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  1. 15 likes
    As an older engineer, I am rather dismayed by what I see as the results of engineering education today. I have seen most young engineers come out of their college degree programs with a modest familiarity with come CAD program and a related Finite Element program, and an almost complete lack of capability to analyze machine components without the use of FEA. Thus they are unfamilliar with basic design calculations relating shear stress in a shaft to the power being transmitted, the shaft sped and the shaft diameter. Instead, they want to create an FEA model and run the numbers that way which is simply not the way you make any progress in designing a machine. It is certainly true that FEA allows for a good detailed stress analysis of complex geometries, something that was not possible in general by the older methods. But the results obtained are highly dependent on the skill of the user in applying the correct boundary conditions, something that is a bit of an art in itself. I have observed a tendency to even want to use FEA to do kinematics, rather than using simple, rigid body kinematic relations. This seems like pure foolishness in almost all cases. Are we not developing a tendency to lean too heavily on the computer, rather than to learn to think as engineers? I would be happy to hear some comments and discussion from others on these matters.
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    whel! I have Instalation files and user manual! If its intresting for you tell me to send 4 u!
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    well in except that both of them are Dassault Systèmes's products . there is a little difference between them. Basically , Solidworks is a CAD (computer aided design) software - the best of it's kind i assume - Simple to manipulate , easy to learn and used by almost every single industry in the world . CATIA is A CAM software , indeed it's better than solidworks in some modules such as surfacing and kinematics. But the main idea is that in CATIA you can not only create a mechanism , but a factory in which it will be produced, the machining processes required, and even you can simulate ergonomics studies as well, like weather the current layout of a plant will be comfortable for workers to work or not. So you can simulate the whole thing within a virtual reality, including, and of course, rendering. However CATIA is almost exclusively used in Aviation and Automotive industries. So there is no doubt you need to learn them both ... because let's say if you want to create an airplane Use CATIA to create the surface and to simulate the manufacturing process and Solidworks would easily handle the engines
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    Well there is no such "best lubricant", I guess. But there is always the best solution for the system that you are working on . Obviously you can't use water ot grafpite to lubricate a CD player. And you can't use magnetic field to lubricate a turbo jet either . It's all matter of compatibility, and a little bit of engineering ,
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    http://autocadtutorialsbd.com/ArcAn arc is really nothing more than a portion of a circle, so drafting one is very similar to drawing circles. The biggest difference is that instead of just defining the radial size of an arc, you also need to define where the arc starts and ends. You can execute the Arc command from a toolbar or by typing “arc” at the command line. Auto CAD provides many different options for defining your arc, which you can examine in detail through their help utility. Below, I’ve listed the four most commonly used methods of arc creation, and given a graphic example of each in the example above. The various options can be accessed through the pull down menus or by selecting the appropriate options from the command line as shown above. Three Point Arc (3P):This is the simplest way to draw an arc but it’s also the least exact from a drafting standpoint. You simply select the start, midpoint and endpoint of the arc on screen. Start-Center-End:This works similarly to the Start-End-Radius command above, but you select the center point of the arc on screen instead of typing a radius. Start-End-Angle:This method is the one of most commonly used. You select the start and End of the arc on screen, and then you can give angle of arc to complete the arc. Start-Center-Length:Allows you to pick the start and the center point of your arc, and then complete it by entering the linear distance between the start and end points. Start-End-Radius: This method is the one most commonly used. You select the Start and End of the arc on screen, and then you can either drag the cross hairs or type an exact radius to complete the arc. Start-End-Direction:This method is the one of most commonly used. You select the start and End of the arc on screen, and then you can give direction left, right or top, bottom to complete the arc. EllipseTwo axis values are required for an ellipse. Ellipses can be regarded as what is seen when a circle is viewed form directly in front of the circle. Ellipse is measured in terms of two axes there are major axis and minor axis. You can draw ellipse in various way such as using axis, end option or center option. Draw procedure of ellipse: Command: Ellipse8 Specify axis end point of ellipse Specify other end point of axis (Say essential dimension) 8 Specify distance to other axis (Say essential dimension) 8 Hatch Boundary Hatch by typing H <ENTER> . When you start the command, you will see this dialog box appear: Now you want to pick the area to be hatched swatch box. Pick somewhere when hatch pattern plate say (ANSI, Other Predefined, ISO)Select Hatch then OKAdd pick pointPick Internal point then<ENTER>.Select preview for the hatch are ok but when we do not see hatch so set the scale of the hatch and then finally, see the Preview button to see if this is what you are after, it should match your desire work. Note: When hatch pattern does not match your work what can do you? Hatch Edit Select hatch which you drawRight clickHatch EditChange scalePreview button to see if this is what you are after, it should match your desire work. see more details
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    Recently I was looking at the well known textbook, Mechanical Vibrations by S.S. Rao. I found an interesting problem there that seemed to be worth investigating further. The attached note is the result of that investigation. I challenge all of you to work through the details! DrD TwoSprings.pdf
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    The video of the walking machine is very cool. Great job!
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    The DIAGRAM itself is of very little use, in my opinion. The information it contains, however is another matter. When you speak of a diagram, I presume you refer to something actually drawn on paper, in which case, to get numerical data from it, you must scale the diagram. This is never very accurate. A knowledge of velocities and accelerations is essential if we are to describe the dynamics of a machine system. All of this can be done mathematically, and it that form, this information is of great value. We often need to calculate the forces in various components to determine their required strength. This means that we must be able to write a full mathematical description of the system dynamics, and that always involves velocities and accelerations. To sum up then, personally speaking, I think the diagram is next to useless, but the knowledge of velocities and accelerations is essential for design. DrD
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    Did you already try etoolbox? https://www.intellicadms.com/. What do you think about it?
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    Universal solvent ,water can be used as lubricant when compared to oil..because some oils damages the operating system like cutting tool and (due to chemical reaction takes place between them leads to corrosion...... some times metal diffusion may takes place )etc...water is less economical and esaily available ..now adays people are using wateremulsifierst to get a desirable properties like non-corrosive ness,viscocity, high heattransfercofficient through it etc....Thease may be the some reasons universal solvent is used as lubricant in many industries
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    Greetings. Newer generation of motorcycles has EBC(Engine brake control). Can someone explain me how do they change amount of engine braking with a press of the button. Only information i found is that this EBC unit works in combination with slipper clutch but i dont understand principle of the EBC unit. Is it operating by altering the valve timing, regulating throttle position or something else.
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    Everything depends on the type of loading in the application, but in all likelihood, no, this does not sound like a good idea. DrD
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    Hello everybody, I am a auto mechanic in training and I have been very perplexed by in how the rotary engine was junked before it could fully blossom into a real and amazing form of engineering I have a partial redesign which follow the aviation propeller engine. I have been thinking of how I could increase the efficiency and limiting the pollution output; I believe I could achieve that by having the exhaust pass from the first piston to the second piston and mixing it with a lower concentration of outside air to burn the fuel completely. Although I am still not sure what else I could do to enhance it further. Any ideas would be great but I am also trying to make the engine compact and as cost efficient as possible.
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    FEA usually stands for finite elemental analysis. A very simple explanation would be that you take a 3D model that you want to analyse, say a 3D model of a wrench, and have the computer FEA software break it up into "particles", which are the finite elements. Then you set boundary conditions, such as a torque on two faces of the wrench. The software will then solve a relevant set of fundamental equations for each particle and add all the solutions together. In the case of the wrench you could have the FEA software tell you the stress and strain everywhere on the wench, or the location of the highest stress concentration. This could then be used to create an optimized design for the wrench by adding material in areas of high stress or removing some in areas where it is unneeded.
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    FEA stands for Finite Element Analysis. The FEA approach breaks a domain into many small (but not infinitesimal) subdomains or elements, and then attempts to satisfy the describing equations within each element. The result is a very large number of usually linear equations to be solved simultaneously to obtain the describing values in each element. There are many good books and countless papers on this subject. Go find some of them and read more to obtain a greater understanding. DrD
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    Hi all, As most of you know, quick aluminum extrusions are great to save design and manufacturing time, but have some downside in term of quality level and durability (screws tend to losen-up overtime) (see "Design A" as typical quick extrusions and bracket that can be bought on McMaster) In "Design A", positioning of the 90' bracket in the groove is done by a "straight locator" creating a slack of 0.025'' In "Design B", positioning of the 90' bracket in the grove is done by a "tapered locator" eliminating the slack as the screw is tighten. Do you think that if "quick extrusions" were done like "Design B" we could use them for high-precision machines (e.g., CNC machine) or tooling? Thoughts?
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    Your question is a bit too broad to be answered intelligently. You ask if extrusions like "B" could be used in high precision machines such as CNC or tooling. I'm going to take a shot at this in a very general way. Design B may be adequate from the stand point of unloaded positioning, but the bigger question (as I see it), is "Will it be stiff enough?" You might then ask, stiff enough for what, which puts us right back where we started. You cannot make a blanket statement to the effect that "this is always good enough," or "this is never good enough." It depends upon the situation. Any material that is soft enough to be extruded will have a relatively low value of Young's Modulus and yield point. That means that, even for an optimal cross section, the beam stiffness is limited. When you get to the point where you can extrude 4140 steel, then maybe so. DrD
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    I would like to know hte background of this question prior to offer any assistance... ...whilst more than happy to help, it sounds a little too-much like a college/univeristy homework question!
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    The use of governor is to maintain the proper torque in a vehicle by providing required amount of fuel as per load.
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    blower is a type of fan and blower working like a centrifugal pump. blower have 1.1 to 1.2 pressure ratio on other hand fan have below to 1.1 pressure ratio blower used for high pressure air like in furnaces Fan Blower Definition A fan circulates air around an entire room, or space. A blower circulates the air only on the specific or pointed area. Pressure It is uses less pressure to produce large amounts of gas. It is uses high pressure to produce large amounts of gas. Pressure ratio The ratio of pressure is below 1.1. The ratio of pressure is from 1.1 to 1.2. Air area It provides air in the complete area. It provides air in a specific location or point. Types Axial flow fans. Centrifugal fans. Cross- flow fans. Centrifugal blowers. Positive-displacement blowers. Consists of It consists of a motor and blades, which run of electricity. It consists of a fan, outer cover, inlet, out-let.
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    The purpose of the governor in the diesel engine is to regulate the amount of fuel going to the fuel pump and eventually the engine to maintain a desired rpm..
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