Since we are basically a R&D startup trying to develop a new technology, we have limited $$ and test time (and expertise). So we have identified some key components based on past failures and tested those. But our device is complex and there are many more components/assemblies that we can't test...
Not making things up, just not communicating the problem well (taking a component designed for controlled conditions and using it in a marine environment where you can get 'Perfect Storm' conditions).
"It uses off the shelf components in ways that differ from typical usage": for example, we are using parts not designed for a marine environment, one aspect of which is that waves produce variable rather than cyclic loading (i.e. amplitude and period are not constant). We just have an atypical...
We are developing a new product. It uses off the shelf components in ways that differ from typical usage, so it is hard to get accurate information about component life. Because the design is still being refined, we will not be building and testing multiples for a while. Is this too early in the...
I am looking for a global map that shows the areas of world which have active offshore oil & gas operations, and that also indicates how much activity is going on. It just needs to communicate where oil & gas activities are taking place in the world ocean.
If you could suggest a link or source...
I found the article 'Joint modelling of wave spectral parameters for extreme sea states' by P. Jonathan, J. Flynn, and K. Ewans, which discusses how to estimate extreme Hs and associated Tp. My method above should not be used. I will be trying to implement this using the tools in the WAFO...
I know how to estimate the 100-year wave height from a time series of wave measurements, but not how to estimate the wave period associated with the 100-year height. Let's say based on a 20-year time series of sea surface elevation measurements, the 100-year height is estimated to be Hs=15m, but...
I am trying to calculate the daily C02 emissions from a ship following this EPA report. Table 5-1 lists the C02 emission rate to be 44.1/(Fractional Load) + 648.6 in units of g/(kW-hr). Here are my questions,
1) What does the kW in the units represent? The ship engine's power output? My...
This question concerns a property of the directional wave spectrum, namely the one-sided directional width (sigma), which describes the amount of directional spreading of waves. Sigma is like a standard deviation of the wave direction. There are other ways to measure directional spread but sigma...
Any thoughts on the fact that my team members will be smarter and more technically skilled in many areas than myself?
I suppose I ask them for the big picture so I can make project decisions, and let them own the execution.
I am about to transition from being an engineer to managing a small group of engineers. I would love recommendations for books, professional organizations, or other resources on managing an engineering team. I really liked this article. Presently I plan out and manage my own efforts, but soon...
Can someone point me to a standard for mooring design that ensures that marine mammals do not become entangled? I am thinking specifically of a bridle or other "closed loop" in a mooring system, and want to know what loop diameter would be large enough that marine mammals cannot become entangled...
You are exactly right. I have been working through 'An introduction to statistical modeling of extreme values' by Stuart Coles - highly recommended. On p. 57, 'estimates and their measures of precision (i.e. the confidence interval that I was looking at) are based on an assumption that the model...
What I want is some metric indicating the fit is poor, and that metric is *not* the confidence bounds, I think. Instead I think the confidence bound is a measure of how noisy the fitted data is. So perhaps a better measure of fit goodness is the RMS value of the difference between the fitted and...
I am using the helpful package WAFO to estimate a survival load for a structure, but I am having trouble interpreting the results.
Background:I have a measured time series of the load, and I identify peak values using the "peaks over threshold" method. The identified peaks are then fit to an...
In thread311-297005, I asked about the standard use of a 3-hour return period to determine the maximum load occurring in a 100-year storm (e.g. Hs=15m). The underlying assumption is that when a 100-year storm occurs, you want your structure to survive the worst load expected to occur if the...
I found a nice overview of cumulative damage theory at the link below.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCAQFjAA&url=http%3A%2F%2Fwww.dtic.mil%2Fcgi-bin%2FGetTRDoc%3FAD%3DAD0758414&ei=5nZPUMbjO8qmrAeX64DAAQ&usg=AFQjCNGt3izvQ472agqe8bAbtnhnycYcFQ
...doubling the load reduces the life to 1/8, and the wear is applied over the total distance the bearing moves, which leads to units of [Newtons^3]*[Meters]. I will try to get better oriented and repost once I have the big picture. But I still don't "like" these units since I can't relate them...
