Oscar Lopez-Pamies

Professor of Civil Engineering @Illinois_Alma

[Oscar Lopez-Pamies @LPamiesOscar]

@CretonCost @zhigangsuo @ProfZhaoMIT @lin_shaoting @Tengh_Yin @ShengqiangCai @lihuajin2014 @CiccottiMatteo @CohenMechGroup @aljcrosby The comparisons with the poker-chip experiments suggest that the strength correlates with the cross-link density of the elastomer, but not in the same way as the initial Young’s modulus. More work is needed to figure out precisely how...

[Oscar Lopez-Pamies @LPamiesOscar]

@jdolbow @zhigangsuo @CretonCost @ProfZhaoMIT @lin_shaoting @Tengh_Yin @ShengqiangCai @lihuajin2014 @CiccottiMatteo @CohenMechGroup @aljcrosby Indeed, nearly incompressible materials like elastomers can concentrate stress without concentrating strain energy. Classical phase-field models break down in this limit! The drawback applies to compressible materials too, not just elastomers, under complex states of stress.

[Oscar Lopez-Pamies @LPamiesOscar]

@zhigangsuo @CretonCost @ProfZhaoMIT @lin_shaoting @Tengh_Yin @ShengqiangCai @lihuajin2014 @CiccottiMatteo @CohenMechGroup @aljcrosby @AdityaWKumar Our theory is macroscopic. We only model the macroscopic manifestation of the inherent defects: the strength. Indeed, the material inputs in our theory are the elasticity, strength, and toughness, as obtained from experiments carried out at length scales of microns or larger.

[Oscar Lopez-Pamies @LPamiesOscar]

@zhigangsuo @CretonCost @ProfZhaoMIT @lin_shaoting @Tengh_Yin @ShengqiangCai @lihuajin2014 @CiccottiMatteo @CohenMechGroup @aljcrosby @AdityaWKumar The elasticity view initiated by Gent-Lindley ('59), & the fracture one by Williams-Schapery ('65), are mesoscopic theories: they model explicitly defects where fracture initiates from. But inherent defects are submicron and their geometry/constitutive behavior is not well known