Simulation of stone loads in cooperation with Häggblom

Ab A. Häggblom Oy is an engineering workshop from Kokkola. It manufactures high-quality track systems and mining equipment. Its main products are mining buckets and dumper truck bodies. In addition, Häggblom sells wear and spare parts for earth-moving machinery. The company has cooperated with Comatec’s strength calculation team for several years. A central part of the cooperation is developing new methods as part of product development projects.

Caption: The personnel of Ab A. Häggblom Oy fit a pallet on a large truck body manufactured by the company for the mining industry.  Image from an event in the summer of 2019. [/caption]

Comatec’s strength calculation team has been involved in a product development project for a new truck body, which began a couple of years ago. The project involves Häggblom’s new product line for rubber-lined truck bodies. Help was needed with strength calculation to design these customised truck bodies.

“Our aim was to develop a rubber-lined truck body with the customer. From the perspective of strength calculation, these products are challenging, because we have to be able to simulate different kinds of loads like the impact of large stones and loading situations. We also need to simulate how driving affects the structures. We try to optimise the structures and make them as light as possible, while keeping them strong enough to withstand heavy stress in operation.”

“In this project, we were able to develop a well-functioning calculation method that saves calculation time and costs with Comatec. We will use it in the strength analysis of dumper and other truck bodies in future,” says Aleksi Huhtala from Häggblom.

Risto Poutala, Team Leader of the technical calculations team at Comatec, says that the developed calculation method is based on performed tests. The objective was to develop a method where the impact loads from stones could be simulated by using the finite element method.

Häggblom’s previous tests for impact loads provided the basis for the new method. Based on them, it was possible to verify the calculation and consider how rubber, in particular, absorbed the shock. During the project, they also made transient analyses simulating dropping stones.

Long-term cooperation produces new methods and enhances business

According to Aleksi Huhtala, Häggblom has cooperated with Comatec for several years now. Häggblom has two business lines that benefit from Comatec’s expertise. One is the design and manufacture of track systems and undercarriages. The other is mining equipment, which includes the bodies and buckets of large dumper trucks, as well as their optimisation and special design. This category also includes boom systems and special buckets manufactured for dredging customers, as well as special products that require special design work.

“Especially with mining equipment, our work is project-related. We have customised products that require special design work, because we manufacture the products so that they meet the customer’s own requirements. Our strength is our strong design and engineering organisation,” says Aleksi.

“Compared with traditional engineering, we can customise products, implement larger design projects for our customers and take care of all aspects of project management. We ourselves design everything we manufacture. We don’t manufacture many products that have been designed by someone else.

The latest cooperation project with Comatec continues, and we’re developing new methods together all the time. Comatec is interested in trying out different methods, and they have also made suggestions about implementation.”

“Over the last year, we have also experimented with DEM particle simulation with the Comatec team. We found it a good and useful service when developing our products. Comatec has software and simulation expertise.”

“This product development project has enabled us to develop a new kind of business. We have been able to simulate products and start the manufacturing process without having to make so many prototypes. By developing calculation methods, we have been able to start manufacturing even with no prototypes at all. Thanks to the calculation methods, we know better what kind of loads our products can withstand, and the level of optimisation is good. We can offer our customers a service with good simulation and engineering.”

“We’ve been happy with the results so far. Customers have been using the first rubber-lined truck body models for a couple of years now. We can already see whether the simulation corresponds to the reality, because the results are visible in practice. We have received no negative feedback about the calculation methods, in particular.”

“Comatec has strong expertise in simulation and strength calculation, which are not among our core competences. It makes our life easier that Comatec has expert knowledge and the required software, and we can cooperate with them closely,” says Aleksi about their cooperation.

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Technical calculations at Comatec

There are more than ten members in Comatec’s calculation team. They have expertise in different kinds of calculation. Assignments vary from calculation projects of a couple of days to extensive projects of several months. We have made several calculations for different kinds of products over the years. They also provide a good basis for working on new products.