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Honda R&D Americas is justifiably proud of its body-structure engineering, displaying a cutaway and color-coded body of its all-new 2019 Acura RDX at the 2018 SAE WCX. The door ring system is shown in red. (Honda)

Acura and ArcelorMittal debut world-first hot-stamped door ring system on 2019 RDX

The 2019 Acura RDX will feature the world’s-first hot-stamped inner/outer front door-ring system. The tailor-welded components are part of an all-new body architecture developed by Honda for the third-generation of Acura’s mid-size SUV. The new structure provides a 50% increase in the use of high-strength materials, increasing rigidity while dropping body-in-white weight 19 kg (42 lb), according to body development lead engineer Joe Riggsby.

Acura debuted the new door ring system at the 2018 SAE WCX in Detroit, with the tailored blanks from supplier ArcelorMittal on display at an adjacent booth. The new door-ring system is helping Acura reach significant crash-performance and stiffness goals for a platform anchoring a new five-link rear suspension, and the fourth generation of Acura’s torque-vectoring Super Handling all-wheel-drive.

The new ultra-high-strength (1,600 MPa) steel front door-ring system is an evolution of the single (outer) ring technology that debuted on the 2014 Acura MDX. A laser-welded tailored blank permits thickness optimization around the ring, maximizing chassis performance and material utilization.

The outer ring on the 2014 MDX used two sections of differing gauge. For the 2019 RDX, both the inner- and outer-rings use ultra-high-strength tailor-welded blanks. The outer ring is composed of four sections in three gauges, with the inner ring composed of five sections in two gauges.

The new inner ring also incorporates the inner sill, providing improved connection to the floor and roof structures. This is part of a new inner-set manufacturing process for the RDX, which makes the use of an inner ring possible. Inner-set manufacturing first welds front and rear inner door rings to the floor, then adds the roof rail, rear rail and windshield lower before the chassis’ outer structure is applied.

“We’ve evolved the technology from the 2014 MDX, and it’s about balance,” Riggsby told Automotive Engineering. “Now part of system, the inner and outer rings can be further optimized for weight reductions and performance gains.”

The new door-ring system contributes to increased body rigidity and fitting-point stiffness on a chassis with a 2.6-in (66-mm) longer wheelbase, and also featuring a standard panoramic sunroof without crossmembers.


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