Patch-Based Recycled Composites: Experimental Investigation and Modeling Techniques on Four-Point Bending and Curved Beam Traction Tests

Composite materials have experienced a significant increase in demand over the past five decades. This growing usage has led to a considerable production of waste, particularly from prepreg scraps, which can account for up to 35% of the purchased material. This paper explores the recycling of prepreg scraps by cutting them into smaller patches and reassembling them into new sheets. The study follows a dual approach: mechanical testing on two different types of samples is presented, along with numerical modeling strategies designed to capture not only the mechanical behavior of the new recycled material but also the failure modes of the samples. The experimental results demonstrate the feasibility of the proposed technique, with samples made from prepreg scraps retaining 85%, 57%, and 78% of the original flexural modulus, strength, and interlaminar strength, respectively. The numerical models not only fit closely to the experimental data but also successfully predict the failure modes of the new material under the two different loading conditions. The primary highlights of this work lie in (i) its innovative approach to recycling prepreg scraps, which is capable of successfully recovering material otherwise sent to landfill; (ii) an ordinated and easy-to-automate recovery process; and (iii) in the modeling strategies of the new material. The study eventually proposes the development of an "equivalent lamina" made of scrap material that can be used in standard lamination processes to manufacture components with load-bearing capabilities.