Recife & Campinas, Brazil
Sistemas Termo-fluido-mecânicos Inteligentes
Instituto Federal de Pernambuco · collaboration with Unicamp
With Gustavo Leite, Januário Vieira and Paulo Kurka, we investigate how vehicle mass distribution and suspension affect passenger motion.
IFPE: Gustavo Leite and Januário Vieira.
Unicamp: Paulo Kurka and our SSI Lab team.
Our collaboration
When a car accelerates or brakes, its body tilts and its passengers move with it. Changing where the vehicle’s mass sits changes both motions, sometimes in different directions. Our collaboration with Gustavo Leite and Januário Vieira at IFPE, and Paulo Kurka at Unicamp, combines vehicle dynamics, vibration analysis and computational modelling to understand this interaction. We study the vehicle and passenger as one coupled mechanical system.
We vary mass, centre-of-gravity height and resistance to pitching, then examine how the suspension changes their effects. This helps us distinguish competing mechanisms in combustion-like and battery-electric-like configurations.
We follow the motion from vehicle acceleration and body rotation to an observation point at head height. The frequency and timing of those contributions matter as much as their size.
We connect mechanical modelling with expertise in vibration measurement and signal analysis. Component benchmarks and independent numerical checks help us identify what the model can reliably explain.
IFPE + Unicamp
IFPE · STFMi
Mechanical systems, vibration measurement and signal analysis.
IFPE
Vehicle dynamics and the formulation and review of the mechanical model.
FEM · Unicamp
Multibody dynamics, vibration and vehicle–passenger interaction.
Selected model result · September 2026
In one controlled comparison, the heavier, lower-centre-of-gravity configuration pitches less, yet produces slightly more acceleration at head height. The two measures tell different parts of the story.
Each measure is normalized to its own reference value of 100. Comparison: a 1,600 kg combustion-like reference and a 2,000 kg battery-electric-like case, with suspension rates scaled to axle mass. Passenger acceleration gain uses a flat input spectrum from 0.5 to 2 Hz.
A lower centre of gravity reduces one source of pitching. But changing mass distribution also changes which frequencies the vehicle responds to most strongly.
The passenger receives both forward acceleration and rotation. In this example, the change in inertia shifts the response towards the assigned passenger mode, offsetting the benefit of less body pitch.
Keeping the springs and dampers fixed changes the balance: the heavier case’s passenger gain becomes 2.20% lower. Our ongoing work maps when and why this ordering reverses.
These are preliminary results for constructed model configurations. They describe mechanical motion, rather than measured comfort or the performance of specific production cars.
Work in progress · DINAME 2027
We are preparing Mass distribution and passenger motion: a parametric view of ICE-like and BEV-like vehicles. The study uses response maps and controlled comparisons to explain how mass, centre-of-gravity height, inertia and suspension interact.
The aim is to understand the mechanisms behind passenger motion and the conditions under which a comparison changes.
Josué Labaki, Januário Leal de Moraes Vieira, Gustavo de Novaes Pires Leite and Paulo Roberto Gardel Kurka. Manuscript in preparation; selected result from the September 2026 draft.
