Background:
Plate compactors are used to flatten the ground to obtain a certain grade of uniformity and hardness. The ground could be soil , asphalt or gravel , and there are different compactors for different applications. The b ottom plate , also referred to as the base plate , is the main source of vibrations and is also the primary focus when it comes to plate compactors. The mass distribution and excitation force play important role s for the vibration and performance capabilities of the machine. So , if there is a change in the mass distribution and the location of the excitation force, the movement of the bottom plate will be affected which in turn affects the maneuverability of the machine. T o interpret and improve the performance of the compactor , it is essential to know how the machine is affected by change s in different parameters of the compactor . Although Finite Element (FE) modelling gives an accurate estimation, it is computationally expensive and time consuming to run simulations for different design ideas. Therefore, it has been decided that a simple mathematical model , similar to a spring - mass system , should be developed that can help to understand the bottom - plate dynamics and allow for a better way to initially filter out different design ideas of the bottom plate. If the model yields accurate results, they can also be used in the FE m odelling.

Goal: To build a mathematical model of the compactor in a similar manner to a spring-mass system , and to simulate and animate the behavior of the compactor during its operating conditions.

Task s :

• Develop e quations of motion for the system that yield acceleration, velocity, and displacement.

• F ormulate t he rubber dampers as linear springs with damping and stiffness in 3 dimensions .

• Describe the b ottom plate movement in a 3 - dimensional domain to virtually identify irregularities.

• F ormulate the mathematical model so it is applicable to both forward and reversible plates.

Further scope : If the model is completed early and verified with the physical model, then the possibilities of developing a mathematical model of the next level of de-vibration should be explored.

• I n the first de-vibration impleme ntation, the mass of all other components can be treated as a point mass located at its COG , w hich should be possible to extract from the machine's accelerations and displacements .

• A s imilar model of the rammer could be built as well , where modelling of the de-vibration is straight forward .

Who can apply: Applicants should have a good understanding of vibration theory and rigid body dynamics , with an interest and some knowledge in P ython programming.

Contact:

Petri Piiroinen
Associate Professor in Nonlinear Mechanics
M2, Chalmers University of Technology
Email: petri.piiroinen@chalmers.se

Karl Elmestrand
R&D Mana ger

Husqvarna Construction Products
Email: karl.elmestrand@husqvarnagroup.com

Nikhil Nandigama
CAE Engineer
Husqvarna Construction Products
Email: Nikhil.Nandigama@husqvarnagroup.com

References:

Husqvarna Construction Products