PhD student (M/F) in Soft Matter Physics : Multiscale analysis of fatigue and memory in disordered materials

Job Description

Thesis Subject

Understanding how disordered materials respond to repeated mechanical loading is crucial for predicting their durability and failure. Even weakly nonlinear deformations can induce microscopic plastic rearrangements, leading to fatigue and the emergence of mechanical memory, yet their microscopic origins remain poorly understood. This project aims to establish a quantitative multiscale experimental framework linking local plastic events to macroscopic fatigue and memory effects in disordered materials. To this end, we will combine rheology, light scattering, and optical imaging to simultaneously probe mechanical response and microstructural evolution under cyclic loading.

By comparing different systems across length scales, from microscopic rearrangements to bulk mechanical response, we aim to identify universal signatures of plasticity, fatigue, and memory, and to determine how these phenomena are governed by network topology and defect structure. This work will provide new experimental benchmarks for theories of disordered solids and establish predictive links between microstructure, nonlinear dynamics, and long-term mechanical degradation.

Your Work Environment

The successful candidate will work at C3M (ESPCI Paris) and LPENS (ENS Paris) on the following activities:
- Preparation and characterization of colloidal gels, polymer networks, and composite materials
- Measurement of microscopic dynamics under cyclic loading
- Investigation of fatigue and nonlinear mechanical response using advanced rheological protocols
- Design and fabrication of textile-based networks with controlled architectures
- Introduction and characterization of localized and distributed defects in fibrous networks
- Measurement of strain fields and non-affine displacements using optical imaging
- Quantification of interactions between defects and their role in damage accumulation
- Comparative analysis of particulate and fibrous systems to identify universal multiscale indicators of fatigue and memory
- Development of a fundamental understanding of the link between microscale plasticity and macroscopic mechanical degradation
Willing candidates will also have the opportunity to:
- Work at the interface of soft matter physics and mechanics of materials
- Interact with experimental and theoretical researchers across institutions
- Develop programming skills (Python, Matlab, C++, etc.) for data analysis

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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