The goal of this thesis project was to explore how material originating from thermoplastic composite wind turbine blades (TPC WTB) can be reshaped. The insights gained during exploratory activities were used to design a re-use application. The demonstrator model should inspire people to develop other applications and build upon the foundations laid here.
While wind turbines are a big contribution to the green energy supply, their blades form a problematic waste stream of hard to recycle material. One upcoming blade design innovation aimed at enhancing recycling, that of thermoplastic composites, has opened up a new opportunity in circular end of life strategies: structural re-use through reshaping.
A reference TPC blade was drafted based on insights gained from literature and experts, which defines characteristics like material composition, structure and curvature. These were needed for subsequent material tinkering activities aimed at understanding the material, exploring forming limits and process parameters (Figure 1).
 
These findings, together with material properties and opportunities and threats were combined in a SWOT matrix and design requirements. Blade segmentation was used to make a panel classification table which contains information on panel characteristics which were later used in designing an application. To be able to shape smaller radii, it was decided to split the top layers from the sandwich panel which resulted in much thinner laminates but also more unused material (15 wt%).
After a solid understanding of the material was built, an application could be designed. Standard ideation tools like brainstorming were used but also less standard methods aimed at finding applications yielded diverse application ideas. Following the design vision, one idea was selected: a lamppost. Embodiment of the lamppost based on earlier findings and a norm resulted in a conceptual application design. To prove the feasibility of this application, the strength and stiffness of the post were calculated to comply with the NEN EN 40 norm.
This design was translated to a demonstrator which can be seen in Figure 2. The goal of this demonstrator was to evaluate the performance of the material in reshaping and to simultaneously inspire people to develop new applications, which was validated using interviews. An evaluation of the amount of material used in this application showed that about a third of the yearly supply of WTB material saturates the yearly demand of lamppost.
It can be concluded that the material performs well in reshaping single curved geometries, however reshaping could be problematic for double curved surfaces. The smallest single curved radius tested was 30mm while the largest double curved radius which was tested was 1000mm. A meaningful application which makes use of the material’s value can be made within the reshaping limits while also utilizing a significant amount of blade waste.

The current vision of Microcab is to increase the repair capabilities of the VIANOVA. Part of that vision is to begin the shift towards a circular economy in which the lifecycle of the product is extended, and parts can be processed in a circular manner during the lifecycle. Considering that Microcab is a small company and the challenge is considerable, additional safety regulations mean that a vehicle should become a road-safe vehicle. This graduation project contributes to this challenge by researching the main question that focusses on the front section of the vehicle: ‘How can Microcab design the front section of the VIANOVA to increase the repairability and solve the safety issues?’. Through several analyses and explorative design directions, the result is a concept that reconfigures the front section of the VIANOVA to allow for increased repairability and better safety requirements while maintaining the goal of becoming more circular. An important requirement is that the concept should allow for a production volume of 500 units annually. The current design of the front clip is a single large body panel hand-made from a glass fibre reinforced thermoset, which is difficult to repurpose and recycle. Based on research data, a sustainable alternative known as thermoplastic olefin (TPO) is introduced. Furthermore, the front clip has been split into four segments. These changes allow for better repair capabilities and lower the overall impact of a low-speed collision. In order to make this possible, structures were required to support the panels and increase energy absorption. The bonnet with incorporated headlights is enlarged to increase accessibility during service and fixated on the support structure, removing it from the impact zone. The support was required to improve safety for pedestrians and increase protection of internal components. This support consists of adding an energy absorber, upper load beams, cross member, and extending the width of the bumper beam. Additionally, it is recommended to use plastic fasteners to increase circular capabilities, considering that these are more likely to break, allowing for the body panels to remain intact. Lastly, it is recommended to implement a different type of surface finish. 3M provides an PVC-free wrap material, reducing the use of harmful chemicals and increasing repairability and circularity. This change also provides opportunities to illustrate internals or implement advertisement. Therefore, the project reveals that there are multiple elements that can have a positive influence on the repairability and safety issues while at the same time, shift towards a circular economy. The recommendations that emerged from the project provide a high desirability, but will require follow-up research am physical crash testing to determine optimal configuration of the front section, and create a better understanding of the elements and how they influence impact resistance and repairability.

The circular composites design guide presents circular economy strategies, product design aspects and tools to (re-)design products containing composite materials for a circular economy. A circular economy closes the loop for products, parts and materials, through reuse and recycling. In this guide you will find 5 circular economy strategies, 26 design aspects and 3 design tools specifically aimed at composite products. All have concise descriptions and inspirational examples developed in project Ecobulk and at Delft University of Technology.@en

With the emerging demand for energy-efficient products, the composite material has become a point of attraction for many product manufacturers. Furthermore, with its high strength to weight ratio, long life span, low maintenance and design flexibility, composite materials offer tailored properties by choosing an appropriate combination of reinforcement and matrix material. Being one of the leading users of composite material, the Netherlands is a global player in the field of design, automation, material development and sustainability in the field of high-grade-reinforced plastic.

Recycling of the decommissioned composite material remains underdeveloped research. The current shredding and inefficient recycling result in the loss of material property, struggling to find its scalable application in the market. However, the composite material has a longer life than its entire product, resulting in premature decommissioning of the material due to constant development in the product design. One way around this problem is repurposing. Therefore, there is a need to look for an alternative approach.

Repurposing aims to keep the material alive by utilising its shape and remaining potential in serving an additional product life with a different application. However, the concept of repurposing is undiscovered in the field of composite material.

This graduation thesis aims to create a set of guidelines for industrial designers and companies, guiding them to efficiently utilise the composite material’s value with the practice of scalable repurposing.

Further to industrialise and streamline the repurposing practice, there is a need for product lifecycle management, assisting repurposing industrial designers and companies with the set of prerequisite information.

By case study of repurposing an aircraft galley made from the glass fibre reinforced plastic into a bicycle cart for kids, various operations, including disassembly, dismantling and re-manufacturing, were executed to gain a closer look into the repurposing. In addition, different stakeholders’ roles in repurposing were identified by conducting interviews with various actors involved in the composite industry. With the help of the theoretical and practical insights gathered during the exploratory phase, the PLM framework and guidelines were formulated focusing on scalable repurposing of the composite material.

A revised set of guidelines was proposed by evaluating the draft guidelines through an interview with the repurposing company and a co-creation session involving various stakeholders, education experts and industrial designers. Based on the evaluation, it can be concluded that the guidelines can serve as a base for implementing the repurposing practice, where the industrial designer can connect the detached stakeholder and guide the implementation of composite repurposing.

However, to make these guidelines well qualified for all the composite products from different sectors, a wide range of case studies should be conducted. Although these guidelines are formulated to support industrial designers to impact repurposing positively, further work is needed to conduct a business model, real case scenario, and policy management to look into the guidelines’ pertinency.

Within this project a design approach of 3 phases is created to guide designers in the redesign of an existing product for Repurpose: 1.Starting point: To find certain opportunities in the future by highlighting essential valuable aspects of the current product that could be maintained in future products. 2.Product Opportunity: The Designer is guided from evolved ‘valuable aspects’ towards 1 chosen product opportunity, by which the current product can be Repurposed. ‘Search Areas’:This phase aims to inspire how value of a current product can be extended towards the future. 3.Design for Change: Redesign product and parts for efficient and effective transition into the subsequent use-cycle.

In this report, an overview of the most common recycling methods for composite materials is created. It describes the process and recyclate characteristics, as well as the (dis)advantages of each method and the environmental and technological development. To draw conclusions on the current feasibility of composite recycling, the gathered data is analysed on the subject of application, quality, economy and sustainability. The report ends with a future outlook, and what implications this might have.

The wind energy industry is growing significantly, which increases the number of decommissioned wind turbines as well. The blades of wind turbines are mainly made of fiber reinforced thermoset polymer composite, which is difficult to recycle. Most blades currently end up in landfill or incineration which is a waste of this high value material. In this project, a valuable application for mechanically recycled composite material is designed, which will ensure the wind turbine blades of an end-of-life situation that fits within the circular economy. Material research is executed to get a grip on the characteristics of the shredded composite. These specific characteristics are eventually used to generate ideas on valuable applications for the material in which the recyclate is a wanted addition, instead of a disturbance. Based on the formulated vision, requirements and wishes, an electrical car charger is selected as the best suitable idea. This product demonstrates how the shreds can be reused in a thermoplastic material. It has a symbolic link with the wind energy industry and anticipates on the energy suppliers, who own the wind turbines, by recycling the material into a product they offer.
The electrical charger is produced by pressing the shredded composite between two sheets of thermoplastic material and shaping this with vacuum forming. After its use, the product can be again recycled into new applications. However, the shredded composite will be part of a cascading model in which the fiber size will decrease with every recycling procedure. The design is only reusing a small amount of the total supply of composite waste and is therefore not an all-encompassing solution to the problem. Additionally, mechanical recycling does cause significant down-cycling of the high value material. Therefore, it is best to replace the thermoset polymer composites with a better recyclable material, until a recycling procedure turning the fibers and resin back into raw materials is fully developed.