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Lecture

Physically Based Constitutive Models

In course

ME-628: High Strain Rate Mechanics of Materials

This course offers fundamentals concepts of material behavior under dynamic loads such as impact and shock. lt will cover experimental methods and analytical modeling approaches to describe the dynamic deformation behavior of metals, ceramics and polymeric ...

Description

This lecture covers the development of constitutive models based on physical principles, focusing on the high strain rate behavior of materials and the evolving microstructure during deformation. It discusses the obstacles dislocations face, such as Peierls-Nabarro forces, and the role of thermal energy in dislocation motion. The lecture also explores the rate dependency of plastic response, the interaction of dislocations with defects, and the constitutive equations derived from activation barriers. Additionally, it delves into the strain rate sensitivity of materials and the evolving microstructure's impact on stress-strain behavior.

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Ontological neighbourhood

Chemical engineering

Materials science: Deformation of materials

Related concepts (32)

Plastic pollution

Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and microbeads) in the Earth's environment that adversely affects humans, wildlife and their habitat. Plastics that act as pollutants are categorized by size into micro-, meso-, or macro debris. Plastics are inexpensive and durable, making them very adaptable for different uses; as a result, manufacturers choose to use plastic over other materials.

Marine plastic pollution

Marine plastic pollution (or plastic pollution in the ocean) is a type of marine pollution by plastics, ranging in size from large original material such as bottles and bags, down to microplastics formed from the fragmentation of plastic material. Marine debris is mainly discarded human rubbish which floats on, or is suspended in the ocean. Eighty percent of marine debris is plastic. Microplastics and nanoplastics result from the breakdown or photodegradation of plastic waste in surface waters, rivers or oceans.

Dislocation

In materials science, a dislocation or Taylor's dislocation is a linear crystallographic defect or irregularity within a crystal structure that contains an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to slide over each other at low stress levels and is known as glide or slip. The crystalline order is restored on either side of a glide dislocation but the atoms on one side have moved by one position. The crystalline order is not fully restored with a partial dislocation.

Biodegradable plastic

Biodegradable plastics are plastics that can be decomposed by the action of living organisms, usually microbes, into water, carbon dioxide, and biomass. Biodegradable plastics are commonly produced with renewable raw materials, micro-organisms, petrochemicals, or combinations of all three. While the words "bioplastic" and "biodegradable plastic" are similar, they are not synonymous. Not all bioplastics (plastics derived partly or entirely from biomass) are biodegradable, and some biodegradable plastics are fully petroleum based.

Plastic pellet pollution

Plastic pellet pollution is a type of marine debris originating from the plastic particles that are universally used to manufacture large-scale plastics. In the context of plastic pollution, these pre-production plastic pellets are commonly known as 'nurdles'. These microplastics are created separately from the user plastics they are melted down to form, and pellet loss can occur during both the manufacturing and transport stages. When released into the open environment, they create persistent pollution both in the oceans and on beaches.

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Covers plastic deformation, dislocation model, stages, shear stress, distortion, dislocation loops, strain hardening, and crystal growth.

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Introduces internal stress and strain, material properties, and design considerations for axial loads and direct shear.

Kinetics of Dislocations

Explores the kinetics of dislocations, stress fields, and interactions with point defects and extended defects.

Shear and Bearing Stresses

Explores shear and bearing stresses, including plasticity, creep, Hooke's Law, and allowable stresses in engineering design.

Materials: from Chemistry to Properties