Saturday, December 6, 2014

Fully Scripted Open Source Topology Optimization

Helical Extruder Gear for Printrbot with Optimized Topology

I've used a couple different methods for stringing together open source tools to do topology optimization, but they have all required some interactive user input. Here are some previous posts demonstrating those manual methods:
Those approaches are fine if you've got time to fiddle with interactive software, but I wanted to do some parametric studies, so I need an automated approach that would be scalable to lots and lots of optimizations.

Thursday, November 20, 2014

119 Open Source Aeronautical Engineering Tools

I posted a list of 33 open source aeronautical engineering tools on LinkedIn a couple days ago. One of the comments was a question about how open they all really were so I added a column to the list for the license and any non-free dependencies (i.e. Matlab). I went ahead and made an entry for each of the pieces of software from Ralph Carmichael's PDAS collection, which added 84 public domain pieces of software. In addition, there are 23 with various flavors of GNU, 4 BSD-style, and 3 NASA open source agreement (NOSA) codes. See the whole list below the fold. Please suggest adds/changes/deletes in the comments.

Monday, August 18, 2014

Validation & Verification in Physics of Plasmas

Physics of Plasmas is making a collection of 20 papers on verification and validation available for free download for a limited time.
Theoretical models, both analytical and numerical, are playing an increasingly important role in predicting complex plasma behavior, and providing a scientific understanding of the underlying physical processes.

Since the ability of a theoretical model to predict plasma behavior is a key measure of the model’s accuracy and its ability to advance scientific understanding, it is Physics of Plasmas’ Editorial Policy to encourage the submission of manuscripts whose primary focus is the verification and/or validation of codes and analytical models aimed at predicting plasma behavior.

Saturday, July 19, 2014

FreeFem++ Topology Optimization Scripts

There are lots of open source topology optimization options out there (e.g. 99 line code, ToPy) that I've written about before. One that I haven't posted about yet is a collection of FreeFem++ scripts by Allaire, et al. that illustrate a variety of topology optimization approaches and problems. FreeFem++ is a partial differential equation solver based on the finite element method. FreeFem++problems are defined in scripts that use a high level language. FreeFem++ itself is written in C++.

Tuesday, July 1, 2014

UAVs for Film and Profit

Yesterday's AIAA Daily Launch had a great round-up of some recent UAV news:
  • Wall Street Journal (6/27, Nicas, Subscription Publication) reported on the ongoing fight over U.S. unmanned aircraft rules, which is pitting high-tech entrepreneurs against major aerospace and defense companies.
  • Washington Post (6/28, Whitlock) reported that a majority of U.S. military UAV accidents occur abroad, but “at least 49 large drones have crashed during test or training flights near domestic bases since 2001, according to a yearlong Washington Post investigation.”
  • AP (6/28, Jelinek) reported that the Pentagon announced armed UAVs are “flying over Baghdad to protect U.S. troops that recently arrived to assess Iraq’s deteriorating security.”
  • South Florida Sun Sentinel (6/29, Anthony) reported that Boynton Beach is dropping plans to ban drones in order to boost its “fledgling image as a technological hot spot — a place that welcomes engineers and innovation.”
  • South Bend (IN) Tribune (6/29, Sheckler) reported that as UAVs become cheaper and more available to the public, and their popularity grows among hobbyists and entrepreneurs, “they will increasingly raise questions about how to best regulate them, and how to balance concerns about safety and privacy.”
  • Hollywood Reporter (6/27, Giardina) reported that Hollywood movie studios are interested in using UAVs in filming “because they hold the promise of new creative options, real cost savings and possibly even safer sets.” Federal law prohibits the commercial use of UAVs, so filmmakers choose to shoot in countries with lax UAV laws to get the shots needed for their films.
Most interesting are the petitions of the seven aerial photography companies for exemptions for commercial filming operations. As the FAA press release says, the seven Section 333 Exemption Applications for Commercial Operations of Unmanned Aircraft are available on I think it is interesting that these companies are taking this approach, because in some fillings by Pirker they specifically call out historical use of remote control aircraft for movies and TV (one of four broad categories of commercial use they cite). The applications have 18 "limitations and conditions" under which commercial operations will take place. They also make this interesting claim: "These limitations provide for at least an equivalent or even higher level of safety to operations under the current regulatory structure because the proposed operations represent a safety enhancement to the already safe movie and television filming operations conducted with conventional aircraft."
To drive that point home they show a couple pictures of a manned helicopter filming as it currently occurs.

Sunday, June 29, 2014

3-in Tack Strip Bracket TopOpt

I found a useful bracket on thingiverse for mounting things on a 3-in tack strip. Of course I thought this was a perfect opportunity for a bit of topology optimization. All of the design files and the stl (rendered above) are available on GitHub. The part is also on thingiverse.

Here's a video showing the progress of the optimization:

Rendered with a wave texture in Cycles to give the layered look it would have from an FDM machine, not quite right, but pretty close:

Thursday, June 26, 2014

HiFiLES v0.1 Release

The folks at the Stanford Aerospace Computing Lab have recently released version 0.1 of HiFiLES. "HiFiLES is a high-order Flux Reconstruction solver for the Euler and Navier Stokes equations, capable of simulating high Reynolds number turbulent flows and transonic/supersonic regimes on unstructured grids."

From the release notes:

High-order numerical methods for flow simulations capture complex phenomena like vortices and separation regions using fewer degrees of freedom than their low-order counterparts. The High Fidelity (HiFi) provided by the schemes, combined with turbulence models for small scales and wall interactions, gives rise to a powerful Large Eddy Simulation (LES) software package. HiFiLES is an open-source, high-order, compressible flow solver for unstructured grids built from the ground up to take full advantage of parallel computing architectures. It is specially well-suited for Graphical Processing Unit (GPU) architectures. HiFiLES is written in C++. The code uses the MPI protocol to run on multiple processors, and CUDA to harness GPU performance.

The main reference for the code right now is this V&V paper.[1] The code uses an Energy Stable Flux Reconstruction (ESFR) scheme. Here are a couple papers on that approach.[23].


[1]   L√≥pez-Morales, M. R., Bull, J., Crabill, J., Economon, T. D., Manosalvas, D., Romero, J., Sheshadri, A., Watkins II, J. E., Williams, D., Palacios, F., et al., “Verification and Validation of HiFiLES: a High-Order LES unstructured solver on multi-GPU platforms,” .
[2]   Vincent, P. E., Castonguay, P., and Jameson, A., “A new class of high-order energy stable flux reconstruction schemes,” Journal of Scientific Computing, Vol. 47, No. 1, 2011, pp. 50–72.
[3]   Castonguay, P., Vincent, P. E., and Jameson, A., “A new class of high-order energy stable flux reconstruction schemes for triangular elements,” Journal of Scientific Computing, Vol. 51, No. 1, 2012, pp. 224–256.

Thursday, June 5, 2014

Emerging and Readily Available Technologies and National Security

Here's the description of this report from the NAP site:
Emerging and Readily Available Technologies and National Security is a study on the ethical, legal, and societal issues relating to the research on, development of, and use of rapidly changing technologies with low barriers of entry that have potential military application, such as information technologies, synthetic biology, and nanotechnology. The report also considers the ethical issues associated with robotics and autonomous systems, prosthetics and human enhancement, and cyber weapons. These technologies are characterized by readily available knowledge access, technological advancements that can take place in months instead of years, the blurring of lines between basic research and applied research, and a high uncertainty about how the future trajectories of these technologies will evolve and what applications will be possible.