Robert P. Lipton

Nicholson Professor Louisiana State University

  • Baton Rouge LA

Dr. Lipton works on the multi-scale analysis of heterogeneous media.

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Louisiana State University

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Biography

Robert Lipton works on the multi-scale analysis of heterogeneous media. Lipton's research includes the following areas: Identification of new wave phenomena due to sub-wavelength resonances and multiple scattering. Accurate multi-scale analysis of heterogeneous media with non well separated length scales. Non-local modeling for understanding the fracture process and the creation of interface. Chacterizing the macroscopic effect of the microstructure on strength. Identifying the macroscopic effect of microscopic interfaces. Extraction of the effect of microstructure on extreme elastic properties.

Areas of Expertise

Heterogeneous Media
Advanced Composites
Wave Propagation
Metamaterials
Photonics

Research Focus

Wave Propagation & Metamaterials

Dr. Lipton’s research focuses on multiscale analysis of heterogeneous media, photonics and metamaterials, wave propagation, and fracture in advanced composites. He develops homogenization and nonlocal PDE frameworks to capture subwavelength resonances, dispersion, and damage evolution, informing transformational electromagnetics and the design of strong materials as LSU’s Nicholson Professor of Mathematics.

Education

NYU

Ph.D.

Mathematics

1986

NYU

M.S.

Mathematics

1984

University of Colorado

B.S.

Electrical Engineering

1981

Accomplishments

LSU Distinguished Research Master Award and University Medal

2021

Fellow, American Mathematical Society

2020

Fellow, Society for Industrial and Applied Mathematics

2020

Media Appearances

LSU Math Professor Robert Lipton Secures $1.25 Million MURI Award to Help Improve Materials Durability

Louisiana State University  online

2024-04-03

"I'm interested in the dynamics of extreme deformation in material structures. And by extreme deformation, I mean ripping things apart and blowing things up," explains LSU Mathematics professor Robert Lipton. His research aims to enhance the understanding of damage propagation in heterogeneous materials.

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Microwaving Saturn

WRKF 89.9  radio

2016-02-01

For most people, a microwave means a quick way to "nuke" your food.

But for LSU Math Professor Dr. Robert Lipton, a microwave means another thing: “Deep space communications – like how do you control the Mars Rover? They can use microwaves or radiowaves.”

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Articles

Energy balance and damage for dynamic fast crack growth from a nonlocal formulation

Journal of Elasticity

2025

A nonlocal model for dynamic brittle damage is introduced consisting of two phases, one elastic and the other inelastic. Evolution from the elastic to the inelastic phase depends on material strength. Existence and uniqueness of the displacement-failure set pair follow from an initial value problem describing the evolution. The displacement-failure pair satisfies energy balance. The length of nonlocality ϵ is taken to be small relative to the domain in R d, d= 2, 3. The strain is formulated as a difference quotient of the displacement in the nonlocal model. The two point force is expressed in terms of a weighted difference quotient and delivers an evolution on a subset of R d× R d. This evolution provides an energy balance between external energy, elastic energy, and damage energy including fracture energy.

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Macroscopic effects of intraparticle fracture, grain topology and shape on vehicle dynamics and mobility over gravel road beds

Granular Matter

2025

The hybrid particle-based computational platform that couples peridynamics with the discrete element method (PeriDEM) is used to model vehicle mobility over roadbeds. We consider wheels rolling over gravel beds, where gravel is allowed to deform and fracture. The motion of particles are not constrained to translation and rotation as in DEM and grains can deform elastically or inelastically. This allows for more modes of inter-particle interaction. The effects of gravel shape and topology on the vehicle mobility are examined using the higher fidelity modeling. Here we study how these aspects affect vehicle range, average vehicle velocity, traction as measured by wheel slip, as well as the overall energy needed to travel a prescribed distance.

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Nodal finite element approximation of peridynamics

Computer Methods in Applied Mechanics and Engineering

2025

This work considers the nodal finite element approximation of peridynamics, in which the nodal displacements satisfy the peridynamics equation at each mesh node. For the nonlinear bond-based peridynamics model, it is shown that, under the suitable assumptions on an exact solution, the discretized solution associated with the central-in-time and nodal finite element discretization converges to a solution in the L 2 norm at the rate C 1 Δ t+ C 2 h 2/ϵ 2. Here, Δ t, h, and ϵ are time step size, mesh size, and the size of the horizon or nonlocal length scale, respectively. Constants C 1 and C 2 are independent of h and Δ t and depend on norms of the solution and nonlocal length scale. Several numerical examples involving pre-crack, void, and notch are considered, and the efficacy of the proposed nodal finite element discretization is analyzed.

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Affiliations

  • American Association of the Advancement of Science (AAAS)
  • Society for Engineering Science (SES)
  • American Mathematical Society (AMS)
  • Society for Industrial and Applied Mathematics (SIAM)
  • Society for Natural Philosophy (SNP)
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Event Appearances

Fracture as Emergent Phenomena

2024 | PDEs and Applied Mathematics “Celebration of Session 100th”  Online

Dynamic Brittle Fracture as a Well Posed Nonlocal Initial Value Problem

2024 | Hausdorff Reasearch Institute for Mathematics  Bonn, Germany

Multiscale Problems: Algorithms, Numerical Analysis and Computation

2024 | Hausdorff Institute  Bonn, Germany

Research Grants

Complexity, Nonlocality, and Uncertainty in Heterogeneous Solids

ARO MURI

2024-2028

Title: Designing Mutable Metamaterials with Photo-Adaptive Meta-Atoms

NSF DMREF 1921707

2019-2024

Predicting and Controlling the response of Particulate Systems through Grain Scale Engineering

ARO MURI

2019-2025