Husqvarna Group is a global leading producer of outdoor power products and innovative solutions for forest, park and garden care. Products include chainsaws, trimmers, robotic lawn mowers and ride-on lawn mowers.
The Group is also the European leader in garden watering products and a global leader in cutting equipment and diamond tools for the construction and stone industries. The Group’s products and solutions are sold under brands including Husqvarna, Gardena, McCulloch, Poulan Pro, Weed Eater, Flymo, Zenoah and Diamant Boart via dealers and retailers to consumers and professionals in more than 100 countries. Net sales in 2017 amounted to SEK 39bn and the Group has around 13,000 employees in 40 countries.
Low speed impact simulation of robotic lawn-mower
To increase level of confidence in our simulations we need to improve the material modelling. Robotic lawnmowers are subjected to repeated loading by impacting objects. The material properties of the plastic parts depend on the loading rate and the aim is to use existing material testing capabilities to develop visco-elastic material models.
Develop a method to convert dynamic mechanical analysis (DMA) results to visco-elastic material models in LS-Dyna.
The work will also include correlations against physical impact tests and an investigation of different modelling techniques.
There is also a wish to evaluate the fatigue life of both glass-fiber filled and unfilled plastics.
Proper area of education: Mechanical Engineering
The thesis will include:
Literature study and investigation of existing work in this field.
The students will work together with the materials and simulation department to find a suitable method for transferring material test results to a LS-Dyna material card.
Step 1: Generate visco-elastic material model from DMA measurement (Dynamic Mechanical Analysis). Instead of a constant E-modulus we will use a modulus that depends on loading rate.
Step 2: Build complete model. Correlate impact force curve.
Step 3: Plan and perform fatigue testing.
Step 4:´Make fatigue calculation. Investigate if Digimat can be used for glass-fiber filled materials.
Reporting will be through regular meetings and written documentation in the form of a "Husqvarna design guideline" as well as the wishes of the University.
Mikael Ganhammar, CAD/CAE/PDM Manager (firstname.lastname@example.org)
Mikael Palm, Structural Analysis Specialist (email@example.com)
Last day of application:
Content checked / updated 2017-06-09