New tipper trailer design wins international prize

A ground-breaking tipper trailer, guaranteeing maximum payload; fuel efficiency; and extreme durability, has been developed.

By implementing design advances in the use of high-strength steel, the weight of the tipper trailer was significantly reduced. The new design won the international Swedish Steel Prize 2018.

Italian original equipment manufacturer Mantella, redesigned its Stratosphere tipper trailer using materials developed and produced by Nordic steel manufacturer SSAB.

Using SSAB’s abrasion-resistant Hardox 500 Tuf in the body and Strenx 960 in the chassis, led to a combined weight reduction of 510 kg and a resultant increased payload of 510 kg.

The Hardox 500 Tuf wear plate, with higher wear resistance; increased hardness; toughness; dent- and crack-resistance, allows for a reduction in plate thickness of 1 mm, saving on average 365 kg in body weight. The material has a narrow hardness window of 475-505 Brinell hardness number (HBW) and its relative wear-life can be 30-50% longer than other materials. It has a guaranteed impact-toughness of 27 J at -20 °C and, for a 20 mm plate, an average value of 45 J at -40 °C

When using a thinner material, the design must ensure the stiffness and overall stability of the trailer tipper body. Raising a fully loaded body with a front-mounted hydraulic cylinder puts the tipper body under high stresses and, if not designed correctly, this could result in a sudden buckling of the sides.

A number of design changes were made, such as adding horizontal bends to the side panels, to counteract this. The hydraulic cylinder attachment, top rails, rear frame, and tipping pivots were also redesigned for added torsional stiffness.

In addition, Mantella produced the longitudinal beams of the chassis by bending a single, flat strip of Strenx 960. Instead of making a traditional I-beam by welding flanges and web together, the company used press bending to produce a Z-shaped form without welding.

Tipper trailers often operate off-road, under demanding conditions, with a variety of heavy and unpredictable load-cases, leading to equipment-fatigue. Eliminating the welded I-beams and leaving the flanges untouched by welds, increases the chassis’ fatigue-strength.

The new trailer chassis in the Stratosphere series is similar in weight to aluminium, with the durability, fatigue-strength and production advantages of steel. The Z-beams take about 50% less time to produce, compared to welded I-beams. In addition, lateral stiffness is increased by 10% and torsional stiffness by 12%.

The company offers a chassis that is 145 kg lighter and promises superior mechanical properties and improved road handling.

In addition, the stronger and lighter semitrailers contribute to saving fuel and reducing CO2 emissions, with a potential saving of 12 000 l of fuel and 30 t of CO2 over 12 years of service.