Broken Frame on a RAM 3500
You may have seen pics of this truck and camper floating around the interwbez for the last few weeks. Here's an article about it that was published earlier today. Broken Frame on a RAM 3500
Forum Discussion
Regardless of the well discussed issues here the frame failure was most likely due to fatigue. Fatigue is caused in steel by REPEATED stressing over 50% of bend strength and release. Flexing over bumps can cause a lot of stress and release situations.
40 years ago many of the truck campers I saw had shock absorbers on the front of the cabover going down to the front fenders. The point of these was to absorb the frame damaging stresses that lead to fatigue and also control a bouncy ride. I ran a rig for 20 years that was probably more overloaded than the one here. It was 19'6" overall with the cabover hanging out so far over the Supercab that it hit the radio antenna. It had a lot of frame flex that I felt had to be dealt with. I didn't like the shocks but I found some fairly still but flexible foam and built a cushion to go between the cab and the cabover just behind the windshield and full width. That extra leverage on the frame did a lot to reduce the flexing and improve the ride. Also, my truck never broke in half. Just a thought for people with long and heavy campers.
If the frame was cut or welded to without smoothing the transition areas of focused stress that can lead to increased fatigue and early failures. For example, if a bracket is welded to the frame in a way that leaves a sudden step it will likely fail at the edge of that step weld bead. The step needs to be extended and ground to a smooth transition. Also, many frames are heat treated and can be locally annealed by welding and that can also lead to stress failures.
Modern frames are designed to be light and strong which means that stresses are spread evenly throughout the metal. If you mess with the way those stresses are spread disaster can result.
40 years ago many of the truck campers I saw had shock absorbers on the front of the cabover going down to the front fenders. The point of these was to absorb the frame damaging stresses that lead to fatigue and also control a bouncy ride. I ran a rig for 20 years that was probably more overloaded than the one here. It was 19'6" overall with the cabover hanging out so far over the Supercab that it hit the radio antenna. It had a lot of frame flex that I felt had to be dealt with. I didn't like the shocks but I found some fairly still but flexible foam and built a cushion to go between the cab and the cabover just behind the windshield and full width. That extra leverage on the frame did a lot to reduce the flexing and improve the ride. Also, my truck never broke in half. Just a thought for people with long and heavy campers.
If the frame was cut or welded to without smoothing the transition areas of focused stress that can lead to increased fatigue and early failures. For example, if a bracket is welded to the frame in a way that leaves a sudden step it will likely fail at the edge of that step weld bead. The step needs to be extended and ground to a smooth transition. Also, many frames are heat treated and can be locally annealed by welding and that can also lead to stress failures.
Modern frames are designed to be light and strong which means that stresses are spread evenly throughout the metal. If you mess with the way those stresses are spread disaster can result.
