Search results

  1. A

    How materials breaks

    What you are describing is an entire academic field called Fracture Mechanics, covered by many engineering courses. The field is vast, and the process of fracture will depend on the material, loading and test conditions, etc. Start with this link, and there are also numerous books and papers on...
  2. A

    Engineering Competitions like DARPA?

    There are also a number of Micromouse competitions worldwide, which cover a broad range of engineering disciplines.
  3. A

    Converting uniformly distributed load applied to a surface on an angle to point loads

    Have you tried calculating the resultant force of the distributed force (which by the looks of your drawing will be at the middle joint, in the -y direction) and then calculated the forces in each truss due to the resultant force? Remember, the moment caused by a distributed force can be...
  4. A

    Need help with arduino sampling voltage and current

    No worries! Well, what serial functions are you using at the moment? An easy, but slow, method that I sometimes use when I need to graph data is to use the Serial.println( ); function, and then simply graph the data I get versus time in some other software (Excel)
  5. A

    How a vacuum works

    This should also be helpful:
  6. A

    Inflate aluminium tube to increase it’s strength?

    Also, it will depend on the loading on the beam. Pressurizing the thin walled tube induces axial and hoop stresses. Thus you increase it's compression strength in the axial direction, but be very careful that the hoop stresses are not increased so much that you exceed the yield strength causing...
  7. A

    Need help with arduino sampling voltage and current

    Sounds like you want to do some analog input sampling. Remember the Ardunio can only measure inputs between 0-5V, so you want to design a circuit with a voltage divider and some diodes to ensure that the input to the Arduino never exceeds the value it can take (trust me, you'll fry the thing if...
  8. A

    I want to do an egg drop by submerging the egg in fluid. Which fluid is best?

    Also, you'll want to ensure a high enough viscosity of the liquid to ensure that the egg does not hit the bottom of your container at a high speed. Thus I would test a high viscosity liquid with significant buoyancy. Hence, basically your egg would only be submerged on impact, but not so much...
  9. A

    Rate of energy release by Polonium-210

    "Activity" (in Bq) is the number of nuclei that decay per second. "Energy" is defined as the energy per nucleus released. As defined in the answer here, the units after the conversion will be in joules (MeV * 1.6 × 10-19 = Joules). Hence, (number of nuclei / second)*(joules / number of...
  10. A

    C/++/# C++ Problem with accessing elements of a character

    Thanks guys. Indeed, I was quite confused about characters and character arrays, but I think I've sort of got the hang of it now. Also: This solved my issues with reading the correct data, as without the 'NULL' the software just kept on storing garbage into my fx, fy and fz arrays.
  11. A

    C/++/# C++ Problem with accessing elements of a character

    I'm still having a few problems though. The output to "buff" is: <error>,xxxxxx,xxxxxx,xxxxxx,xxxxxx,xxxxxx,xxxxxx<cr><lf> Now, what I'm trying to do is the store each of the "chunks" of data between the commas into separate chars. However, using the code above, buff[i+2]; does not seem to...
  12. A

    C/++/# C++ Problem with accessing elements of a character

    Hey guys, I'm having trouble with sampling data from a force/torque sensor. I'm using Serial Com to receive the readings from the sensor, which is stored in a character of with 45 individual elements. What I'm trying to do is to pick out pieces of these data and store them separately. I'm...
  13. A

    Space in plastic to fit a ball bearing?

    It all depends on the type of fit you are looking for, and the available tolerance for the drilling of the hole. If you are going for an interference fit, it's probably safe to assume that the plastic will be compliant enough for a less than 10mm hole (again, this all depends on the tolerance of...
  14. A

    How can we combine metal and fiber together?

    Are you talking about a sheet of metal (steel or aluminium?) and a sheet of CFC? In that case some form of epoxy should work. Best results would obviously be achieved if you use the epoxy on overlapping faces of the sheets, i.e. not end to end. This wille depend on the expected loading...
  15. A

    Problems for Robotics in Petroleum Engineering

    Hey guys, I'm looking to do a robotics/mechatronics project (topic still not decided), and I'd like to focus on a problem within petroleum engineering. However, I'm not too experienced within petroleum production (more of a robotics background), and I'm looking for areas where robotics are...
  16. A

    Need help finding plug/socket cable connectors

    Hi guys, I'm working on a project (a micromouse to be specific), and need an easy way to connect and disconnect some wires. The picture below shows some connectors I took from a computer fan, but I really need connectors with 4 pins instead of two. Can anyone help me with what these are...
  17. A

    Volcanic ash stops flights

    Well, I've found some predictive maps, like this one: But looking for one where on can see how the winds are directing the ash
  18. A

    Volcanic ash stops flights

    Does anyone know where one can find satellite images of the ash cloud?
  19. A

    Torque in bolt

    Can you elaborate a little? What kind of screws are you using?
  20. A

    Control System

    We have no gyro on the system. The craft will be driven by the primitive mechanism of two fans; one horisontal (providing vertical thrust), and one vertical (providing forwards motion and potentially vertical thrust by use of an air divider). The direction will further be determined by rudders...
  21. A

    Control System

    Hi everyone, I'm designing a light-weight hovercraft (2 light fans, 4x1.5 V batteries, 30x20cm in size). It needs to travel 6m straight ahead, then make a 90deg turn to the right and travel on for another 2m. The problem is that the craft must make this turn ON ITS OWN, meaning that there...
  22. A

    Potential Computer Engineer

    I suggest you try reading some books on programming and computers (but you might have done so already), and experiment a bit with different programming languages and see if you find it interesting. A little warning though, programming can be quite difficult and daunting at first, but just play...
  23. A

    What color would a green cloth appear in yellow light

    A green cloth reflects both blue and yellow light, so if you shine "yellow light" on it (ie light where all other wavelengths have been removed, including blue obviously) the cloth would only reflect yellow light and thus appear yellow.
  24. A

    Pressure in outdoor water tap is no good

    Well, if I understand this right, the new valve has a bigger diameter than the previous one. Is this correct? I also assume the water supply has not been changed? Now, careful not to mix force and pressure! Force is due to the water supply, while pressure is the force divided by the area of the...
  25. A

    Structural Design (Beams)

    Hi Claire, sure you have the correct formula for deflection? My notes asy L^4 not L^3.... Anyways, the expression of moment at any part of the beam is M = (w*L*x)/2 - (w*x^2)/2 as moment is the integration of the shear force (look at the bending moment diagram compared to the shear force...
  26. A

    Fluid Statics Problem

    Ok, I've come across this problem in fluid statics, but seem to be getting the integration wrong: "A semicircular plane is submerged vertically in a homogeneous liquid with its diameter d at the free surface. At what depth s is the centre of pressure?" The answer should be s = (3*pi*d)...
  27. A

    Does random exist?

    Just a quick note; if interested in the mathematics of chaos and randomness, read the book "Chaos" by James Gleick
  28. A

    Global Warming

    That is a good example Skyhunter. However, the sad part of the tale is where the aerosols come from of course. There has been drawn quite good links between global dimming and seismic activity in the same period of time(vulcanoes errupting all over the place, to put it bluntly), as well as...
  29. A

    Space temperature

    Actually your question is well justified, yet there is also an answer to it. The temperature of the universe is determined by microwave radiation remaining after the Big Bang. Tedious measurements have found that this radiation is the same from every direction of the Universe. So even though...