Recently, I wrote a blog post about computing section properties. I discussed using Green’s Theorem to compute the area integrals needed to compute section properties (area, centroid and moment of inertia) and I made the guess that this is how commercial software probably computes the section properties of arbitrary …
Lately I was thinking about computing section properties programatically. Of course, any engineering undergrad can compute the area and moment of inertia of a section comprising rectangles and other simple shapes — for example, a tee-section or an I-beam section. There is software out there that computes section properties of arbitrary …
I’ve been thinking about how to explain an A- or B-Basis value to people without much statistical knowledge. These are the names used in aircraft certification for the lower tolerance bounds on material strength. The definition used for transport category aircraft is given in 14 CFR 25.613 (the …
There are a lot of misconceptions about bonded joints. One of the misconceptions that I’ve seen most often is that people think that the average shear stress in a lap joint is predictive of the strength. This same misconception is usually phrased as either:
I’ve made a few violin bows and a couple cello bows. I’m very much a novice bow maker, but I’m learning. As I’m an engineer, I’m naturally trying to apply engineering principles to bow making, which isn’t necessarily easy since violin bows are actually …
Up until recently, I hadn’t really thought about the way that numerical integration was performed.
Sure, I knew about some techniques like using the trapezoid rule to perform numerical integration,
and without thinking about it too much, I had just assumed that the integration routines like
R’s integrate …
I’m going to release a new version of cmstatr
soon. This new version includes, amongst other things, a new vignette.
In R packages, a vignette is a type of long-form documentation.
This particular vignette includes a simulation study that helps to
demonstrate the validity of a particular statistical method …
Calculating tolerance limits — such as A-Basis and B-Basis is an important part of developing and certifying composite structure for aircraft. When the data doesn’t fit a convenient parametric distribution like a Normal or Weibull distribution, one often resorts to non-parametric methods. Several non-parametric methods exist for determining tolerance limits …
Earlier, I wrote a post about using a likelihood-based approach to calculating Basis values. In that post, I hinted that likelihood-based approaches can be useful when dealing with censored data.
First of all, what does censoring mean? It means that the value reported is either artificially high or artificially low …
All materials have some variability in their strength: some pieces of a given material are stronger than others. The design standards for civil aircraft mandate that one must account for this material variability. This is done by setting appropriate material allowables such that either \(90\%\) or \(99\%\) of the material …
From what I’ve seen, a lot of the statistical analysis of data from composite material data is done in MS Excel. There are a number of very good tools for doing this analysis in MS Excel: ASAP, HYTEQ, STAT-17, and more recently, CMH17-STATS. I expect that the …
Edit (26-May-2022): This post is largely obsolete, now that GitHub is able to render math in Markdown documents, including issues. I’m keeping this post up for historical reasons, but I’d now recommend that you now use GitHub Issues directly and include mathematica notation as needed.
I’m currently …
The main benefit of using Notebooks (R Notebooks or Jupyter Notebooks) is that the document is reproducible: the reader knows exactly how the results of the analysis were obtained. I wrote about the use of Notebooks in an earlier post.
Most organizations have a certain report format: a certain cover …
I’ve been working on a Python package to analyze adhesively bonded joints recently. This package will be used to analyze adhesive joints in certain aircraft structure and will be used to substantiate the design of structural repairs, amongst other uses. Because of this, the output of this package needs …
Reproducibility in engineering work doesn’t seem to get the attention that it deserves. I can’t count the number of times that I’ve read an old engineering report in search of a particular result, only to find that the calculation that lead to that result is only barely …
For the last couple of years, we’ve been using the statistical programming language R when we do statistical analysis or data visualizations at work. We typically deal with small data — most of the time, our data sets are high-tens or low-hundreds of rows of data.
A lot of the …
Welcome to kloppenborg.ca
I plan to use this website as a blog where I discuss topics related to engineering, technology and whatever else I’m thinking about at the time.
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