Fracture toughness micromechanics by energy methods with a photocure fiber‐reinforced composite

Abstract

A fracture toughness analysis for discontinuous fiber reinforcement was evaluated as a function of fiber volume percent (V f ) using advanced flexural bend tests. Fully articulated fixtures with 40-mm spans were used to examine specimens (2 × 2 × 50 mm 3 ) under conditions of Euler-type bending to reduce shearing effects. Testing for fracture toughness in standardized international units (kJ/m 2 ) using fundamental mechanics-of-materials energy methods by strain energy was then applied for assessment of resilience and work of fracture (WOF). Fracture toughness was also measured as strain energy release (SER IC ) for the condition of unstable fracture between peak load and 5% maximum deflection past peak load. Energies were calculated by numerical integration using the trapezoidal rule from the area under the load-deflection curve. Fracture depths were normalized using sample dimensions from microscopy imaging for a combined correlation matrix analysis of all mechanical test data. V f significantly correlated with resilience, WOF, and SER IC , but negatively correlated with degree of crack depth with p < 0.0000005. All measured interrelated properties also significantly correlated with one another (p < 0.000001). Significant fracture toughness differences between particulate-filled and fiber-reinforced composites began when adding fiber reinforcement at 10.3 V f for resilience, 5.4 V f for WOF, and 5.4 V f for SER IC (p < 0.05).

Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

“…Alternatively, by the same electrochemical concentration gradient effect electrons could be effectively donated to reduce fracture or grow tissue such as the fiber cuff stimulated by fiber fragments in Figures 2(e) and 2(f). In addition to surgically induced inflammation from tissue-cell damage, during cellular energy synthesis excess free radicals subsequently further occur during hypoxic metabolic respiration when oxygen is absent [15-17] which is the common state at the implant interface. Without the final oxygen electron acceptor, metabolic acid cannot combine to form the normal physiologic waste product as water [15-17].…”

“…In addition, polarized inorganic fillers similar to bone mineral are commonly included in thermoset free-radical cure bisphenyl polymers to improve mechanical/physical properties and control manufacturing process consolidation [2, 13, 14]. Eukaryote mammalian cells then extensively require inorganic calcium and phosphates derived from a large bone source to insulate and seal lipid membrane compartments and establish voltage potentials [15-17]. With a negative membrane potential, cells then have the ability to do work and develop [15-17].…”

“…Eukaryote mammalian cells then extensively require inorganic calcium and phosphates derived from a large bone source to insulate and seal lipid membrane compartments and establish voltage potentials [15-17]. With a negative membrane potential, cells then have the ability to do work and develop [15-17]. …”

“…Bisphenyl-polymer/carbon-fiber composite electrical-conduction/resistivity properties [9, 17-19] are similar to bone [9, 17] with design capability to better simulate conditions favorable to the approximate −70 mV plasma cell membrane resting potential [16, 17] and complex electron-transfer reactions that form the fundamental units for the varied multitude of biologic processes [15-17]. In addition, when compared to metals or ceramics, the modulus or stiffness of polymer composites (Table 1) can be engineered to accommodate stress-transfer conditions with surrounding bone tissue and associated living cells [17]. Modulus mismatch between bone and metals consequently has been a problem with current implant loosening related to stress transfer between the bone and implant [20].…”

Compatibility of interfaces and fibers for SiC-composites in fusion environments

“…The use of the K Q values is understood to be a qualitative measure of fracture toughness for these materials as defined in ASTM E399-90 [42]. A recent discussion of fracture toughness measurements in composites points out the difficulties in these measurements [43]. We examine the effect of loss of fiber strength due to an unspecified interaction with a corrosive liquid or gas.…”