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"Newton Meter......What is it?"

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lrperkins (146 posts)
Mar-30-02, 06:08 PM (EST) "Newton Meter......What is it?" Hello to all.I've run into a problem that involves couplers. Just what is a newton meter? And what are the recomended settings for couplers?Many thanks,Lonnie
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Subject Author Message Date ID RE: Newton Meter......What is it? BlakeTyner Mar-30-02 1 RE: Newton Meter......What is it? dekosoft Mar-30-02 2 RE: Newton Meter......What is it? kwk100 Mar-31-02 3 RE: Newton Meter......What is it? plainsman Mar-31-02 4 RE: Newton Meter......What is it? wpfan Mar-31-02 5 RE: Newton Meter......What is it? plainsman Mar-31-02 7 RE: Newton Meter......What is it? lrperkins Mar-31-02 6 RE: Newton Meter......What is it? kwk100 Mar-31-02 9 RE: Newton Meter......What is it? plainsman Mar-31-02 10 RE: Newton Meter......What is it? ctillier Mar-31-02 8

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BlakeTyner (126 posts)
Mar-30-02, 08:25 PM (EST) 1. "RE: Newton Meter......What is it?" I remember something from physics class about a "newton"...seems like it had something to do with the measurement of energy. That's been like 3 years now but I remember doing equasions dealing with newtons.Blake Harris
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dekosoft (209 posts)
Mar-30-02, 09:20 PM (EST) 2. "RE: Newton Meter......What is it?" If I remember physics correctly, a Newton-meter is a measurement of torque (literally, the Force of 1 Newton applied at a distance of 1 meter perpendicular to the radius) and equals 0.73692 Foot-Pounds. cheers,
Chip
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kwk100 (286 posts)
Mar-31-02, 01:00 AM (EST) 3. "RE: Newton Meter......What is it?" LAST EDITED ON Mar-31-02 AT 01:03 AM (EST)Yes a Newton Meter is a form of torque. The Newton, is the weight of an object (mass * acceleration), acceleration is 9.81 meters/second^2 (acceleration due to gravity, this value varies depending on your location on the planet) and the mass is measured in kilograms. According to one of Newton's 3 laws, Fnet = mass * acceleration, hence the newton is also a force.The meter is the distance from the point of rotation, to the the point of application of the force.The pound is also a force, where in a foot-lb the foot is again the distance from the point of rotation to the point of application of the load/force.Remember that only the perpendicular (perpendicular to the lever arm) component of the force applies a moment about the point of rotation.Units are the Newton Meter (N*m) for the metric system or the Foot Pound (ft*lb) for imperial imperial units.Formulas:2 Dimensional:M = r * Fwhere: r = the distance from the point of application of the force to the point of rotation, and F is the force.3 Dimensional:M = r * F = |x......y......z.| - Direction
|rx.....ry.....rz| - Distance along specified axis
|Fx....Fy...Fz| - Force along specified axisMoment in the x direction: (ry * Fz) + (Fy * rz)
Moment in the y direction: (rx * Fz) + (Fx * rz)
Moment in the z direction: (rx * Fy) + (Fx * ry)This is solving for the moment using the matrixDiesel Industries
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plainsman (785 posts)
Mar-31-02, 03:08 AM (EST) 4. "RE: Newton Meter......What is it?" LAST EDITED ON Mar-31-02 AT 03:29 AM (EST)I don't think there is a simple answer to your question about coupler settings. I can explain the amount of force needed to brake a given grade coupler in both tension and shock, but this does not seem to convert directly into the proper settings in the sim. Based on a lot of testing, the following seems to give the best correlation of behavior to actual grade C couplers in good condition:
Spring (
Stiffness ( 1e6N/m 4.8e6N/m )
Damping ( 1.2e6N/m/s 1.2e6N/m/s )
Break ( 1.8e7N 1.8e7N )
r0 ( 20cm 30cm )
)
Velocity ( 0.11m/s )
)
For grade E in good condition,
Spring (
Stiffness ( 1e6N/m 4.8e6N/m )
Damping ( 1.3e6N/m 1.3e6N/m )
Break ( 2.4e7N 2.4e7N )
r0 ( 20cm 30cm )
)
Velocity ( 0.11m/s )
)
If you operate on routes with track and switch problems, it may be necessary to use the following:
Spring (
Stiffness ( 1e6N/m 4.6e6N/m )
Damping ( 1.2e6N/m 1.2e6N/m )
Break ( 5.4e7N 5.4e7N )
r0 ( 20cm 30cm )
)
Velocity ( 0.12m/s )
)
Hope this helps,
Bob
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wpfan (259 posts)
Mar-31-02, 03:22 AM (EST) 5. "RE: Newton Meter......What is it?" Is bood supposed to be a cross between good and bad or is it just a typo. Around this forum one can never tell. I'll have to go back and dust off some of my physics texts if I can ever find them. As of lately the only thought I had ever given to torque is where to set my wrench.The voice of insanity in a seemingly normal world. Remove | Alert Edit | Reply | Reply With Quote | Top
plainsman (785 posts)
Mar-31-02, 03:31 AM (EST) 7. "RE: Newton Meter......What is it?" Thanks, sometimes my fingers get tonguetied, particularly at 2:00 in the morning.
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lrperkins (146 posts)
Mar-31-02, 03:29 AM (EST) 6. "RE: Newton Meter......What is it?" My thanks to all.And yes, this information does help. And yes, I'm working on a project with track and switch troubles. And it's driving me nuts. I've worked on four other projects and this is the first time that I've run into the switch and coupler problem. What I don't like is that it doesn't cause trouble all of the time.Thanks again for the help,
Lonnie
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kwk100 (286 posts)
Mar-31-02, 02:39 PM (EST) 9. "RE: Newton Meter......What is it?" LAST EDITED ON Mar-31-02 AT 02:45 PM (EST)From the units I see in the above post, it seems that we are not actually talking about torque, as the units for torque is the N * m and above we have the N / m and N / m / s.Rather, 1e6N/m relates to the spring constant. According to the formula, F = -kx therefore, F/x = -k, where F is the force applied to the spring, of coupler in this case, and x is the distance that the spring is streached, we are assuming that the coupler lies along the x axis, so a streatch or pull on the coupler is in the positive x direction. This is Hooke's Law. The units are N/m. The minus sign indicates that the force is always in the opposite direction of the displacement on the opposite end, (free end of the coupler, the end that is NOT attached to the car). If there were no minus sign, like in the example in the above post, we are measuring the force applied in the direction of displacement of the coupler. In other words, if you are pulling a car forward, we are measuring the force that the locomotive applies upon the cars coupler. The value k, which is the spring constant, has no units and should be given.All that Mircosoft is representing by the stiffness, is the maximum allowable force, f, that the coupler can support without failure when it is stretched a certain distance x.N/m/sThis again is another equation to do with the spring constant, or stretchiness of the coupler. I will have to look up this equation, but I am assuming that it may be that F=-kv where F and k are the same as above, and v is the velocity measured in m/s. If you solve the above equasion for k, you obtain the units, N/v = -k or N/m/s = -k. Where in the case of damping, the k would be the resistivity constant, that the spring applies in the opposite direction of the applied force F (F is in this case directed towards the end of the coupler tht is attached to the car). Careful on this one, I may be incorrect, I will look through some of my texts, inorder to supply you with the correct answer.Diesel Industries
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plainsman (785 posts)
Mar-31-02, 04:04 PM (EST) 10. "RE: Newton Meter......What is it?" "All that Mircosoft is representing by the stiffness, is the maximum allowable force, f, that the coupler can support without failure when it is stretched a certain distance x"I don't think this is correct. I believe the stiffness line refers to the amount of force needed to compress a spring a certain distance. If this is too light, the spring will reach its full travel too easily, and upon hitting that point, no longer functions to dampen shocks. If this is too great then the shocks will not be absorbed by the spring enough to protect the coupler. The dampening line refers to the mitigation of the impact of the force (shock absorption). The break line is a force, which if applied directly to the coupler, would cause failure.
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ctillier (122 posts)
Mar-31-02, 02:33 PM (EST) 8. "RE: Newton Meter......What is it?" I think if you're dealing with couplers you meant a Newton PER meter and not a Newton-meter. As others have said a Nm is a unit of torque, and can also represent energy (as a scalar) since 1 Nm = 1 Joule. But I digress.Newtons PER meter (N/m) is the unit for a spring constant (i.e. the stiffness of the coupling). If you multiply this number by the extension of the coupling in meters you get the tension in the coupling.--
Clem

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