Composites toughness

U. Khan, P. May, A. O Neill, J.N. Coleman, Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane, Carbon, 48 (2010) 4035-4041. 

Gillespie Jr., J.W., Carlsson, L.A. and Pipes, R.B. (1986). Finite element analysis of the end notched flexure (ENF) speeimen measuring mode II fraeture toughness. Composites Sci. Technol. 26, 177. 

Tough Compositions. The toughness of a thermoplastic, rigid poly(urethane) (PU) can be markedly improved by incorporating ABS resin. The ABS resin is mass-polymerized. 

Fracture toughness, composites, angle ply laminates, new toughness test method... 

Applying fracture mechanics techniques to characterize brittle materials has become an important subfield of materials science, and a reasonable understanding of the relation between toughness, composition, and microstructure is available. Silicate glasses have toughness values of 0.7-1,0 MPam, alumina ceramics values of 4-5 MPam, and glass ceramics values of 1-4 MPam, (the fracture toughness of metals is often > 50 MPam "),... 

Where resistance to chipping and tearing is required, pure rubber must be compounded with carbon black to give it a tough composition and hardness of 60-65 on the Shore A scale. Such linings are used in chutes, hoppers, bunkers, dampers, etc. 

In postyielding fracture mechanics, the EWF concept has been successfully employed to characterize the fracture toughness of ductile polymers and tough composites due to its simplicity over conventional 7-integral analysis (70-75). The EWF approach involves the determination of the total fracture energy (Wf) of notched specimen. It can be divided into two components ... 

CVD is the most common method of depositing fiber coatings for composite systems because it is a conformal process that can deposit fairly uniform coatings on a wide variety of structures. CVD is perhaps the only method that has been used successfully to provide tough composites with acceptable mechanical properties. A wide variety of coatings have been deposited by CVD, including carbon, BN, silicon-doped BN, Si3N4, and SiC. 

The development of ceramic oxide composites has lagged behind the development of non-oxide composites because of the poor creep resistance of oxide fibers (compared to SiC fibers) and because of the lack of adequate oxide fiber coatings that promote fiber-matrix debonding. Recent advances in creep-resistant oxide fibers and progress on interface control has improved the potential for oxide ceramic composites in industrial and defense applications. However, an effective coating for oxide fibers that provides a weak fiber-matrix interface (and therefore tough composite behavior) remains to be demonstrated. As was discussed in Chapter 6, all oxide coating concepts discussed in the literature have been demonstrated with model systems rather than actual composite systems. 

Fligh-temperature equilibria of the extraordinarily hard borides with metallic melts bring about the opportunity for a pressureless liquid phase sintering and the fabrication of hard and simultaneously tough composites similar to hard metals but are also of interest in ceramic systems or coatings. In this section emphasis is put on binary and ternary borides which are in equilibrium with transition metals. 

The research for high-strength/high-toughness composites in the TiB2-transition metal systems resulted in many attempts to avoid brittle matrix phases and to introduce hardening particles while making use of the opportunity of liquid-phase... 

Sub Subramaniyan, A. K., Sun, C. T. Toughening polymeric composites using nanoclay Crack tip scale effects on fracture toughness. Composites Part A - Appl. Sci. Manufact. 38 (2007) 34-43. 

Corn husk fibers the tenacity of which is around 25% lower than that of jute can produce more durable and tough composites than jute due to the elongtaion ratio and work of rupture which are 13 times and 7 times greater than that of jute, respectively [7]. 

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