On scale effects in composite modeling

Larissa Gorbatikh

Department of Mechanical EngineeringThe University of New Mexico

Co-Sponsored by the National Science Foundation, the US Department of Energy and the American Plastics Council, June 9-10, 2004, Arlington, Virginia

Increased demand for

ApplicationsMedical industry, Telecommunications, Automotive industry , Consumer electronics, etc (less-invasive surgical devices, sensors, tubes, implants, actuators, rotors, lenses, fiber-optic components, etc)

Micro-molding Nano-composites

parts super smallsuper lightlow cost

materials with novel advanced properties Above is a radio frequency

carrier molded in LCP plastic.(Taken from the article ”Miniature Tool & Die is helping to mold the micro market” by Matt Kelly, Small Times)

Larissa Gorbatikh, Mechanical Engineering, University of New Mexico

Problem of Scales

Current State Parts: <0.0001g

<0.1cub mm

Micro-molding Today

Challenges:-- no standard tooling is available -- rules for traditional molding are not applied-- the lack of proven methods trial and error approach

-- new techniques for ultra small mold making (reactive etching, laser lithography, etc )

-- new injection machines (study of microfluidics, etc)

-- new part handling and inspecting systems (strong microscopes)

-- new prediction techniques and simulation software -- search for new materials and reinforcements in depth investigation of scale effects

Question to ask:-- limits of micromolding (possibility of nanomolding, molding without a mold, etc)

Improvements needed:

Larissa Gorbatikh, Mechanical Engineering, University of New Mexico

Multi-scale Material Modeling Today

Quantum mechanics m1210

Molecular dynamics (MD) m910

Continuum mechanics (CM) m610

m310Mechanics of materials

Structural mechanics m010

Bottom-up approach

Top-down approach

Bridging scales Novel properties

Larissa Gorbatikh, Mechanical Engineering, University of New Mexico

Investigation of Scale-dependent microstructure-property relations for composite materials (top down)

Our approach

Concentrated effort is needed to develop explicit links between atomistic and continuum mechanics models.

Scale-dependent microstructure-property relations for composite materials

• Identify underlying mechanisms responsible for the existence of size effects when approaching nano-scale. Investigate the role of surface/ interface energy and stress in laws of nano-mechanics.

• Re-examine Eshelby problem for a single inhomogeneity by incorporating new effects into elastic solutions (driven by intermolecular forces). Derive compliance of a single nano-sized elastic inhomogeneity.

• Investigate interaction between inhomogeneities. Raise the question of the existence of homogenization techniques equivalent to the classical ones.

• Introduce a concept of crack-like flaws in nanomaterials, describe their characteristic properties and relate them to the material property degradation on nanoscale.

• Investigate the impact of microstructural parameters of the material on its effective properties. Provide a physical insight on the existence of new phenomena.

• The final product can be envisioned in the form of “a roadmap” to guide further advances in property prediction of composite materials with nano-scale structures.

Our objectives:

Larissa Gorbatikh, Mechanical Engineering, University of New Mexico

Larissa Gorbatikh, Mechanical Engineering, University of New Mexico

• building teams with appropriate cross-disciplinary mix of expertise• finding access to high tech (costly) equipment and facilities • bringing together manufacturing and science research (industry and academia)• creating new infrastructure to support such complex interactions • preparing new generation scientists• …

Requirements

• Understand mechanisms of deformation at the interface between matrix and inclusion in nanocomposites• Understand fluid/surface interactions and fluid properties in nanofluidic applications• Establish fundamental structure-property-processing-performance relationships for nanocomposites

Short term technical goals:

Highly Complex Problems