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Showing content with the highest reputation since 05/19/2019 in all areas

  1. 2 points
    Cracks do not grow by themselves. Most cracking is due to fatigue, and that requires motion. A motionless car will not crack. DrD
  2. 1 point
    Speaking of cars, in particular of the chassis, if we keep a car stopped for years, will the weight of the engine and all the components form cracks in the crystalline microstructure of the iron? if we think about a spring, if we leave it compressed for so long it will lose its ability to flex, it will not come back as before (i guess), isn't it the same for a frame that has to hold up an engine for years? perhaps there is a load limit below which the piece will return as before also being compressed for many years? What happens to the metal microstructure in these cases? Correct me if I'm wrong. if the weight of the motor has been designed to keep the deformation of the underlying frame always in the "elastic" and not "plastic" area, how can it damage the metal in the absence of external environmental attacks? thanks
  3. 1 point
    Looks like you have the dimensions of the channels (10 x 15.3). Do you know if those are inside dimension, outside dimension, or what? I would suggest you go to a steel design book which will probably give you I for the section. The loading diagram indicates that w = w(x), a variable loading, so you will need to express that mathematically and then integrate twice to get the moment, M(x). From there on, it should be easy. DrD
  4. 1 point
    The Least count refers to the smallest measurable length by the vernier caliper. It can be found by dividing the difference of 1 Main scale division by the number of divisions between two vernier scale values (usually 10). i.e 1 Main Scale Division/10.
  5. 1 point
    oil is the best lubricant because it lubricates all parts which are made by electrons and metallic parts.it serves as a self lubricant in high temperature.its serves as a incompressible component,
  6. 1 point
    Least count is the value of one division of vernier scale.Since we take the vernier value with the particular vertical line of vernier scale that exactly concides with the vertical line of main scale while measurement,we have to add this value with main scale value.For example say,n th line of vernier scale matches with a particular division of main scale,the final reading will be value of main scale reading+value of n th line of vernier scale x Least count(i.e value of one div of vernier scale).
  7. 1 point

    Force generated by running machinery

    There is no simple formula for the force you are asking about. It depends upon the nature of the motions involved. If you would like to post a drawing of your machine (or send it to me by PM), then perhaps I can help you. DrD
  8. 1 point
    Dr D. Pit bulls are some of the gentlest dogs unless they are trained otherwise. A lawyer like a politician only cares, or must force themselves to only care, about winning. How much is training, and how much is evil by their nature is impossible to determine.They present a set of information (I hesitate to use facts). The presented information is turned over to a third party judge/jury who come to a decision based on two or more biased and incomplete sets of information. I have sat in court knowing the full story and listening to what was presented which then becomes the only "truth" the jury knows. I have come to realize that we have a legal system and justice is an illusion. I would go one step further and say we have a decision system. As engineers we need to get as close to the truth to prevent danger to those using our designs. The legal system needs to reach a decision so the system can move on. And they are very slow to undo a decision even when confronted with information that would have altered the original decision. My advice about our legal system, avoid it like a disease. If dragged into it don't expect justice any more than you would expect a fair fight from a mugger. Good engineers can keep you out of trouble. A good lawyer can get you out of trouble. For the first case good is a complement. In the latter, it does not necessarily have the same connotation as the first. Praised be to God we made our livelihood as engineers.
  9. 1 point
    Many years ago, I was involved as an expert in a legal dispute. My company was suing the US Army in a contract dispute. I got a very bad taste for lawyers as a result. An Army facility had designed a mechanical system and put out drawings for the system as the basis for suppliers to bid on building the system. There were five major suppliers bidding to build these devices for the Army, and the bidding was extremely competitive. Being higher by half a cent ($0.005) per unit would mean losing the bid. My employer had the misfortune to win the bidding, and we were building this rather complicated mechanical system (around 200 parts) for about $15 per unit with many 1000s to be built. Each week's production would be declared to be a "lot," typically around 20,000 units. The inspectors would draw a random sample for testing, and if all tests were passed, the lot was accepted and the company was paid for the material. If any tests were failed (and there were about a dozen different tests), the lot was rejected and the company received no payment. Dimensional tolerances were extremely critical, and the company had taken then into account in the bidding. In suing the Army, my employer was alleging that the tolerances had been deliberately set loose for the bidding while the Army knew that closer tolerances were required in order to consistently meet all the specifications and pass the tests. The Army denied this. My job for 18 months was to demonstrate mathematically that there were dimensional combinations within the allowed tolerances that would fail some of the tests, and therefore that the Army had misled the bidders in the original contract negotiations. I did this quite fully, showing that some combinations would work while others would not, even though all were within the specifications on the drawings. I was completely disgusted by the attitudes of the lawyers on both sides. The had ZERO interest in the truth; they only care about winning the argument. They were only interested in information that supported their side of the case. If a part of my study did not support my employer's case, our attorneys ordered me to destroy that paper work and to deny that I had ever done it if asked. I refused to do that; the truth is the truth. Most of my encounters with lawyers since that time has supported my early evaluation; they are evil men (and women) intent only on winning. Truth means nothing to a lawyer! DrD
  10. 1 point

    Machine Vibration

    Actually I have personal computer, So for that I have some different tricks which will be fine for all, But I faced that same problem when I want to install my canon printer and that will be fine for all. Faced any type of issue just visit Canon Error code 1660
  11. 1 point

    Machine Vibration

    It would help to have a sketch of what you have built/propose to build, and also you must specify the frequency. The frequency is a critical parameter. DrD
  12. 1 point

    Machine Vibration

    Please explore 1.Weather machine RPM can be changed. 2.Consider resonance factor.Look for possibility of change in natural frequency of machine structure/Foundation.
  13. 1 point
    Good company will give u the abstract about the work on there home website as how they provide services for society development. Fisrt need to choose a category like pumps ( design, installation, commissioning, operation & maintaining), pipe laying. Above 2 section need knowledge in material selection, which type welding needed according to the load and the fuild that need to transfer also. HVAC is an entirely different and challenging section that one need good knowledge in thermodynamics.
  14. 1 point
    abhijeet chandak

    Machine Design Methods

    I have study Mechanical Engineering were calculator is the only tool and lots of determinations , frustration and dedications until i become one..now, I am a CAD-CAM-CAE Engineer , which i only use this tools in Engineering Design... Machine Design Procedure: Understand the Requirements: ... Analyse and Evaluate the Design Mechanism: ... Analysis of Forces: ... Design of Elements: ... Material Analysis and Selection: ... Design Iteration for Manufacturing: ... Creation of Detailed Mechanical Drawings would be happy to hear some comments and discussion from others on these matters.
  15. 1 point


    Fit_and_Dimensional_Tolerances_Mechanical_Engineering_Drawing Source Ashish K Darpe Department of Mechanical Engineering IIT Delhi Thanks to Mr. Ashish K Darpe Regards Saurabh Jain
  16. 1 point


    Presentation on Design of- Clutch Brake Belts Chain Gears
  17. 1 point
    horizontal plate is placed at what height with respect to vertical plate at the bottom...middle....at the top which is not clear in the question so cooling depends on the position
  18. 1 point
    Is there any wind? If wind blown horizontally, a vertical plate will cool faster. If no wind, theoretically it's all the same due to same exposure area. IRL, have you ever saw people drying their clothes sideways?
  19. 1 point
    because least count is the minimum value tat can be counted through vernier caliper.
  20. 1 point
    But of course , Oil or hydraulic type oil is the best type of lubricator.

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