials. Ductile, metallic materials tend to use the lower value while brittle materials use the higher values. The field of aerospace engineering uses generally lower design factors because the costs associated with structural weight are high (i.e. an aircraft with an overall safety factor of 5 would probably be too heavy to get off the ground). This low design factor is why aerospace parts and materials are subject to very stringent quality control and strict preventative maintenance schedules to help ensure reliability. A usually applied Safety Factor is 1.5, but for pressurized fuselage it is 2.0, and for main landing gear structures it is often 1.25.[11]
In some cases it is impractical or impossible for a part to meet the "standard" design factor. The penalties (mass or otherwise) for meeting the requirement would prevent the system from being viable (such as in the case of aircraft or spacecraft). In these cases, it is sometimes determined to allow a component to meet a lower than normal safety factor, often referred to as "waiving" the requirement. Doing this often brings with it extra detailed analysis or quality control verifications to assure the part will perform as desired, as it will be loaded closer to its limits.
For loading that is cyclical, repetitive, or fluctuating, it is important to consider the possibility of metal fatigue when choosing factor of safety. A cyclic load well below a material's yield strength can cause failure if it is repeated through enough cycles.

[F10]

Originally Posted by Cheechako

Well.... failure is always part of design. Design specifies material also. Many designs use a safety factor of 3. That is... if your allowable stress is say 30,000 psi, then you build for 90,000 psi.
Engineering is an imperfect science... why? because not all conditions or stresses are predictable. Remember the Americas Cup boat that broke in half and sank in light airs in San Diego? There were millions spent on engineering on that boat.

Preaching to the choir. They just over paid for the wrong engineers. BTW, I am a licensed mechanical engineer.

[Cheechako]

Your post #19 confuses me if you are an engineer... :>) It's a real world out there. Yep, worked Aerospace engineering for over 30 years.