Trailer and cargo masses.

Killerhangar
Posts: 301
Joined: 18 Nov 2013 06:53

Re: Trailer and cargo masses.

#41 Post by Killerhangar » 09 Oct 2015 21:23

48 tons gross weight and legal. In EU. You can haul your empty trailer's its full or nothing. :lol:

What I'm trying to say that, so what if its over 40t? Actually, in the game you could see the weight of your truck and the trailer+load and you could get fines from overweight? (And that with 3 or more axles you could haul more) and you would need some kind of license to haul oversized stuff?
#scandirammer #swedenskåperz #finland

Calzone
Posts: 690
Joined: 10 Aug 2013 20:10

Re: Trailer and cargo masses.

#42 Post by Calzone » 04 Dec 2015 21:25

I would be more curious how SCS distributes the cargo weight over the trailer physics wise. I've done calculations on when the third truck axle would actually be needed, but for those calculations I made the assumption that the weight is equally spread over the trailerfloor. This is a situation that is not very common, atleast, from what I've seen.

Weight distribution also plays a major role in maximum cargo loads, so it's not one to forget.
Gigabyte GeForce GTX 1070 Windforce OC 8G / AMD FX8350 Black Edition @ 4.0GHz / 2x Corsair XMS3 4GB 1333MHz DDR3 / Corsair CX500M / ASUS M5A78L LE / Fractal Design Define S

User avatar
Cadde
Global moderator
Posts: 8641
Joined: 24 Apr 2013 18:08
Location: Have no fear, i am from the internets!

Re: Trailer and cargo masses.

#43 Post by Cadde » 04 Dec 2015 21:56

Calzone, I'd say it's center of mass is at the center of the box that makes up the trailer. I could be wrong and Blender users could probably check to see if there's a center of mass anchor/node.

In the simplest of physics, this mass is being applied with a downward force of G (for gravity) and then is counteracted upon by bones attached to it (each axle is a bone and the trailer pin is a bone) which when the mesh (box) passes the limits of these bones adds force with an offset from the center to keep the thing "floating" in 3D space. Add various spring and dampening modifiers as necessary to said counter forces.

There's always a problem with this approach and you won't likely ever get away from it completely due to performance reasons.
One is that all forces must suffer floating point precision errors.
The other is that the physics model is very simple compared to high grade physics simulations for the above mentioned performance reasons.
And third is that you will always (due to the first 2 especially) have situations where the physics isn't entirely solved on that one timeframe. Some games run extra cycles to fine tune the results but that cuts into the limited frame time available and generally leads to skipped simulation frames for certain objects, slowing down time or low FPS. Whichever the developer feels like sacrificing.

Finally, there's always the risk of endless loops in the physics engine and these cases must be handled in a deterministic fashion which ends that loop.

All of the above means you can't really work out using real life models how the forces applied on an object affect the final outcome. You can only do so with the actual physics model used in the game.
I am not sure even SCS could tell you exactly how the "cargo weight" is applied across the whole trailer body (taking into account axles and other bones) as it's complicated and not realistic nor straightforward.
There's too many ways in which any specific model can be thrown out the window if X is true or Y is in effect.

So, just think of it as a box that is being pushed down geometrically that intersects the axles and fifth wheel which in turn pushes it back up with angular forces.

Image

There are of course other forces at play here too. Acceleration and braking and cornering etc.
But yeah, they follow a simple center of mass model from my observations. The whole trailer body is one solid box that falls to earth and is rotated accordingly. It is of course also locked on a hinge with the tractor so any forces applied on the tractor affects the trailer but not so much vise versa as that would be computationally unwise and would cause physics spazzing in the game. I am not saying the trailer doesn't affect the tractor, it sure does but it doesn't affect it as much as the tractor affects the trailer for physics simulation reasons.

Of course, i am no dev and i don't have the sources. Even if i had the sources i wouldn't understand the model. I am merely going by personal experience and observations in the game.
ImageGreen text = Moderator action.
ImageWhite text = Opinions and general banter.
PEBCAK errors... PEBCAK errors everywhere! If my life had a log file, it would be filled with PEBCAK.

Calzone
Posts: 690
Joined: 10 Aug 2013 20:10

Re: Trailer and cargo masses.

#44 Post by Calzone » 05 Dec 2015 17:07

The situation you sketched is exactly the situation I used for my calculations ;) Thanks for explaining the way the game would handle those physics though, I'm just a simple Automotive engineering student, so I have no idea how games handle that stuff :lol:

Of course acceleration and decelleration play a role in the physics, but the goal of my calculation was just to see how much weight would be needed before I needed to use the mid lift axle on my 6x2, because I try to use it as realistically as possible :) Most of the time truck and trailer combinations are weighted static, so I didn't take acceleration and decceleration in acount. Maybe something I should, because in a static condition with the box type center of gravity you could haul 35 tons (Schmitz Cargo Bull trailer weight included) before the third axle is needed.

Come to think about it, maybe it would be cool to have a topic sticky'd where all the rules per EU country are written down for when to use wich axle and maximum GCWs, because that seems to differ per country too.
Gigabyte GeForce GTX 1070 Windforce OC 8G / AMD FX8350 Black Edition @ 4.0GHz / 2x Corsair XMS3 4GB 1333MHz DDR3 / Corsair CX500M / ASUS M5A78L LE / Fractal Design Define S

User avatar
Cadde
Global moderator
Posts: 8641
Joined: 24 Apr 2013 18:08
Location: Have no fear, i am from the internets!

Re: Trailer and cargo masses.

#45 Post by Cadde » 05 Dec 2015 18:30

Indeed it does, in Sweden you are allowed to carry more weight on the entire consist than most other countries. In certain areas of the country you can see road trains (yes, not that different from Australia) with 3 trailers or more on a single tractor.
You won't see that in the rest of Europe any time soon.

Maybe in the future we will see more of this?
In the meantime, this is pretty common...
Image

I know it doesn't relate to your question on how many axles you need etc but for the loads we normally carry in ETS, the number of axles used doesn't generally play a big difference in the real world. In Sweden there's three classes applied to roads and bridges.

BK 1 (Bärighetsklass / Carryclass) where you are allowed 11.5 tons on a driving axle and 10 tons on others. 60 tons in total for the consist.
BK 2 where you are allowed 10 tons per axle with a total of 51.4 tons and...
BK 3 where you are allowed 8 tons per axle with a total of 37.5 tons.

So using ETS 2 cargoes, the heaviest at 25 tonnes + trailer 6 tons + tractor at ~10 tons for a total of 41 tonnes. Assuming 5 tons on the frontmost axle and equal distribution on 4 other axles you have 9 tons per axle. This lets you go anywhere except BK 3 roads/bridges etc. All of this also depends on the distance between axles of course. You can't have 6 axles over 6 meters with 41 tonnes on it obviously!
Carrying any load that is less than 24 tonnes (including weight of trailer) generally means you can go pretty much everywhere on 3 axles only. It's pretty rare to see tractors with more than 2 axles in use here.
ImageGreen text = Moderator action.
ImageWhite text = Opinions and general banter.
PEBCAK errors... PEBCAK errors everywhere! If my life had a log file, it would be filled with PEBCAK.

Calzone
Posts: 690
Joined: 10 Aug 2013 20:10

Re: Trailer and cargo masses.

#46 Post by Calzone » 05 Dec 2015 22:10

That's pretty much why I would like a topic with the differences in the ETS countries, because here in The Netherlands the rules are kinda different. As far as I know, any truck can go on any road it wants as long as it complies with the following rules:
- GCW = 50.000 kg
- Front axle load atleast 1/5th of total truck mass
- Kingpin pressure trailer atleast 1/5th of total trailer mass
- max. 11,5 ton on driven axle
- max. 10 ton on non-driven axle
- max. 18 ton on tandem axle with atleast one driven axle when distance between axles is between 1,30 and 1,80 meter (Standard Scania's have 1,35m distance)

Some roads and bridges have signs that say only a certain axle load is permitted, but that's mostly on old roads and bridges where trucks wouldn't come anyways.

I'm no trucker though, this is just what I've found on the RDW site (Dutch department of transportation).

Would be nice but complicated to have cargos in ETS2 that can only be transported within a certain country because of laws :mrgreen:
Gigabyte GeForce GTX 1070 Windforce OC 8G / AMD FX8350 Black Edition @ 4.0GHz / 2x Corsair XMS3 4GB 1333MHz DDR3 / Corsair CX500M / ASUS M5A78L LE / Fractal Design Define S

Pers Kärpänen
Posts: 168
Joined: 22 Aug 2013 07:48

Re: Trailer and cargo masses.

#47 Post by Pers Kärpänen » 27 Feb 2016 09:53

And then Again... On those trailers with two or more containers, the center of G (gravity) because the weight doesn't have to spread equally to the length of trailer.

And then on. Not all the containers necessarily have the same load thus they are on the same trailer. So there should be some sort of share-out also in the waybill or what ever you call the Cargo name seen on the market and on the navigator declaration.

And those container tanks are yet to be seen. Though they are more common on liquid transportation than those tankers/tank trailers seen there for so long.
Believe in three Capitals
DAF - MAN

User avatar
dar4eto
Posts: 155
Joined: 16 Nov 2014 12:25

Re: Trailer and cargo masses.

#48 Post by dar4eto » 07 Apr 2016 11:36

I just wish in ETS2, trailer mass affect in truck steering.
Makedonski_Kamiondzija

User avatar
SiSL
Beta tester
Posts: 6707
Joined: 27 Oct 2013 06:23

Re: Trailer and cargo masses.

#49 Post by SiSL » 07 Apr 2016 11:41

^^ While I agree to that, it is hardly an issue with modern trucks anymore...

Only if load was not tied properly may be...

User avatar
CAElite
Posts: 110
Joined: 05 May 2016 04:31

Re: Trailer and cargo masses.

#50 Post by CAElite » 24 May 2016 23:56

Eh, well with a modern steering unit you dont feel the extra weight pressing on your steers you still feel the effect of the momentum through your chassis, especially downhill. If you are on a ~10% downhill incline with a 44ton GVW then you will notice the nose weight of your trailer pushing the fifth wheel foward. This causes a slightly heavier yet fidgty feeling through the wheel and increases tyre slip understeer into corners leading potentially to oversteer (jack-knife) if brake is applied.

It is a pretty terrifying feeling if you are inexperienced. American style long noses handle it much better due to the longer chassis.
Last edited by ohaha on 25 May 2016 19:29, edited 1 time in total.
Reason: Quote removed. [2•4]
IVECO - It Vibrates and Everything Comes Off. | DAF - Don't Ask for Features.

World of Trucks

Post Reply

Return to “General discussion about game”

Who is online

Users browsing this forum: No registered users and 12 guests