Strain- and stress-based continuum damage models—I. Formulation

Encapsulation of drugs within nanocarriers that selectively target malignant cells promises to mitigate side effects of conventional chemotherapy and to enable delivery of the unique drug combinations needed for personalized medicine. To realize this potential, however, targeted nanocarriers must simultaneously overcome multiple challenges, including specificity, stability and a high capacity for disparate cargos. Here we report porous nanoparticle-supported lipid bilayers (protocells) that synergistically combine properties of liposomes and nanoporous particles. Protocells modified with a targeting peptide that binds to human hepatocellular carcinoma exhibit a 10,000-fold greater affinity for human hepatocellular carcinoma than for hepatocytes, endothelial cells or immune cells. Furthermore, protocells can be loaded with combinations of therapeutic (drugs, small interfering RNA and toxins) and diagnostic (quantum dots) agents and modified to promote endosomal escape and nuclear accumulation of selected cargos. The enormous capacity of the high-surface-area nanoporous core combined with the enhanced targeting efficacy enabled by the fluid supported lipid bilayer enable a single protocell loaded with a drug cocktail to kill a drug-resistant human hepatocellular carcinoma cell, representing a 10(6)-fold improvement over comparable liposomes.

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The targeted delivery of multicomponent cargos to cancer cells by nanoporous particle-supported lipid bilayers

On energy-based coupled elastoplastic damage theories: Constitutive modeling and computational aspects

Computational strategies for masonry structures

Publisher Summary This chapter discusses some basic problems in mechanics of elastic solids containing multiple cracks. A number of mathematical aspects that frequently constitute fields of their own (like various numerical techniques) are discussed very briefly in the chapter. The focus is on physically important effects produced by crack interactions and to present results in the simplest form possible. The problems considered in this chapter can be divided into two groups: (1) The impact of interactions on individual cracks, particularly on the stress intensity factors (SIFs), and (2) the effective elastic properties of solids with many cracks. Problems of the first group are, generally, relevant for the fracture-related considerations; solutions are sensitive to the positions of individual cracks. Problems of the second group deal with the volume average quantities; they are relatively insensitive to the information on individual cracks. The chapter discusses, in this connection, whether correlations exist between these two groups of quantities; in particular, whether microcracking can be reliably monitored by measuring changes in the effective elastic moduli.

Elastic Solids with Many Cracks and Related Problems

The present work analyzes the implication and limitation of some 'scalar damage' models. In particular, the elastic-damage thermodynamic potential and the 'effective stress concept' are re-examined. It is demonstrated that 'isotropic damage' does not necessarily imply 'scalar damage' representation in general. The notion of isotropic and anisotropic damage variables in continuum damage mechanics is then discussed. In addition, some results from micromechanical analyses are applied to show the direct relationship between the fourth-order damage tensor and the damage-induced compliance tensor characteristic of microcrack-weakened brittle materials.

On Isotropic and Anisotropic Damage Variables in Continuum Damage Mechanics

In this paper, the standard version of the inviscid twoinvariant cap model is considered and a viscoplastic ratedependent generalization is proposed For the inviscid case, a new algorithm is propo

Assessment of cap model: consistent return algorithms and rate-dependent extension

Global damage indices based on equivalent modal parameters are defined using the vibrational parameters of an equivalent linear structure. In continuum mechanics‐based damage models, effects of the growth and coalescence of microcracks are accounted for through the definition of an internal or local damage variable. Damage to engineering materials essentially results in a decrease of the free energy stored in the body with consequent degradation of the material stiffness. It is shown that parameter‐based global damage indices can be related to local damage variables through operations of averaging over the body volume. The relationship obtained is applied to the case of numerical simulations of damage events as well as to the case of actual structures tested on shaking tables. Some results are also presented, relating parameter‐based global damage indices to averages in space and time of local plastic strain.

Relation between Global Damage Indices and Local Stiffness Degradation

A micromechanical damage model for effective elastoplastic behavior of ductile matrix composites considering evolutionary complete particle debonding

To simulate the evolution process of interfacial debonding between the matrix and reinforcing particles, and to further estimate its effect on the overall elastic behavior of particle-reinforced co...

J. W. Ju

Papers

On Isotropic and Anisotropic Damage Variables in Continuum Damage Mechanics

Assessment of cap model: consistent return algorithms and rate-dependent extension

Relation between Global Damage Indices and Local Stiffness Degradation

A micromechanical damage model for effective elastoplastic behavior of ductile matrix composites considering evolutionary complete particle debonding

An Interfacial Debonding Model for Particle-Reinforced Composites