## 2 Literature Review
### Sustainable Product Design Materials Feature Extraction  
The application of sustainable materials can directly influence the sustainability of products. This study primarily examines the impact of sustainable design on product design, with a particular focus on the role of sustainable materials. The hardness, density, and strength of sustainable materials are crucial parameters in product design, exerting a profound influence on the performance, lifespan, cost, and user experience of products. The impact of material hardness on products can be observed in four key areas: product touch and comfort, wear resistance and durability, structural stability, and processing difficulty. With regard to product touch and comfort, hardness has a direct impact on the tactile experience of the product. For instance, the hardness of a key can influence the user's operating comfort and perception of the product. In terms of wear resistance and durability, products with higher hardness have a more wear-resistant surface and are suitable for applications that require long-term friction or impact, such as mechanical parts and tools. The impact of structural stability on the product is reflected in the high hardness of the material, which tends to have better structural stability. This helps to maintain the shape and dimensional accuracy of the product. Concurrently, the hardness of the material and the difficulty of processing will influence the cost of the product. The necessity of higher cutting and grinding forces during the processing of harder materials may result in increased difficulty and higher costs. The impact of material density on the product is primarily manifested in the weight, volume, and quality of the product, as well as the associated cost and resource consumption. The most immediately apparent impact of material density on the product is reflected in the weight. Density directly affects the weight of the product, which, in turn, affects the handling, installation, and use of the product. In instances where a lightweight design is required, the selection of a less dense material can assist in reducing the weight of the product. Furthermore, material density affects the volume-mass relationship of a product. For a given volume, the greater the density of the material, the greater the mass, which affects the stability and load-carrying capacity of the product. Finally, and most central to the concept of sustainable design, is the issue of cost and resource consumption. The production of a given volume of a product from a denser material will require a greater quantity of raw materials, which can result in higher costs and increased resource consumption. The impact of material strength on products can be observed in three distinct areas: load-bearing capacity, safety and reliability, and structural design. Among these factors, the load-bearing capacity is reflected in the high strength of the material. Products with greater load-bearing capacity can withstand greater loads and impacts. This is applicable to the need to withstand heavy loads or high-impact occurrences, such as building structures, automotive parts, and so on. In terms of safety and reliability, products with high material strength are less susceptible to damage or failure when subjected to external forces, which enhances the safety and reliability of the product. In the product design process, the appropriate strength index is selected according to the intended use of the product and the load requirements. This is then reflected in the corresponding structural design, ensuring that the strength of the product meets the required specifications. In conclusion, the parameters of hardness, ductility, density, and strength occupy a pivotal position in the product design process. In the context of product design, it is essential to consider the impact of these parameters in a comprehensive manner, with a view to selecting and optimizing them in a manner that is aligned with the specific needs of the product in question.