The upgraded Ferrostar: stronger sidewalls, lighter front bulkhead and lower step frame chassis
At STAS, we’re always looking for ways to improve our semi-trailers and make them more sustainable. Our steel Ferrostar tipping trailer is specifically designed to be a sturdy and reliable tipper for transporting heavy scrap. We recently redesigned it to further optimize and increase its life cycle and make the Ferrostar even stronger and safer.
One of the key tools we used to make this possible is the finite element method (FEM). It’s a computer simulation technique from the aerospace industry that allows our engineers to predict how materials will deform under pressure. We could visualise the stresses and deformations in the Ferrostar’s body and chassis during loading, tipping, and unloading, and to adjust the design accordingly. As a result of the FEM analysis, we were able to strengthen the Ferrostar’s sidewalls, make the front bulkhead lighter and stronger and lower the step chassis.
Sidewalls
During the redesign, we deliberately paid attention to reducing the amount of stress on the sidewalls. We wanted to redistribute the stress and discovered that by eliminating a few reinforcement elements and their welding, the tension on the sidewall could be redistributed on the entire side wall. Hardox is made to be flexible, so we allowed a little bit of elastic deformation on the sidewalls. This means the sidewalls slightly flex but always return to their original shape after unloading. This extra flexibility means that forces are distributed across the entire sidewall, rather than concentrated on the reinforcements themselves.
Due to the higher forces caused by the load in combination with the extremely large side wall height and length, we have decided not to use the new version on our Ferrostar 86 m³.
In the previous version, we can see that there’s less stress on the sidewall plates themselves, but the stress is highly concentrated on the welded areas around the reinforcements (red area). This means there’s a higher risk of fractures on the welding. In the new and improved version, the stress is directed towards the sidewall plates, which results in lower peak stresses on the reinforcements and a longer lifetime of the body.
Front bulkhead
The front bulkhead has been made 10% lighter without compromising on its strength. The redesign also redistributes the tension across the entire front bulkhead making the Ferrostar more durable than ever! We ended up making the front bulkhead twice as strong while following the Eurocodes.
In the previous version, the stresses from pushing the trailer body up are concentrated right above the cylinder mounting point and the top edge experiences deformation from the tipping procedure which has an impact on stability. In the new version, the stress is better distributed towards the stiffest areas of the body: the upper rail and the bottom corner profiles without deforming them. This has a positive impact on stability and of course safety.
Chassis
The Ferrostar is equipped with a step frame chassis, which means the chassis is lowered from the landing legs to the tail end and has the advantage that it slightly lowers the centre of gravity of the loaded tipper. We lowered the step in the frame chassis another 10mm, which further increased the stability of the tipping trailer, reducing the risk of a tipping accident and making it safer to work with the upgraded Ferrostar. This also allows for a higher volume of cargo, especially convenient when transporting light scrap materials.
Weight of the new Ferrostar
We improved the Ferrostar’s sidewalls, front bulkhead and chassis without adding any weight. We reduced the weight of the front bulkhead and sidewalls and added material to the chassis to extend its lifespan. These changes make the Ferrostar more sustainable, stronger and safer. We’ve thoroughly tested the new model, and we’re confident that it makes bulk transport a long-term pleasure.
Interested in the improved Ferrostar? Contact your nearest and dearest STAS dealer:
