Enhancement of Through-Thickness Thermal Transport in Unidirectional Carbon Fiber Reinforced Plastic Laminates due to the Synergetic Role of Carbon Nanofiber Z-Threads

Abstract

This study experimentally and analytically examined the influence of carbon nanofiber (CNF) z-threads on the through-thickness (i.e., z-direction) thermal conductivity of unidirectional carbon fiber reinforced plastics (CFRPs). It was hypothesized that a network of CNF z-threads within CFRPs would provide a thermally conductive microstructure throughout the sample thickness that would increase the through-thickness thermal conductivity. The experiments showed that the through-thickness thermal conductivity of the CNF z-threaded CFRPs (9.85 W/m-K) was approximately 7.53 times greater than that of the control CFRPs (1.31 W/m-K) and 2.73 times greater than that of the unaligned CNF-modified CFRPs (3.61 W/m-K). Accordingly, the CNF z-threads were found to play a substantial role in increasing the through-thickness thermal conductivity of CFRPs. To better understand the role of the CNF z-threads in through-thickness thermal transport, simple logical models of the CFRPs were constructed and then compared with the experimental results. Through these analyses, it was determined that CNF z-threads substantially enhance the through-thickness thermal conductivity by creating carbon fiber-CNF linkages throughout the CFRP laminate; these linkages allow the heat flow to largely bypass the resistive resin that envelops the carbon fibers. In addition, thermal infrared tests illustrated that the increased through-thickness thermal conductivity of the CNF z-threaded CFRP enabled the location and visualization of defects within the laminate, which was not possible with the control CFRP.

Asymmetrical Damage Aspects Based Investigations on the Disc Brake of Long-Range UAVs through Verified Computational Coupled Approaches

“…The ANSYS transient thermal tool is the computational platform integral to achieving thermal outcomes such as heat production owing to friction and, by extension, thermal stress induction. Computational evaluations rely heavily on material parameters including thermal conductivity, thermal coefficient, and thermal diffusivity; to obtain these values, researchers have combed through the literature [2,[6][7][8][9][10][11][12][13]. UAV disc brake heat production…”

“…For this reason, the thermal outcome is best calculated analytically and computationally with the aid of typical boundary conditions and beginning variables such as thermal conductivity, thermal diffusivity, and specific heat capacity. All of these basic thermal parameters for the imposed lightweight materials are culled from widely available literature reviews, wherein references to articles [6][7][8][9] on the required thermal characteristics of carbon fiber-reinforced polymer (CFRP) were made. We cited [10] for information on the thermal properties of glass fiber-reinforced polymer (GFRP), and [11,12] for information on the thermal characteristics of kevlar fiber-reinforced polymer (KFRP).…”

“…With more concern, the fineness ratio (FR) of the fuselage was fixed as 10. The major and minor fineness ratios are mentioned in Equations ( 6) and (7), respectively [3,4,15,17].…”

Thermal conductivity and mechanical properties enhancement of CF/PPBESK thermoplastic composites by introducing graphene

“…In pure CF/PPBESK, the number of surface-active groups on the fiber is small, which makes the weak interfacial adhesion between the fiber and the matrix, and has different degrees of defects. [39][40][41][42] Cracks causes by stress concentration in defects under load will rapidly expand along the interface, and eventually lead to catastrophic failure of the interface. [3] When graphene is introduced, the rough surface of graphene increases its mechanical interlocking ability with resin and promotes stress transfer between composite layers.…”

Carbon Nanofiber Z-Threaded Carbon Fiber Reinforced Polymer Composite (ZT-CFRP) Laminate Parts Produced Using a Magnetic Compaction Force Assisted Additive Manufacturing (MCFA-AM) Technique

“…The estimated magnetic compaction pressure of 0.21 MPa was used for consolidation during printing and the compaction pressure significantly reduces the size and content of voids despite no vacuum being applied during MCFA-AM process [19]. Previous studies have shown that by using carbon nanofibers (CNFs) z-threads in CFRP laminates, mechanical properties (e.g., Mode-I interlaminar fracture toughness [12], interlaminar shear strength (ILSS) [13], and longitudinal compressive strength [14]), thermal properties (e.g., through-thickness thermal conductivity [15]) and electrical properties (e.g., through-thickness DC electrical conductivity [16][17][18]) can be significantly improved even when using low CNF concentrations (0.3 wt% to 2.0 wt%). This paper employs a radial flow alignment technique (RFA) [20] to make CNF z-threaded CFRP prepreg tape, thus produced prepreg tape is used by MCFA-AM to print parts.…”