arXiv subjects

Manman Hu

Publications and source records attributed to Manman Hu.

4 recordsLinked to original sources

arXiv2026

Brittle-to-ductile fracturing transition: A chemo-mechanical phase-field framework

In chemically reactive environments, the mechanical integrity of geomaterials is fundamentally compromised by solid matrix dissolution. In this study, we propose a fully coupled chemo-mechanical phase-field framework to capture the dynamic interplay between mineral dissolution and fracture propagation. A key feature of the proposed model is the dynamic coupling of local mass removal to the fracture length scale, while also incorporating the damage-accelerated reaction-diffusion processes. Our results capture the development of an enlarged fracture process zone driven by chemical mass removal. This chemically induced widening blunts the sharp crack tip, alleviating the near-tip stress concentrations and causing a pronounced degradation in material stiffness before failure. Furthermore, we reveal a distinct ductilization effect, characterized by a more gradual accumulation of damage and a delayed onset of macroscopic failure. We show that the transition between brittle and ductile failure modes is dictated by the competing timescales of chemical degradation and mechanical deformation. Highly acidic environments enhance matrix dissolution and promote ductile fracture, whereas rapid mechanical loading limits chemical interaction and preserves brittle failure mode.

cond-mat.mtrl-sci↗

arXiv2023

Dynamic Mechanism of Catastrophic Collapse: An New Perspective on Earthquake Physics

The collapse of man-made and natural structures is a complex phenomenon that has been studied for centuries. We propose a new approach to understanding catastrophic instabilities, based on the idea that they do not occur at the critical point, but rather develop out of the subcritical regime as short-lived extreme events. We use an extension of Onsager's reciprocal theorem to study the subcritical regime, and we show that excitable systems in this regime are attracted to a nonlocal equilibrium that defines the maximum entropy production of at least two interacting phases. In most cases, these feedback systems are arrested by dissipative processes at larger scale, but in rare cases they can form tensor networks of instabilities that ripple from the small scale to the largest scale, forming extreme events.

nlin.PS↗

arXiv2023

An integrated system built for small-molecule semiconductors via high-throughput approaches

High-throughput synthesis of solution-processable structurally variable small-molecule semiconductors is both an opportunity and a challenge. A large number of diverse molecules provide a possibility for quick material discovery and machine learning based on experimental data. However, the diversity of molecular structure leads to the complexity of molecular properties, such as solubility, polarity, and crystallinity, which poses great challenges to solution processing and purification. Here, we first report an integrated system for the high-throughput synthesis, purification, and characterization of molecules with a large variety. Based on the principle of Like dissolves like, we combine theoretical calculations and a robotic platform to accelerate the purification of those molecules. With this platform, a material library containing 125 molecules and their optical-electric properties was built within a timeframe of weeks. More importantly, the high repeatability of recrystallization we design is a reliable approach to further upgrading and industrial production.

physics.app-ph↗

arXiv2019

Cross-Diffusion Waves as a Mesoscopic Uncertainty Relationship for Multi-Physics Instabilities

We propose a generic uncertainty relationship for cross-diffusion (quasi-soliton) waves triggered by local instabilities through Thermo-Hydro-Mechano-Chemical (THMC) coupling and cross-scale feedbacks. Cross-diffusion waves nucleate when the overall stress field is incompatible with accelerations from local feedbacks of generalized THMC thermodynamic forces with generalized thermodynamic fluxes of another kind. Cross-diffusion terms in the 4 x 4 THMC diffusion matrix are shown to lead to multiple diffusional $P$- and $S$-wave solutions of the coupled THMC equations. Uncertainties in the location of local material instabilities are captured by wave scale correlation of probability amplitudes. Cross-diffusional waves have unusual dispersion patterns and, although they assume a solitary state, do not behave like solitons but have a quasi-elastic particle-like state. Their characteristic wavenumber and constant speed defines mesoscopic internal material time-space relations entirely defined by the coefficients of the coupled THMC reaction-cross-diffusion equations. These coefficients are identified here as material parameters underpinning the criterion for nucleation and speed of diffusional waves. Interpreting patterns in nature as features of standing or propagating diffusional waves offers a simple mathematical framework for analysis of multi-physics instabilities and evaluation of their uncertainties similar to their quantum-mechanical analogues.

nlin.PS↗