Deformation and Fracture Structures

PS-PBMA diblock copolymer (67% PS) with lamellar morphology, deformation [1, 16]  

SBM diblock copolymer with 76% PS having hexagonally packed PBMA cylinders in the PS matrix, deformed [1, 16]  

SB block copolymer with parallel lamellae, deformed  

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For some blends containing one or more amorphous polymers together with one or more semicrystalline polymers, the phase distribution and the interface are demonstrated using electron microscopic techniques in combination with different preparation methods. Additionally, deformation and fracture structures are presented ... 

The most common conditions of possible failure are elastic deflection, inelastic deformation, and fracture. During elastic deflection a product fails because the loads applied produce too large a deflection. In deformation, if it is too great it may cause other parts of an assembly to become misaligned or overstressed. Dynamic deflection can produce unacceptable vibration and noise. When a stable structure is required, the amount of deflection can set the limit for buckling loads or fractures. 

Klemm H, Herrmann M, Schubert C (1996) The Influence of the Grain Boundary Phase Composition on the High Temperature Properties of Silicon Nitride Materials. In Parilak L, Danninger H, Dusza J, Weiss B (eds) Proc Int Conf Deformation and Fracture in Structural PM Materials, IMR SAS Kosice 2 75... 

Abstract The fracture properties and microdeformation behaviour and their correlation with structure in commercial bulk polyolefins are reviewed. Emphasis is on crack-tip deformation mechanisms and on regimes of direct practical interest, namely slow crack growth in polyethylene and high-speed ductile-brittle transitions in isotactic polypropylene. Recent fracture studies of reaction-bonded interfaces are also briefly considered, these representing promising model systems for the investigation of the relationship between the fundamental mechanisms of crack-tip deformation and fracture and molecular structure. 

The macroscopic properties such as mechanical behavior of block copolymers or polymer blends depend directly on the relative concentrations of different constituents and their meso-structures. How to predict the exact macroscopic properties of polymer blends or block copolymers with meso-phase separation structures from pure component properties remains a big challenge. Some theoretical efforts have been explored. For example, Buxton et al. found that the deformations and fractures of polymer blends can be described by the... 

To study the influence of these structural parameters on the micromechanical mechanisms of toughening, several techniques of electron microscopy were used. Electron microscopic techniques allow investigations not only of detailed morphology but also of the micromechanical processes of deformation and fracture (3, 9-11). 

Time-Dependent Fracture. (This is not an established term.) In this regime, which is frequently observed in soft-solid foods, the whole test piece shows lasting deformation and hence structural breakdown before fracture occurs. Because of this, the fracture phenomena will depend on time scale. The resulting fragments do not lit each other at all. 

Thus, modern methods of nonequilibrium mechanical tests do not allow identification of deformation and fracture conditions of concrete samples, which leads to an ambiguous evaluation of structural material properties, in particular, the crack resistance of a concrete. 

One more feature of structural defects that determines their role in the adsorption-induced strength decrease is that in most cases the penetration of liquid phase specifically along the defects facilitates the delivery of adsorption-active medium into a pre-fracture zone, and thus allows the medium to influence the development of cracks. In this sense the role of structural defects is closely related to the role of conditions under which deformation and fracture takes place. With respect to discussed case, these are the conditions under which penetration of active medium into the zone of crack formation and development takes place. 

A basic building block of the bone is the mineralized collagen fibril. With various percentages of mineralization, different types of bones have specialized properties for their own purposes. As with other biomaterials, the atomistic mechanical properties of its basic constitutive units are strongly correlated with their chemical bond network induced by their structural stability, and their reactivity during deformation and fracture. 

The mechanisms responsible for fracture in structural ceramics at elevated temperatures have been reviewed [154]. Sensitivity to flaws or microstructural inhomogeneities which nucleate microcracks are among the failure mechanisms. The flaws which control failure under creep conditions are different from those responsible for fast fracture at room temperature. A common feature is the development of cracks through gradual damage accumulation, depend on the microstructure. The role of cracks in the deformation and fracture behavior of polycrystalline structural ceramics have been reviewed [155]. 

S. Luyckx, V. Richter, D. G. F. O Quigley, and L. Makhele, Proc. Int. Conf. Deformation and Fracture in Structural Materials, Institute of Materials Research, Slovak Academy of Science, Kosice, Slovakia, 1996, 2, 109. 

Schneider, K. et al. (2011). Online structure investigation during deformation and fracture using synchrotron radiation. Proceedings of 13. Problemseminar "Deformation und Brnchverhalten von Kunststoffen", CD-ROM, ISBN 978-3-86829-400-2, Halle-Merseburg, 29.6.-1.7.2011, pp. 122-130... 

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