Experimental investigation of the low velocity impact behavior and residual compressive strength of a novel Double–Double layup composite laminates

Abstract Double–Double (DD) laminates, a novel composite layup design, have attracted much attention due to its flexible stacking sequence of [±Φ/±Ψ] rT and greater design flexibility. DD laminates exhibited advantages in industrial applications by simplifying stacking design, reducing weight, and enhancing manufacturing efficiency. However, the research on the impact resistance of DD laminates is still limited. Thus, this paper focused on the impact resistance and compressive properties after impact of DD laminates. In this study, four controlled trials composed of the DD laminates and its converted legacy quad laminates (LQL) were designed. Then, low velocity impact (LVI) tests and compression after impact (CAI) tests were carried out to obtain impact response curves, while ultrasonic C‐scan was applied to conduct damage evaluation. DD laminates showed remarkable advantages over LQL laminates in impact resistance. The residual compressive strength (RCS) of DD converted from QI and Hard increased by 4.36%–28.99%. The maximum reduction of delamination damage projection area (DDPA) for the impacted DD was up to 63.02% compared to that of LQL. It was particularly noteworthy that flipped DD exhibited significant differences in impact resistance, which differed from the LQL ones. Highlights The research on impact resistance of LQL and DD laminates was expanded. DD laminates reduced the DDPA after LVI. The dent depth of DD converted from Soft and Hard1 types decreased. The front and reverse impacts of DD laminates were compared. DD converted from QI and Hard could improve the RCS.