RESEARCH
Metal Mechanics Composite Mechanics

a. Design of variable stiffness composites

    i. Strain Energy Minimization

Design methodology for variable stiffness composites: optimization for compliance using lamination parameters as the variables, conversion of lamination parameters to fiber angles, application of curvature constraints to find manufacturable fiber angle distribution for a simply-supported plate with a pressure load.

    ii. Buckling load maximization

Preliminary results of buckling optimization to find best fiber angles for an axially compressed plate with fixed edges.

   iii. Application to 3D printing of PLA material with chopped carbon fibers (collaboration with Dr. Thomas Cender)

Variable stiffness design of an open hole tension specimen followed by path planning and 3D printing, respectively 

Mechanics of Solids (MFG 512): syllabus (link to syllabus_MFG512.pdf)

Advanced Finite Element Method (MFG 513): syllabus (link to syllabus_MFG513.pdf)

Computer Aided Design (ENS 209): syllabus (link to syllabus_ENS209.pdf)

Computer Aided Engineering (ENS 309): syllabus (link to syllabus_ENS309.pdf)

Graduation Project Course (ENS491/2): some photos from graduation projects

 

Miniaturized glass fiber-reinforced leaf spring design, manufacturing, and testing.

  

Design, analysis, and manufacturing of a composite plastic material for a safety railing of a children’s playground.

 

 



Carbon fiber-reinforced composite wheel rim project

    

Carbon fiber-reinforced bicycle design and manufacturing

    



A hole drilling system design for residual stress measurements

  

 

 

Metal Mechanics

a. Crystal plasticity (Multi-scale)

    i. Material point models

       1. Single crystal plasticity: anisotropy, strain-rate and temperature dependence

 

 

 

 

 

 

 

BCC single crystal tensile behavior at 298 K – Effect of crystal orientation

      2. Polycrystal plasticity (texture simulations)

Simulation of texture evolution for random initial orientations for uniaxial tension load case: Texture pole figures along <110> and <111> crystallographic directions.

   ii. Physics based constitutive modeling

Temperature and orientation dependence of FCC materials: a better fit can be obtained through physical models in comparison temperature independent classical models.

   iii. Single crystal finite element model

Goss compression of an FCC single crystal a. before deformation, b. after deformation.

   iv. Polycrystal finite model (RVE)

Polycrystal simulation of an Aluminum sample with large grains –Each color represents a grain.

Crystal plasticity simulation of metal forming process using a simplified polycrystal RVE for DP600 steel material.

b. Thermomechanical finite element process simulation for Metal Additive Manufacturing

   i. Powder bed fusion process

Video file comes here! Below is the caption. Video

Thermal simulation of powder bed fusion process as a metal 3D printing process.

   ii. Powder bed fusion process

Video file comes here! Below is the caption. Video

Thermal simulation of directed energy deposition process a metal 3D printing process.

c. Single crystal micro machining model

Simulation of turning process for FCC single crystals and cutting force fluctuations for different crystallographic turning zone axes a. <100>, b. <110>, c. <111>, d. schematic sketch for the turning zone axis.

d. Residual stress analysis method

    i.Hole drilling method (experimental)

Vishay RS200 to measure residual stresses using hole drilling method according to the ASTM Standard E837.

    ii. X-ray Diffraction (at Cornell University – with Prof. P.R. Dawson)

Two scale analysis methodology to find the macro scale stress distributions from lattice strain measurements (Images are taken from the reference: Demir E., Park J.S., Miller M.P. and Dawson P.R., Computer Methods in Applied Mechanics and Engineering, vol. 265, pp. 120-135, 2013.)

e. Micromechanics

    i. Size dependence and GNDs (at Max Planck Institute for Iron Research with Prof. D. Raabe)

A method to compute geometrically necessary dislocations is developed and applied analyze Electron Backscattered Diffraction (EBSD) maps underneath indents to explain indentation size effect

    ii. Micro scale experiments (at Max Planck Institute for Iron Research with Prof. D. Raabe)

Various single crystal Copper samples prepared by Focused Ion Beam (FIB) milling method: Beams with round cross-section, cantilever beam during manufacturing, Bauschinger test sample and its EBSD map (from left to right).

 

 

Ali Rashed (PhD Student)

Thesis Topic: Design of variable stiffness fiber-reinforced composites for maximum fundamental frequency and maximum critical buckling load criteria and their aerospace application (supported under TUBITAK grant no. 218M715)

Can Bayraktar (Masters Student)

Thesis Topic: Thermomechanical Finite Element model for Powder Bed Fusion – a metal 3D printing process (supported from Sabanci University Teaching Fellowship) 

Faraz Ganjdoust (Masters Student)

Thesis Topic: Development of a continuum damage model for fiber-reinforced composites and its application to Finite Element Models (supported under TUBITAK grant no. 217M211)

Kerem Dörtkaşlı (Masters student)

Thesis Topic: Thermal Finite Element modeling of Directed Energy Deposition – a metal 3D printing process (currently working at Turkish Engine Industry - TEI)

Mohammad Hasan Joudivand Sarand (PhD student)

Thesis Topic: Crystal plasticity finite element modeling of DP600 multi-phase steel: single crystal bcc model development, polycrystal RVE application, multi-phase steel modeling (supported under TUBITAK grant no. 118M285)

Ram Kumar Kesharwani (Post-Doctoral researcher)

Research Focus: Application of Crystal Plasticity Finite Element models for DP600 steel to metal forming applications (supported under TUBITAK grant no. 118M285)

Sina Khalilvandi Behrouzyar (PhD student)

Thesis Topic: Development of an efficient thermomechanical finite element process model, distortion correction methods, and application to an aerospace component (supported under TUBITAK grant no. 218M712)

Alumni

 

Canset Mercan (Masters student) Currently working at TEI-TUSAS

Thesis Topic: A physics-based single crystal plasticity model for crystal orientation and length scale dependence of machining response.

Torkan Shafighfard (Masters student)

Thesis Topic: Design of variable stiffness composites using finite element method: method development, design of open hole geometries, and application to 3D polymer printing (supported from Sabanci University Teaching Fellowship)