Employing Simulation-Driven Solutions to Develop an Iconic Sculpture

New Zealand lore tells of the great navigator Ngatoroirangi, a Māori high priest who originally hailed from Hawaii. While exploring New Zealand, he became stuck in a snow blizzard atop Mount Tongariro. Desperate for help, he called out to his family in Hawaii to send him warmth and fire. They answered his call in the form of the geothermal hot springs we can observe in and around the region today.

The town of Rotorua is a popular tourist destination, renowned for its geothermal activity and Māori culture. In the Whakarewarewa Valley, the 30 meter-tall Pohutu Geyser erupts many times daily. The erupting water and steam of the geyser, along with the harrowing story of Ngatoroirangi, served as inspiration for the curved structure of the gateway sculpture design by Stacy Gordine from the New Zealand Māori Arts and Crafts Institute.

The local council of Rotorua, New Zealand approved upgrades to the town’s road network, including a large roundabout at the Southern border. This presented Rotorua with the unique opportunity to create a showcase art installation to serve as a gateway, welcoming visitors and residents into the town.

To help realize this ambitious project, the town elicited the help of global composites company, Gurit.

Based in Wattwil, Switzerland, Gurit is a developer and innovator in the composites industry as well as the leading global supplier of composite materials, engineering services, tooling equipment, and select parts and systems. Gurit has over 30 years’ experience in the practical application of composites across various market sectors and projects, from small parts to large-scale structures, combined with a unique technical approach which enables them to offer a complete set of composite solution.

Gurit is present throughout the advanced composite value chain, from upstream structural engineering, to materials, processes, and testing, and downstream, delivering prototypes and fully finished manufactured parts.

Overcoming Environmental Challenges with Advanced Engineering

The Te Ahi Tupua sculpture measures about 12 meters tall with a diameter around 6 meters. The inner and outer spirals are made up of groups of tubes with interconnected chevron plates. Four panels featuring traditional carvings are inlaid into the gaps within the sculpture. Initially, this was designed using steel, however concerns at the manufacturing stage lead to a reassessment of the materials to be used. The highly corrosive environment of Rotorua due to the geothermal activity presented potential issues with the longevity of the piece.

“It was interesting to see traditional Maori carving features represented using the modern technologies of 3D printing and composite materials,” said James Ledingham, Composite Structural Design Engineer at Gurit. “This created some unique challenges at the connections between parts which required careful analysis and verification via physical testing to produce a design that was both structurally sound and true to the artistic intent of the sculpture.”

The organic nature and complex curvature of the structure suits the layered nature and drapability of composites materials. Traditionally, costs associated with the molds and tooling needed to construct composite structures would be prohibitive, but the advent of additive manufacturing has enabled their use in many more architectural applications.

Around a thousand interlocking pieces were 3D printed and assembled, then wrapped in woven carbon fiber to form the curved tube structure. Gurit joined the project to confirm material quantities and verify that the required composite strength was achievable in order to withstand applied structural loads including the effects of high wind and earthquakes.

Leveraging Simulation to Validate Structural Integrity and Minimize Cost

A simulation-based solution was imperative since much of the stiffness is generated by the sculpture’s interconnected nature, resulting in very complex load paths. Using Altair HyperWorks software, Gurit was able to model and accurately interpret the bending stresses to derive the stiffness of the structure. A laminate optimization was then run with the objective to minimize mass. The Altair software weighed cost criteria and maximum deflection factors to help Gurit arrive at the optimal project result; a laminate structure that meets strength requirements, minimizes mass and cost, and maintains a simple, easy to build design.

Features like the auto-meshing and composite fiber orientation mapping in Altair® HyperMesh® allowed Gurit to quickly and accurately model the geometry and simulate the loads and stresses on the structure.

Now in the final stages of manufacturing, all involved in the project are excited for the Te Ahi Tupua sculpture to take its place at the gateway of the town. Incorporating New Zealand’s cultural history, unique geography, and technical innovation, the sculpture stands to embody the absolute best of Rotorua, past, present, and future.

Artist, Sculpture Designer
Stacy Gordine

Manufacturer Specialist
Kilwell Fibretube

Engineering
Gurit

About Gurit

Over 30 years experience in the practical application of composites across various market sectors, combined with an impressive portfolio of materials and a unique technical approach, enables Gurit to offer the most complete composite solution on the market.