arXiv subjects

Yaozhong Zhang

Publications and source records attributed to Yaozhong Zhang.

5 recordsLinked to original sources

arXiv2026

Unravelling the mechanisms underlying crack initiation in additively manufactured steel

Metal additive manufacturing (AM) is increasingly adopted for safety-critical applications across the biomedical, aerospace, and energy sectors. However, many AM alloys exhibit substantially lower fracture toughness and shorter fatigue lives than their wrought counterparts, limiting their structural reliability. The microscale mechanisms governing this deficit remain obscured because the evolution of crack-tip deformation cannot be directly resolved using conventional characteriza-tion techniques. Here, we combine in situ multimodal synchrotron X-ray diffraction with phase-contrast tomography to directly observe the three-dimensional evolution of crack-tip plasticity dur-ing loading. We find that wrought steel develops a localized crack-tip process zone characterized by extensive geometrically necessary dislocation (GND) accumulation, effective stress relaxation, and crack-tip blunting. This plastic zone provides shielding of the crack tip by redistributing defor-mation and reducing the local driving force for crack initiation. In contrast, the AM alloy exhibits suppressed GND evolution, limited crack-tip blunting, and persistent elevated stresses over an ex-tended region ahead of the crack tip, indicating ineffective stress relaxation and premature crack initiation. These findings demonstrate that fracture resistance is governed by the spatial evolution of crack-tip plasticity, providing a mechanistic framework for improving the damage tolerance of AM structural alloys.

cond-mat.mtrl-sci↗

arXiv2022

Colouring the sculpture through corresponding area from 2D to 3D with augmented reality

With the development of 3D modelling techniques and AR techniques, the traditional methods of establishing 2D to 3D relation is no longer sufficient to meet the demand for complex models and rapid relation building. This dissertation presents a prototype development implemented that creating many- to-many correspondences by marking image and 3D model regions that can be used to colouring 3D model by colouring image for the end user. After comparing the three methods in the conceptual design, I chose the creating render textures relation to further development by changing to Zeus bust model and connecting the AR environment. The results of testing each part of the prototype shows the viability of the creating render textures relation method. The advantages of it are easy to build many-to-many relations and adaptable for any model with properly UV mapping. But there are still three main limitations and future work will focus on solving them, building a database to store relation information data and printing 3D coloured models in real world.

cs.HC↗

arXiv2020

Microsimulation of Energy and Flow Effects from Optimal Automated Driving in Mixed Traffic

This paper studies the energy and traffic impact of a proposed Anticipative Cruise Controller in a PTV VISSIM microsimulation environment. We dissect our controller into two parts: 1. the anticipative mode, more immediately beneficial when automated vehicle fleet penetration is low, and 2. the connected mode, beneficial in coordinated car-following scenarios and high automated vehicle penetrations appropriate for autonomous vehicle specific applications. Probabilistic constraints handle safety considerations, and vehicle constraints for acceleration capabilities are expressed through the use of powertrain maps. Real traffic scenarios are then modeled using time headway distributions from traffic data. To study impact over a range of demands, we vary input vehicle volume from low to high and then vary automated vehicle penetration from low to high. When examining all-human driving scenarios, network capacity failed to meet demand in high-volume scenarios, such as rush-hour traffic. We further find that with automated vehicles introduced which utilize probabilistic constraints to balance safety and traffic compactness, network capacity was improved to support the high-volume scenarios. Finally, we examine energy efficiencies of the fleet for conventional, electric, and hybrid vehicles. We find that automated vehicles perform at a 10% - 20% higher energy efficiency over human drivers when considering conventional powertrains, and find that automated vehicles perform at a 3% - 9% higher energy efficiency over human drivers when considering electric and hybrid powertrains. Due to secondary effects of smoothing traffic flow, energy benefits also apply to human-driven vehicles that interact with automated ones. Such simulated humans were found to drive up to 10% more energy-efficiently than they did in the baseline all-human scenario.

eess.SY↗

arXiv2010

The Classification of n-Lie Algebras

This paper proves the isomorphic criterion theorem for (n+2)-dimensional n-Lie algebras, and gives a complete classification of (n+1)-dimensional n-Lie algebras and (n+2)-dimensional n-Lie algebras over an algebraically closed field of characteristic zero.

math-ph↗

arXiv2010

Classification of (n+2)-dimensional n-Lie Algebras

We give a complete classification of (n+2)-dimensional n-Lie algebras over an algebraically closed field of characteristic $2$, and provide a isomorphic criterion theorem of (n+2)-dimensional n-Lie algebras.

math-ph↗