Improving your welding?

[Arc weld]

Hoping to put this little sidebar to bed... cyclic loading indeed is a form of dynamic loading. I could be wrong (no :shocked but I think you are confusing static load with dead load. Dead load is basically the load based on the weight of the object. A static load is the dead load plus any additional load that is 'slowly' applied such that you don't create significant dynamic effects creating a shock or vibration. That additional load could be due to pressure, added mass or gravity. Anyways... back to improving one's welding and maybe even civility.

I don't know how this got into a discussion on types of loads but the simple explanation of a static load is at rest and dynamic load is moving. When a crane lifts a heavy structure like a large vessel, the load is slowly applied to the lifting lug. Should this be considered a static load? I don't think so because once there is pressure on the lug it isn't at rest anymore. I don't think a load has to be constantly moving to be considered a dynamic load. Here's something I found talking about why the World Trade Centers collapsed.

"What the conspiracy theorists apparently don't understand is the difference between static and dynamic loading. ("Static" means "while at rest," "dynamic" means "while moving.")

If you don't think it can make a difference, consider the effect of a stationary bullet resting on your chest, compared to the effect of a moving bullet striking your chest. The stationary bullet exerts a static load on your chest. A moving bullet exerts a dynamic load."

 

[Happy Gilmore]

not necessarily,,,,, trying to stay ahead of the conversation is a true indication of excitement in the subject at hand. The ones who sit back and listen *could be* wishing you'd let them play a game on their phone.

...........or they already have all the answers.

 

[dragoneggs]

I don't know how this got into a discussion on types of loads but the simple explanation of a static load is at rest and dynamic load is moving. When a crane lifts a heavy structure like a large vessel, the load is slowly applied to the lifting lug. Should this be considered a static load? I don't think so because once there is pressure on the lug it isn't at rest anymore. I don't think a load has to be constantly moving to be considered a dynamic load. Here's something I found talking about why the World Trade Centers collapsed.

"What the conspiracy theorists apparently don't understand is the difference between static and dynamic loading. ("Static" means "while at rest," "dynamic" means "while moving.")

If you don't think it can make a difference, consider the effect of a stationary bullet resting on your chest, compared to the effect of a moving bullet striking your chest. The stationary bullet exerts a static load on your chest. A moving bullet exerts a dynamic load."

Arc, I can't let this rest because we are closing in on agreement BUT!

Yes, actually a slowly applied load like your lifting lug example is actually considered a static load if the load it truly applied slowly such that you don't apply additional 'g' forces other than gravity (32ft/sec/sec). When it comes to 'testing', a static load is applied over time but the rate is very slow. For instance... in aircraft design, one (of many) design requirements is the passenger cabin must be able to withstand a 9G forward (or 9 times force of gravity) static load (emergency landing condition). To test this, one must apply the load slowly such as to not exceed the 9x force instantaneously (dynamically). There are standards governing the load rate to be considered 'static'. A general rule is .05in/min displacement of the applied load. I am no conspiracy theorist but tell me how to apply a 9g static load without moving something? Static load testing is done all day long every day. And it isn't just a matter of the measuring the weight of an object but static forces applied.

Your comment, "I don't think a load has to be constantly moving to be considered a dynamic load" is curious. I beg to differ... in the case you are describing the 'moving' at a constant rate can be static. However if there is acceleration involved then it becomes dynamic. The definition of dynamic basically means changing.

Your bullet scenario is also interesting to consider. You are now getting into the physics of momentum. Momentum is different than force. Force is a function of acceleration not speed (i.e. moving, velocity). Momentum is a function of velocity. Mass (weight) being the common denominator. Acceleration is changing speed.

I don't know how this dissertation will 'improve one's welding' but maybe someone will learn something from it. :laughing: Or maybe not.

 

[paulharvey]

This is fine (not really) for a 220 VAC only tool but, for a 110 / 220 VAC welder, appliance, etc. you will need a 4 wire / 220 VAC circuit;

Black - 110 VAC
Red -110 VAC
White -Neutral
Green / Bare - ground

I think that, "new work" 220 VAC circuit with only 3 wires will not pass inspection.

Sent from my iPad using TractorByNet

Several years ago 3 wires to air conditioner outside unit was still normal. Black, white, and bare/paper wrapped.

 

[CNC Dan]

This is fine (not really) for a 220 VAC only tool but, for a 110 / 220 VAC welder, appliance, etc. you will need a 4 wire / 220 VAC circuit;

Black - 110 VAC
Red -110 VAC
White -Neutral
Green / Bare - ground

I think that, "new work" 220 VAC circuit with only 3 wires will not pass inspection.

Sent from my iPad using TractorByNet

You can have new 220 volt work with 3 wires.
People have 6-50 outlets installed for welders all the time. And there are many others too. But you can't use the ground to get 120 volts any more.

In that case you do need to use a 4 wire plug and receptacle.

 

[Reverser]

Arc, I can't let this rest because we are closing in on agreement BUT!

Yes, actually a slowly applied load like your lifting lug example is actually considered a static load if the load it truly applied slowly such that you don't apply additional 'g' forces other than gravity (32ft/sec/sec). When it comes to 'testing', a static load is applied over time but the rate is very slow. For instance... in aircraft design, one (of many) design requirements is the passenger cabin must be able to withstand a 9G forward (or 9 times force of gravity) static load (emergency landing condition). To test this, one must apply the load slowly such as to not exceed the 9x force instantaneously (dynamically). There are standards governing the load rate to be considered 'static'. A general rule is .05in/min displacement of the applied load. I am no conspiracy theorist but tell me how to apply a 9g static load without moving something? Static load testing is done all day long every day. And it isn't just a matter of the measuring the weight of an object but static forces applied.

Your comment, "I don't think a load has to be constantly moving to be considered a dynamic load" is curious. I beg to differ... in the case you are describing the 'moving' at a constant rate can be static. However if there is acceleration involved then it becomes dynamic. The definition of dynamic basically means changing.

Your bullet scenario is also interesting to consider. You are now getting into the physics of momentum. Momentum is different than force. Force is a function of acceleration not speed (i.e. moving, velocity). Momentum is a function of velocity. Mass (weight) being the common denominator. Acceleration is changing speed.

I don't know how this dissertation will 'improve one's welding' but maybe someone will learn something from it. :laughing: Or maybe not.

Dragoneggs, great analogy as usual. :drink:

Arc, you lost this round. Admit defeat and move on. :laughing:

 

[MinnesotaDaveChalmers]

Dragoneggs - I like formulas, simplifies my thinking and comparisons

Force = (mass)(acceleration)
Momentum = (mass)(velocity)

Nothing wrong with a little physics and/or math mixed in with welding

 

[Sodo]

dragon, dragon, dragon,,,,,,
,,,,,abbreviate thine inner gearboy!

:laughing: :laughing: :laughing:

ooops my most abbreviated post ever. I'm outta town for a couple weeks you guys keep it down, OK?

 

[Arc weld]

I never thought it was a contest.:confused3: I think we're in agreement somewhat that some things considered static load could also be considered dynamic load. What if you're picking something up in a nice slow controlled way and a gust of wind comes up? When it comes to welding, I think it's better to err on the side of making it able to sustain a dynamic load if it's something that could cause a big problem if it broke. The bullet scenario is like my table scenario. I don't think something would have to be bounced up and down repeatedly to be considered a dynamic load. I think if something fell once and added considerable force, it could be a dynamic load.

 

[Happy Gilmore]

I can't believe this has gone over 24 hours without a post :shocked: