## { Author Archives }admin

### Calculating changes in principal stress directions

We recently had a requirement to determine the change in direction of the principal stress between two load cases. Specifically, we were modeling the grout between a pile and pile sleeve in a removal operation. The sequence of removal was: Remove structure above waterline. This reduces the stress but probably doesn't change the principal stress [...]

### Plastic LED Heat Sink

Luminaires with a high density of LEDs will provide a lot of light with high lumens per Watt but about half of the Watts will be dissipated as heat. Engineering a fixture that provides a heat path comprised of high thermal conductivity materials such as aluminum is an easy but not necessarily cost effective solution. [...]

### How to create attractive polar plots using matplotlib

A client requested help creating attractive polar plots. I assumed that we could use matplotlib to help them. The code below produced nice plots. import matplotlib.pyplot as P import matplotlib from matplotlib import rc rc('text', usetex=True) rc('font', family='serif') P.clf() sp = P.subplot(1, 1, 1, projection='polar') sp.set_theta_zero_location('S') sp.set_theta_direction(-1) plot1=P.plot(measured_angle, measured_data, color='b') p1 = P.Rectangle((0, 0), 1, [...]

### Elastic modulus of grout from compressive strength

A recent project involved the estimation of the elastic modulus of grout from the compressive strength. When performing an analysis on a to-be-built offshore structure with grouted pile-in-sleeves, the compressive and tensile strength, elastic modulus, and Poisson ratio can be looked up on the datasheet or supplied by the grout vendor. But this project involves [...]

### Installing Abaqus CAE on Ubuntu 12.04

$sudo aptitude install csh alien$sudo mkdir /opt/abaqus $sudo /media/Abaqus6111/setup -nosystemchecks # Fix compiz bug$alias abaqus='XLIB_SKIP_ARGB_VISUALS=1 abaqus' # Install some dependencies $sudo apt-get install libjpeg62$sudo aptitude install libstdc++5 The compiz bug fix was found here Update: Although there is always a graphical artifact on my screen, CAE crashes less often than on Windows.

### Parametric Abaqus model generation with CAE

Building parametric models in Abaqus CAE may seem trivial at first blush, simply set CAE to output ids instead of masks and insert a little python code where needed. After spending many hours developing the application, you deploy and all the engineers are happy. Until you upgrade Abaqus to the next release. I have found [...]

### Offshore Wind Generator Foundations

Jack-up installing turbine on mono-pile foundation Offshore wind turbine foundations are designed to owner and jurisdictional specified codes. Typically, North Sea installations would follow Offshore Standard DNV-OS-J101, Design Of Offshore Wind Turbine Structures. Grouted connections are typically used to connect the pile to the sleeve in mono-pile and other constructions. Section 9 of DNV-OS-J101 covers the design requirements for grouted [...]

### We have moved!

After moving our domain registrar, our old hosting service inexplicably deleted our site. Oh well. We are now self-hosting on Amazon's EC2.