An investigation of fracture and fatigue in a metal/polymer composite

Abstract

This article presents the results of a combined experimental and analytical study of the fatigue and fracture behavior of a polymer/metal composite which was developed recently for self-lubricating applications in automotive engines that utilize liquefied natural gas as fuel. For comparison, the microstructure and the fatigue and fracture behavior of a nonpolymer-containing "matrix" material are also presented. Since the crack profiles observed in both systems under monotonic or cyclic loading reveal significant components of ligament bridging, micromechanics models are presented for the modeling of crack bridging. The resulting predictions of resistance-curve behavior are compared with measured resistance curves. The shielding effects of ligament bridging are also quantified under cyclic loading. The implications of the work are also discussed for the modeling of fatigue damage and fracture in polymer/metal coatings.

Corrosion properties of a complex multi‐phase martensitic stainless steel depending on the tempering temperature

“…At the same time, the amount of alloying elements in the austenite rises leading to its stabilisation [1][2][3]. The martensite start temperature (M S ) is consequently lowered, which may result in the formation of soft retained austenite [1,2,4]. However, the corrosion resistance increases with carbide dissolution, which is also due to enrichment of alloying elements in the austenitic parent phase [5,6].…”

Pull-out behavior of natural fiber from earth-based matrix

“…where a is the constraint/triaxiality factor (theoretically between 1 and 3 and taken as $ 3 in this study), 36 V f is the volume fraction of the reinforcement phase, L is the bridging length (the distance from the crack-tip to the last unfractured reinforcement), y is the uniaxial yield stress, and x is the distance from the crack face behind the crack-tip as described by Savastano et al 37 For large-scale crack bridging (LSB) conditions, the contribution to composite toughness due to crack bridging was also modeled 38,39 using a weighting function by Fett and Munz to estimate the weighted distributions of bridging traction across the crack faces. 40 The shielding from large scale bridging, ÁK lsb , is given by 38…”

Strength and fracture toughness of earth-based natural fiber-reinforced composites

“…where is the constraint/triaxiality factor (theoretically between 1 and 3 and taken as $3 in this study), 31 V f is the volume fraction of the reinforcement phase, L is the bridging length (the distance from the crack tip to the last unfractured reinforcement), y is the uniaxial yield stress, and x is the distance from the crack face behind the crack tip as described by Savastano et al 32 For LSB conditions, the contribution to composite toughness due to crack bridging 30,33 can be modeled. The model uses a weighting function by Fett and Munz 34 to estimate the weighted distributions of bridging traction across the reinforcements as shown schematically in Figure 1.…”

“…where is the constraint/triaxiality factor (theoretically between 1 and 3 and taken as $3 in this study), 31 V f is the volume fraction of the reinforcement phase, L is the bridging length, y is the uniaxial yield stress, and x is the distance from the last unfractured fiber to the crack tip. Also, h a, x ð Þ is the weighting function given by Fett and Munz as 34 where ''a'' is the crack length and ''w'' is the specimen width.…”