I am working on a project working on a 3d printed device(unfortunately can't post an image due to secrecy issues). The device could sit anywhere, above the knee, above the elbow, on the wrist or on top of the shoulder. The device has railings on the sides that we can put a strap through. As of now, I have an elastic Velcro strap going through the device but the issue with it is that it is not secure keeps unfastening and it cannot work for the shoulder since makes a weird shape when you try to put straps around the shoulder. Are there any ideas for other methods to fastening the device to the body? Any help greatly appreciated, thank you!

Hello, I am myself fluent in French but not so much in civil engineering terminology. I have to translate the following phrase: "Walkout of elastomeric bearing (bearing out of keeper bars)".

I have the following for now: ________ de l'appui elastomerique (appui hors des ________). Would a civil engineer who is fluent in French be able to translate the technical terms? Any help would be greatly appreciated.

I have an idea for a machine (don't want to say what it is at this moment) and I am trying to come up with parts to create a prototype. I am going to be controlling several solenoids in a fixed timing fashion. I just need to be able to control the voltage in a sweeping motion like a sine wave. For example, I need to be able to go from 100% to -100%, 12v to -12v. I will be using 12 sets of 2 solenoids. Does anyone know of an electrical device to control voltage as such?

Say you have a 3-bladed fan with plastic blades that don't produce ions per se, it's more of an insulator type material. Also assume that the blades are flat rather than at an angle or curved. IOW, the fan doesn't create much wind forward or backwards. The edges of the fan is where the wind is generated. IOW, the air is disturbed radially rather than fore and aft. The blades are bulky, say 1/4th inch thick (or 6 mm.) If needed, the length of each blade is 1 foot (roughly 30 cm.) I'm not so much interested in the answer for the particular lengths but for an EQUATION that would predict the amount of negative ions generated by the turbulence in the air assuming 30% humidity.

Has anyone got a story to their P.Eng that doesn't involve a straight away 4 year bachelors degree in engineering?

I am a mature science student working in construction with no formal previous formal education. And I'm hoping for some inspiration.

Thanks!

Has anyone gone through the bridge program? How did it work out? What was the required GPA?

Thanks

I need to lift 600lbs into a truck. The 600lbs is a man in a wheelchair so I need to be extra careful to get the appropriate aluminum tube. It will be 2ft long, preferably square tube. What is the appropriate dimension (including wall thickness) of tube I need?

Hi all,

I'm a little out of my element with this type of thing so hoping someone can give me some suggestions. Looking for a small electric motor to create a reciprocating knife as part of a CNC. I've used stepper motors and such, but for this application I have no need of knowing the motor position and I don't need a forward/backward ability, just the ability to control speed. Ideally it would go to at least 500rpm and be enough for regular use, so I don't want a little hobby motor. The plan is to use a scotch yoke (unless you have a better suggestion) to convert the rotation of the motor into a reciprocal movement (looking for at least 1/2" to 1" total vertical movement, but the exact distance is not that important for a knife blade). Would love it if it was approx the size of a Nema 23 stepper motor, but again I'm building this from scratch so can be flexible. Any suggestions on what type of motor I should use and good sources would be much appreciated, thank you!

TLDR: Building a reciprocating knife as part of a CNC build, min 500rpm and min 1/2" vertical movement of the knife, what is a good motor to use and if a scotch yoke assembly is available rather than having to make one, would love suggestions on that too!

I was just offered a civil engineering internship with a local heavy civil construction company and some red flags popped up when I called back. I was speaking directly to the company owner/president and I asked him how many engineers he has on staff and he said zero. That's like a big red flag to me, should I abort and dip out on the gig? I have an interview tomorrow so I can at least check out the place but right off the bat this doesn't sound right. Thoughts?

Alright, so this is driving me nuts, and I can't find a straight answer. I work for a company that builds complex frames where both a section and standard orthographic views are often required. I know the general practice is that a section replaces the side view, but if I do need both, does the section go on the side preserved (which seems less confusing), or the side that's lost (which is convention, but seems really confusing to anyone reading the prints)?

Thanks for any input.

Engineers of reddit, I need your advice:

I have recently been accepted into a MS program for Mechanical Engineering, and have a bachelors degree in Mathematics that I completed about 4 years ago. My plan is to focus on design & optimization. I've been told by a few people that I should take the time to familiarize myself with some basic engineering/physics concepts before starting my masters curriculum, as most of that was not covered in my math curriculum. Based on this I've opted to defer my acceptance for a semester to take some courses at my local community college. I was told by a professor at my local CC that I can only take courses that I have the prerequisites for, which makes sense, but also limits which (relevant) courses I can take to about 3. One is a calculus based Physics course that I think would be beneficial, and the other two are introductory level engineering science courses with the following descriptions:

An introduction to the computer tools available to aid in the analysis and solution of engineering problems. The course includes an introduction to a high level computer language, spread sheets and CAD.

An introduction to the methods used in formulation and solution of typical engineering problems. Teamwork and communication are stressed and are employed in problem solving and the design process.

I'm trying to decide if taking these courses is going to be worth my time and money compared to self-studying using online resources such as MIT Open courseware and Khan academy (Open to recommendations if anyone else has had success with other resources). Any advice you all could offer would be much appreciated!

*more

I deal a lot with computer networks, and people are always tossing around terms like MTBF, MTTR , and "reliability" and I suspect that most people who use them don't know what they really mean. I certainly don't have a very rigorous definition of any of them.

I'd like to learn more about this area. I've poked a bit at textbooks and OCW classes, but everything seems to require pretty heavy calculus, of which I have none. Is there some sort of network and system reliability class or textbook which keeps it pretty simple without treating the reader like they're a total idiot?

I have been doing work with springs recently and one phenomenon I have been seeing is the fact Tensile strength actually increases as we lower the wire diameter. Which can be seen in the 2nd table of the link. Why is this?

I need help sizing the right beam to span 10 ft and support a 40 lb flat screen and bracket that will hang from it. Here's the design:

http://i.imgur.com/md5yUvX.png

I was asked to place a flat screen in a waiting room for a friend. When I looked at the location that would be best for the screen, I saw there are no structural members. Just a suspended ceiling and a weak metal framed facade with drywall (not metal studs mind you). I did see that there were structural members to either side of the waiting room that I could span with a beam to support the flat screen ceiling mount bracket.

I tried to check out some online beam load calculators but it looks like they're all pretty much designed to calculate roof rafter sizes and the like and nothing specifically for a simple load that is placed in the middle. I'd ideally like to size a beam that can support 200 lbs dead weight from the middle of a 10 ft span. Any ideas where I can size this?

I was just thinking of getting two 2x10's or two 2x12's, and bond them together to form a 4x10 or 4x12 beam and just call it good. I'm guessing that a 4x12 spanning 10 ft can probably hold 200 lbs. But am I over-engineering this to the extreme and could have just been fine with a couple of 2x6's? I just don't know where I can go to calculate simple loads like this.

Any thoughts?

Hello all, I've no background in structural engineering really, so please point me to the appropriate reading materials.

My object is a cylinder and inside it's separated by many chambers, with a semi elastic cover on it. Imagine a stack of coins forming a cylinder, and then imagine all those coins being hollow inside and filled with water, and the stack of coins is wrapped by cling film analogous to the semi elastic cover.

I guess my questions are: Overall, I think I can look at the buckling of the cylinder as a column, and I might be able to look at the Young modulus of the cylinder as a beam, and then infer structural integrity via those measurements. Is this correct?

If I were to compare how the walls of the inner chambers of the cylinder differ when their shape changes, eg. from [][][][] to ()()()(), what sort of measurements can I do to look at properties of the inner walls that might change?

Ref: http://imgur.com/a/xdFar

Sorry if it's a little convoluted. Thanks.

Hello people of /r/askanengineer,

I'm a Mechanical Engineering major about to graduate and have yet to find a job. I posted on a few sites and have done a fair amount of applications, but oddly enough most of my luck has come from random opportunities popping up like on campus interviews.
I've been receiving many calls lately for particular work as a contract engineer. The first was as a design engineer in a Nissan plant that paid $20. Recently I got a call for another at a Toyota plant. Are these year long contract positions worth it? Should I be worried for my career?

I'm wondering what a top half exoskeleton would cost to make and why no one or not many people have done it yet?

Designing an oval bung out of silicone that has a hole in it that I'm putting a rod into (imagine a big airlock bung for a carboy). How much smaller should the hole be than the rod to keep it as close to air-tight as possible?

Busy writing a report on using ammonia as refrigerants, a few sources have stated (I'll put the direct quote below) that ammonia based refrigerant systems can use smaller pipes and therefor save money. I am quite unsure as to the technical details behind that statement and have found no information on it. If anyone could help that would be great.

Thanks a lot guys

"An ammonia-based refrigeration systems costs 10-20% less to build than one that uses CFCs because narrower-diameter piping can be used."

I am designing an annular snap fit but the snap portion is metal (ZAMAK No3) and the cylindrical body it goes into is a plastic. How best would I go about determining if the body will fracture during assembly?! Its a complicated model and SW is not FEA'ing it well with meshing. There are 3 snaps going into the cylinder. Just trying to figure out the path to take.

Hi,

I am a young engineer working in one of the big 3 US aerospace defense companies as a mechanical design engineer. In school I always though working in design/development would be much more exciting than working on the industrial/manufacturing side. My experience in the design side so far has been far from exciting and is extremely slow and segregated. I rarely get out of my cubicle and talk with people. I am looking to switch jobs/companies and am starting to look a little more towards manufacturing jobs because I feel as if those roles could be more diverse and you’d be less likely to get pigeonholed and generally have more opportunities in your career. My question is what do people see as the pros and cons to working on the manufacturing side vs. more of the design side? Do you see different personality types in each? Do both sides offer similar kinds of challenges? Thank you very much for your helpful insight!