Research Assistant

Xiaoyu Zhang

**** **** ***. *., ***** ***, Nashville, TN, 37212 615-***-**** ******.*****.*****@*****.***

SUMMARY

PhD research focused on computational mechanics with finite element method

Explicit finite element analysis of composites subjected to dynamic/transient loadings

Development of crystal plasticity finite element models (CPFEM) in ABAQUS VUMAT

Machine-learning-based parameter sensitivity analysis and uncertainty quantification

EDUCATION

Vanderbilt University, Nashville, TN

Ph.D. student, Civil Engineering August 2015 ~ January 2021

Beihang University (Beijing University of Aeronautics and Astronautics), Beijing, China

B.S., Engineering Mechanics August 2010 ~ July 2014

EXPERIENCE

1. Uncertainty quantification for Fatigue Nucleation in Titanium Alloy Jan. 2020 ~ Present

Research Assistant, Vanderbilt University, USA

Predicted fatigue nucleation for Ti6242 with emphasis on the effect of microstructure geometric features on fatigue nucleation parameter

Accelerated the fatigue nucleation prediction by incorporating the sparse and scalable Eigenstrain based reduced order Homogenization Model (EHM) into Dislocation Density informed EHM

Generated microstructures of Ti6242 with assigned features, for instance, the colony grain volume fraction and alpha/beta lath thickness in the lamellar structure

2. Shock dynamic simulation of polycrystal materials May 2019 ~ June 2020

Research Assistant, Vanderbilt University, USA

Captured the large volumetric change of energetic materials subjected to shock loadings using Equation-Of-State in the Crystal Plasticity Finite Element (CPFE) formulation

Established the deformation twinning model (distinguished from dislocation slip) for -HMX

Investigated material behaviors (large volume change, twinning and slip) at shock loading rate

3. Crystal plasticity finite element modeling under sub-shock loading Sep. 2017 ~ May 2019

Research Assistant, Vanderbilt University, USA

Formulated a CPFE model to describe the monoclinic elasticity and viscoplasticity behavior of HMX energetic polycrystal subjected to impact (weak shock) loading

Proposed a constitutive law for dislocation slip to capture the dislocation slip motion at slow (< 1m/s) and faster speed (> 1 m/s) using two distinguished mechanisms

Elucidated the effects and relative roles of various deformation mechanisms on the dynamic response of the composite through the proposed global sensitivity analysis framework

4. Machine-Learning-based sensitivity analysis framework Sep. 2015 ~ Dec. 2017

Research Assistant, Vanderbilt University, USA

Established a parameter sensitivity analysis framework for damage and failure modeling of polymer-bonded explosives subjected to transient loading

Captured the discontinuity in response surfaces by integrating the Gaussian Process model with a support vector machine (SVM) classification algorithm

Identified the dominant and non-dominant material properties and mesostructure morphology parameters of polymer-bonded explosives through Sobol’s sensitivity indices

KNOWLEDGE and SKILLS

Knowledge base:

Crystal plasticity finite element method, Computational solid mechanics, Shock dynamics

Uncertainty quantification, Machine Learning algorithms

Programming languages:

Fortran, Python, Matlab, C

Software skills:

ABAQUS VUMAT

LS-DYNA, NASTRAN, AutoCAD, CATIA

PUBLICATIONS

Xiaoyu Zhang, Caglar Oskay, “Plastic dissipation sensitivity to mechanical properties in polycrystalline -HMX subjected to impact loading.” Mechanics of Materials, 138 (2019): 103079. DOI: https://doi.org/10.1016/j.mechmat.2019.103079

Xiaoyu Zhang, Caglar Oskay, “Material and morphology parameter sensitivity analysis in particulate composite materials.” Computational Mechanics, 62, no. 3 (2018): 543-561. DOI: https://doi.org/10.1007/s00466-017-1512-2

Xiaoyu Zhang, Caglar Oskay, “Uncertainty Quantification for Fatigue Nucleation in Titanium Alloy Bi-model Microstructure.” Prepare for submission, 2021.

Xiaoyu Zhang, Caglar Oskay, “Modeling and Numerical Investigation of Mechanical Twinning within β-HMX Crystal Subjected to Shock Loadings.” Under review, 2021.

CONFERENCES

Xiaoyu Zhang, Caglar Oskay, “Uncertainty Quantification for Fatigue Nucleation in Titanium Alloy.” Abstract accepted, AIAA SciTech Forum 2021

Xiaoyu Zhang, Caglar Oskay, “Sensitivity analysis and variability assessment of the dynamic response of polycrystalline energetic materials subjected to impact loading.” 15th US National Congress on Computational Mechanics, Austin, TX, 2019

Xiaoyu Zhang, Chandra Prakash, Vikas Tomar and Caglar Oskay, “Experimental and computational investigations of interface chemistry dependence and parameter sensitivity of dynamic response and fracture in energetic materials.” Gordon Research Seminar (Energetic Materials), Newry, ME, 2018.

Xiaoyu Zhang, Caglar Oskay, “Material and morphology parameter sensitivity analysis in polymer-bounded polycrystalline energetic materials”, MACH Conference, Annapolis, MD, 2018.

Xiaoyu Zhang, Caglar Oskay, “Material properties and morphology parameters sensitivity analysis in energetic materials.” 14th US National Congress on Computational Mechanics, Canada, 2017.

HONORS AND AWARDS

Vanderbilt Graduate School Travel Award 2019

Vanderbilt Graduate School Travel Award 2017

Outstanding Undergraduate Student (Beihang University) 2014

National Grant 2014

Academic Excellence Scholarship 2012

Student Leadership Award (Beihang University) 2011

Outstanding Social Work Award 2011

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