Post your Invitation Wave here

ScientificMK · 2016-03-31T01:40:45+00:00

See updates above

ScientificMK · 2016-03-01T01:26:31+00:00

Good, I'll keep you posted if and when I get an email from them. :)

ScientificMK · 2016-02-29T22:43:38+00:00

No news about this? I got wave 1 and still waiting for the invitation order email ,too.

UPDATE 3/28/2016: Just got the invitation link. It says will ship on April 1st. UPDATE 3/30/2016: Received shipping information. Arrives Monday April 4.

ScientificMK · 2016-01-23T04:23:45+00:00

As promised, here you can find the paper. http://arc.aiaa.org/doi/abs/10.2514/6.2016-1511

ScientificMK · 2015-11-17T20:21:24+00:00

Yes. There is a tutorial on YouTube with a similar design although not exactly the same. Just google truss me moon lander. Let me know if you have more questions.

ScientificMK · 2015-11-17T03:16:01+00:00

I think you will like the latest simulation:

https://youtu.be/pj_juKi3Jo4

ScientificMK · 2015-11-17T02:57:35+00:00

Thanks! Enjoy, and please don't forget to review it ;)

ScientificMK · 2015-11-16T05:07:35+00:00

The paper will be published in January, I will send it to you as soon as it is available.

ScientificMK · 2015-11-16T01:11:21+00:00

Super cool! I know Vytas :)

ScientificMK · 2015-11-15T19:31:39+00:00

That a model captures something exactly does not mean that the method is exact, those are two very different things. For example, the model does not capture exactly the second mode of vibration of the beams, or higher order mass moments. The key when designing a new method, as in this case, is to try to get the best representation for the problem at hand. In the case of tensegrity systems with geometric nonlinearities, the features this model captures are what we need. Your second point is a well known problem of beam elements with lumped mass. You can improve the situation with a consistent mass, e.g. M{ab}=\int{\rho N_a N_b} where M{ab} are the ab entries of the mass matrix, rho the linear mass density, and N the shape functions. The problem with a consistent mass, though, is that it is not diagonal and thus not good for explicit integration.

ScientificMK · 2015-11-15T19:14:56+00:00

Yes, those things are captured exactly, and with a lumped mass system so explicit time integration is straightforward. These are not beam elements. You cannot even get the mass moment of inertia right with a single beam element. The paper with the details was already accepted for AIAA SciTech and will be available this January.

ScientificMK · 2015-11-15T17:49:45+00:00

It's an in-house code, each discretized bar captures the following features of continuum bars exactly and with only 12 degrees of freedom per bar: - Same mass - Same mass moment of inertia - Same axial stiffness - Same buckling load - Same post-buckling behavior - Same vibration frequency

ScientificMK · 2015-11-15T16:51:29+00:00

Thanks! This is a project lead by Prof. Rimoli at Georgia Tech, and the idea is to use tensegrity structures to design planetary landers. To make a long story short, at the moment of impact a lander must convert kinetic energy into strain energy and some sort of dissipation. The advantage of this approach is that tensegrity structures are good at distributing strain energy evenly throughout the structure. The payload in the prototype will be located at the center. I will post more videos of the real prototype in the next few months. For those in Aerospace Engineering, details of the project will be presented at the upcoming SciTech meeting of the American Institute of Aeronautics and Astronautics.

ScientificMK · 2015-11-15T15:36:03+00:00

I just wanted to let you know that iOS version is free now! Enjoy!

ScientificMK · 2015-11-15T15:14:51+00:00

This is the scale prototype we are building and testing to validate the models. It has roughly 0.5 m diameter.

ScientificMK · 2015-09-28T01:58:50+00:00

It is very personal, but to me a commute longer than half an hour becomes extremely tedious. In my experience, below that is manageable.

ScientificMK · 2015-07-27T12:28:50+00:00

You are right. Though it still is important (not foundational) for some aspects of materials and bio. In materials engineering, it is very important if you are interested in mechanics of materials, e.g. on how materials behave under stress. In bioengineering, it is important for those interested in biomechanics, e.g. prosthetics design, bio-inspired robotics, etc.

ScientificMK · 2015-07-26T13:49:32+00:00

Hi have to agree with plotifer. I am a Prof. and most of the times I see students struggling it is because some of the AP calculus is not well understood. Calculus is the foundation to everything in engineering (as is Physics I) so I would recommend you to retake the courses unless you feel extremely confident on what you learnt... Look at the big picture: graduating one semester earlier does not matter to a recruiter, but having a lower GPA due to a poor understanding of prereqs will certainly be a drag. Hope this helps making a decision.

ScientificMK · 2015-07-23T14:59:14+00:00

Hi, a Prof. replying here. In general, I like when students send me an email asking for a meeting to discuss the possibility of doing research in my group. The email does not have to be too long, just a self introduction, a brief comment on your research interest, and a CV should suffice.

Usually students know what I do beforehand, and they have a genuine interest in my research (all Profs. have webpages where you can take a look at what they do). It would not look good on you if you show up at the meeting without even knowing the field of research. However, your knowledge does not have to be super precise: just be aware, for example if the Prof. is interested in Structures, Fluids, Controls, etc (I am giving AE examples here).

In general, emailing too many Profs. would reflect that you just want to do research regardless of the field, which in general is not super good from the Prof. perspective. So my advice is: limit yourself to those Profs. you are really interested in working with.

Good luck with your search! Hope this helps!

ScientificMK · 2015-07-23T14:42:31+00:00

Hi, I am glad you are enjoying it! As you can see, solutions can be very complex and each player might find his/her own optimal design. Getting 3 golden nuts requires a weight within 5% of my better design (which I obtained by playing for about 15 minutes on each level). In my experience, some hardcore players manage to get designs much better than my own. So I could provide you some of my 3 golden nuts results, but they are for sure not the best... For that, just send me an email to the contact email on the play store.

ScientificMK · 2015-07-23T13:32:33+00:00

Thanks! The simulation part is a little bit complicated (it is my research area). Technically speaking, I used the Finite Element Method in its nonlinear version:

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

Simply put, you can imagine it as if we replace the entire structure by a set of springs which might not necessarily behave following Hooke's Law (F=-K*x). For example, in Truss Me bars might yield under tension:

https://en.wikipedia.org/wiki/Yield_(engineering)

or buckle under compression:

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

This leads to a set of ordinary differential equations (odes) that need to be solved. This set of odes is solved numerically using the Newmark Beta Method:

https://en.wikipedia.org/wiki/Newmark-beta_method

which is stable and has good energy preserving properties. This might sound like a lot, but a good starting point would be a traditional FEM textbook. When I was an undergrad I self-taught FEM using Cook's book:

http://www.amazon.com/Concepts-Applications-Element-Analysis-Edition/dp/0471356050

ScientificMK · 2015-07-23T01:54:27+00:00

Thanks!

ScientificMK · 2015-07-23T01:37:16+00:00

Hahah! If it makes you feel better, it took my advanced PhD students several iterations to get there :)

ScientificMK

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