Another one of my weird ideas. Any engineers reading this?

I meant cause more damage to the other vehicle and it's occupants.

 

LOL, I get it. I think that as long as I do not cause an accident, I would much rather have more protection at the expense of not being able to absorb more energy.

 

I am also an engineer and would have to agree. There is a reason your vehicle is designed the way it is. One word comes to mind when I read this idea during a head on crash...”thump”...

 

My friend, this is not 1960. Nascars, Indy cars, F1 cars, etc are all designed to crumple, just like our Tacoma and everything else. More steel is not more better if you want to survive a crash. http://nascar.factexpert.com/1211-nascar-accidents.php

 

@hiPSI This makes sense, but is that impact negated by welding on plates? I know we don't have the calcs and whatnot, but from the seat of my pants, I'm thinking the impact isn't all that much if plates are welded where the mounts were cut.

Now, just cutting and painting? No reason to do that.

 

I reference your quoted article. Read the section “Roll Cage”. The safety cell, it is not designed to crumple.

 

Man, my wife would kill for your job. The AF has her in med/surg and she's dying of boredom; dispensing meds and fluffing pillows all day.

 

Your assumption is correct. I would view a large aluminum bumper as extending the crash bar's capabilities. It WILL fail before the steel frame, meaning you have more crumple zone from a larger area of inelastic collision. This is safer for the occupants, more durable than the factory bumper in any collision, but less durable than a plate bumper in low-mid speed collisions.

Upward movement will spread the collision out, lessening the impulse of the collision and decreasing the rate of change of momentum. Airbags will be less likely to go off, and occupants will be less jarred. The other car though... Will be bad off. Missing their crumple zones, the taco may end up in the trunk or backseat of another car, doing way more damage.

With any aftermarket bumper, you're going to do WAY more damage to another vehicle being hit relative to the factory bumper.

This is literally reducing the size of a rigid safety feature on the truck. The cab mount is not a crumple zone, it is static. Leaving it open after a chop is foolish, but a proper welded plate does mitigate it greatly, especially considering at the base, the cab mount is still more or less the same size.

There are multiple dynamics at play here with a CMC:
1. The shape of the cab mount changes. This affects deflection. Most CMCs still angle down, whereas the factory cab mount protrudes. I am unsure of the design decisions for making it protrude, so I can't really say how this affects safety without speculation.
2. The width of the cab mount decreases, which reduces the required force to shear or bend it, even with the CMC plate in place. The physics associated with this is known as a beam deflection calculation, which is fairly common, but isn't fully accurate here since the cab mount isn't a perfect beam.

Either way, for a CMC to affect vehicle safety would require a very substantial impact, definitely totaling the truck. If it was a concern, you could brace the cab mount from behind, but again, that would affect the dynamics of the crash if the cab mount is supposed to shear. I wouldn't stress about a CMC, I'd again just not speed, not drink and drive, and not text and drive.

 

Is there a mod for being able to use stock front and rear bumper and use a hi lift jack?
Ive seen the wheel adaptor strap for hi lift jack, and the option for frame mounted sliders.

 

Honestly, I can appreciate the "I'll take no risks for my family" perspective about vehicle modification, but I kinda feel that if you really take that to the extreme you might just miss out on a lot of life's pleasures which could also have a negative impact on the quality of life for your family. It's all up to us to balance things out.

 

This is something I would not do...

The OEM bumpers are in no way able to support the weight of your vehicle.

 

Not that you couldn't figure something out, but the factory bumper covers are painted/coated and anything you do to put 1200lbs of lifting force (assuming you are lifting 1/4 the weight of the entire vehicle) on that cover, you are going to damage at least the paint.

 

exactly.

 

Mechanical Engineer here. Regarding the CMC, I cant help but think that, as the reason a CMC is done is to clear a larger tire, the CM would still do its job, as the larger tire will still interfere with the CM in a similar manner as stock. Also, the welded plate at the CMC angle is probably at least as strong as stock, if not stronger (if done correctly)

 

I did my mandatory time in med surg. I got tired of it so I deployed and then applied and got accepted to the fellowship

 

You are assuming (you know better) that the wheels are in their current location when the impact force drives them backward, or the cab/axle spatial relationship is constant. They could be straight, or could be turned, or shifted left or right, force could come head on or from the left or right center.

 

Don't you always have assumptions?

Maybe not always, but it's quite common when making calculations as you can't plan for everything.

 

Crash by Mike M, on Flickr

ARB vs late 1990's Grand Prix. Opposing driver clipped a corner and crossed the center line. I was doing approximately 30-35 MPH and stood on the brakes when I saw him cross the center line, so I do not know the ultimate speed of impact on his end, but he was moving.

My air bags did not blow, but I was unhurt. The open gas door was part of the collision, not after the fact. It tore the front axle out of the differential, sheered the LCA in half and completely tweaked the frame.

The opposing car (which I won't post pictures of out of respect of the other driver, PM me if you want to see) had the entire small overlap of the driver's side ripped apart including tearing the full upright out of the car.

His car was deflected under me. I suspect I would have fared much worse had I not had the ARB, but what the calculations say would have happened would have been interesting. I suspect the OEM crash bar would not have taken much of the impact due to where I was hit. I can understand ARB's claim about the bumper protecting the vital pieces of the driveline after seeing my accident.

I did significantly more visible damage to the car that hit me than was done to my truck. I tore the upright right out of their unibody.

Sadly that will be the first piece cut off when Mr. Brodozer feels the needs to run 37s on 20 x 12"s sticking outside the body.

 

We make general assumptions, obviously. For example, if I were designing a handsaw I would assume it is not going to be used as a hammer lol.
But once the handsaw specs for design were complete, there would be no assumptions. The specs would dictate design.

 

Digging this post back up.

Can someone explain why having a greater mass, esp one with low elasticity such as steel bumper, and thus increased momentum, ahead of the passengers would increase likelihood of injury to passengers as well as damage to the said equipped vehicle? Doesn’t that mass behave like a battering ram?

I’m imagining loading up a wheel barrow with rocks and charging into something like, say a refrigerator (stay with me). Then doing the same sans rocks. The wheel barrow is the bumper, the person pushing it is the vehicle, and his elbows, wrists, shoulders are crumple zones. It seems to me that the momentum of the first example would serve to accelerate the mass of the fridge away from the person pushing it thereby offering a substantial decrease in injury and damage to the person pushing it.