# Dr Yasemin Sengul Tezel

Senior Lecturer

- SengulTezelY@cardiff.ac.uk
- +44 29208 75554
- Abacws, Room 5.06, Senghennydd Road, Cathays, Cardiff, CF24 4AG

- Available for postgraduate supervision

## Overview

### Research interests

- Analysis of nonlinear partial differential equations
- Nonlinear viscoelasticity
- Strain-limiting theory of material response
- Gradient flows
- Solid mechanics
- Calculus of variations

### Research Groups

## Publication

### 2024

- Sengul, Y. 2024. A variational approach to frame-indifferent quasistatic viscoelasticity of rate type. Philosophical Transactions of the Royal Society of London Series A: Mathematical and Physical Sciences 382(2277), article number: 20230307. (10.1098/rsta.2023.0307)
- Erbay, H. A., Rajagopal, K. R., Saccomandi, G. and Şengül, Y. 2024. Dispersive transverse waves for a strain-limiting continuum model. Mathematics and Mechanics of Solids 29(6), pp. 1216-1227. (10.1177/10812865231188931)
- Rajagopal, K. R. and Sengul, Y. 2024. Solutions for the unsteady motion of porous elastic solids within the context of an implicit constitutive theory. International Journal of Non-Linear Mechanics 163, article number: 104728. (10.1016/j.ijnonlinmec.2024.104728)

### 2023

- Bachmann, L., De Anna, F., Schlomerkemper, A. and Şengül, Y. 2023. Existence of solutions for stress-rate type strain-limiting viscoelasticity in Gevrey spaces. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 381(2263), article number: 20220374. (10.1098/rsta.2022.0374)
- Duman, E. and Sengul, Y. 2023. Stress-rate-type strain-limiting models for solids resulting from implicit constitutive theory. Advances in Continuous and Discrete Models 2023(6) (10.1186/s13662-023-03751-x)
- Bachmann, L., Schlömerkemper, A. and Sengul, Y. 2023. A variational approach to strain-limiting viscoelasticity in one space dimension. Pure and Applied Functional Analysis

### 2022

- Bulicek, M., Patel, V., Suli, E. and Sengul, Y. 2022. Existence and uniqueness of global weak solutions to strain-limiting viscoelasticity with Dirichlet boundary data. SIAM Journal on Mathematical Analysis 54(6), pp. 6186-6222. (10.1137/21M1455322)
- Sengul, Y. 2022. Global existence of solutions for the one-dimensional response of viscoelastic solids within the context of strain-limiting theory. In: Espanol, M. et al. eds. Research in Mathematics of Materials Science., Vol. 31. Association for Women in Mathematics Series Springer, pp. 319-332.
- Goncharov, A. and Sengul, Y. 2022. Quasi-equivalence of bases in some Whitney spaces. Canadian Mathematical Bulletin 65(1), pp. 106-115. (10.4153/S0008439521000114)

### 2021

- Sengul, Y. 2021. One-dimensional strain-limiting viscoelasticity with an arctangent type nonlinearity. Applications in Engineering Science 7, article number: 100058. (10.1016/j.apples.2021.100058)
- Goncharov, A. and Sengul, Y. 2021. Logarithmic dimension and bases in Whitney spaces. Turkish Journal of Mathematics 45(4), pp. 1580-1591. (10.3906/mat-2009-30)
- Bulicek, M., Patel, V., Sengul, Y. and Suli, E. 2021. Existence of large-data global weak solutions to a model of a strain-limiting viscoelastic body. Communications on Pure and Applied Analysis 20(5), pp. 1931-1960. (10.3934/cpaa.2021053)
- Sengul, Y. 2021. Viscoelasticity with limiting strain. Discrete and Continuous Dynamical Systems - Series S 14(1), pp. 57-70. (10.3934/dcdss.2020330)
- Sengul, Y. 2021. Nonlinear viscoelasticity of strain rate type: an overview. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 477(2245), article number: 20200715. (10.1098/rspa.2020.0715)

### 2020

- Erbay, H. A., Erkip, A. and Sengul, Y. 2020. Local existence of solutions to the initial-value problem for one-dimensional strain-limiting viscoelasticity. Journal of Differential Equations 269(11), pp. 9720-9739. (10.1016/j.jde.2020.06.052)
- Erbay, H. A. and Sengul, Y. 2020. A thermodynamically consistent stress-rate type model of one-dimensional strain-limiting viscoelasticity. Zeitschrift für Angewandte Mathematik und Physik 71(3), article number: 94. (10.1007/s00033-020-01315-7)

### 2017

- Sengul, Y. and Vorotnikov, D. 2017. Generalized solutions for inextensible string equations. Journal of Differential Equations 262(6), pp. 3610-3641. (10.1016/j.jde.2016.11.040)

### 2015

- Erbay, H. A. and Sengul, Y. 2015. Traveling waves in one-dimensional non-linear models of strain-limiting viscoelasticity. International Journal of Non-Linear Mechanics 77, pp. 61-68. (10.1016/j.ijnonlinmec.2015.07.005)
- Ball, J. M. and Sengul, Y. 2015. Quasistatic nonlinear viscoelasticity and gradient flows. Journal of Dynamics and Differential Equations 27(3-4), pp. 405-442. (10.1007/s10884-014-9410-1)

### 2014

- Karagoz, A., Sengul, Y. and Basim, G. B. 2014. A Cahn-Hilliard modeling of metal oxide thin films for advanced CMP applications. ECS Transactions 61(17), pp. 15-20. (10.1149/06117.0015ecst)
- Mielke, A., Ortner, C. and Sengul, Y. 2014. An approach to nonlinear viscoelasticity via metric gradient flows. SIAM Journal on Mathematical Analysis 46(2), pp. 1317–1347. (10.1137/130927632)

### Articles

- Sengul, Y. 2024. A variational approach to frame-indifferent quasistatic viscoelasticity of rate type. Philosophical Transactions of the Royal Society of London Series A: Mathematical and Physical Sciences 382(2277), article number: 20230307. (10.1098/rsta.2023.0307)
- Erbay, H. A., Rajagopal, K. R., Saccomandi, G. and Şengül, Y. 2024. Dispersive transverse waves for a strain-limiting continuum model. Mathematics and Mechanics of Solids 29(6), pp. 1216-1227. (10.1177/10812865231188931)
- Rajagopal, K. R. and Sengul, Y. 2024. Solutions for the unsteady motion of porous elastic solids within the context of an implicit constitutive theory. International Journal of Non-Linear Mechanics 163, article number: 104728. (10.1016/j.ijnonlinmec.2024.104728)
- Bachmann, L., De Anna, F., Schlomerkemper, A. and Şengül, Y. 2023. Existence of solutions for stress-rate type strain-limiting viscoelasticity in Gevrey spaces. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 381(2263), article number: 20220374. (10.1098/rsta.2022.0374)
- Duman, E. and Sengul, Y. 2023. Stress-rate-type strain-limiting models for solids resulting from implicit constitutive theory. Advances in Continuous and Discrete Models 2023(6) (10.1186/s13662-023-03751-x)
- Bachmann, L., Schlömerkemper, A. and Sengul, Y. 2023. A variational approach to strain-limiting viscoelasticity in one space dimension. Pure and Applied Functional Analysis
- Bulicek, M., Patel, V., Suli, E. and Sengul, Y. 2022. Existence and uniqueness of global weak solutions to strain-limiting viscoelasticity with Dirichlet boundary data. SIAM Journal on Mathematical Analysis 54(6), pp. 6186-6222. (10.1137/21M1455322)
- Goncharov, A. and Sengul, Y. 2022. Quasi-equivalence of bases in some Whitney spaces. Canadian Mathematical Bulletin 65(1), pp. 106-115. (10.4153/S0008439521000114)
- Sengul, Y. 2021. One-dimensional strain-limiting viscoelasticity with an arctangent type nonlinearity. Applications in Engineering Science 7, article number: 100058. (10.1016/j.apples.2021.100058)
- Goncharov, A. and Sengul, Y. 2021. Logarithmic dimension and bases in Whitney spaces. Turkish Journal of Mathematics 45(4), pp. 1580-1591. (10.3906/mat-2009-30)
- Bulicek, M., Patel, V., Sengul, Y. and Suli, E. 2021. Existence of large-data global weak solutions to a model of a strain-limiting viscoelastic body. Communications on Pure and Applied Analysis 20(5), pp. 1931-1960. (10.3934/cpaa.2021053)
- Sengul, Y. 2021. Viscoelasticity with limiting strain. Discrete and Continuous Dynamical Systems - Series S 14(1), pp. 57-70. (10.3934/dcdss.2020330)
- Sengul, Y. 2021. Nonlinear viscoelasticity of strain rate type: an overview. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 477(2245), article number: 20200715. (10.1098/rspa.2020.0715)
- Erbay, H. A., Erkip, A. and Sengul, Y. 2020. Local existence of solutions to the initial-value problem for one-dimensional strain-limiting viscoelasticity. Journal of Differential Equations 269(11), pp. 9720-9739. (10.1016/j.jde.2020.06.052)
- Erbay, H. A. and Sengul, Y. 2020. A thermodynamically consistent stress-rate type model of one-dimensional strain-limiting viscoelasticity. Zeitschrift für Angewandte Mathematik und Physik 71(3), article number: 94. (10.1007/s00033-020-01315-7)
- Sengul, Y. and Vorotnikov, D. 2017. Generalized solutions for inextensible string equations. Journal of Differential Equations 262(6), pp. 3610-3641. (10.1016/j.jde.2016.11.040)
- Erbay, H. A. and Sengul, Y. 2015. Traveling waves in one-dimensional non-linear models of strain-limiting viscoelasticity. International Journal of Non-Linear Mechanics 77, pp. 61-68. (10.1016/j.ijnonlinmec.2015.07.005)
- Ball, J. M. and Sengul, Y. 2015. Quasistatic nonlinear viscoelasticity and gradient flows. Journal of Dynamics and Differential Equations 27(3-4), pp. 405-442. (10.1007/s10884-014-9410-1)
- Karagoz, A., Sengul, Y. and Basim, G. B. 2014. A Cahn-Hilliard modeling of metal oxide thin films for advanced CMP applications. ECS Transactions 61(17), pp. 15-20. (10.1149/06117.0015ecst)
- Mielke, A., Ortner, C. and Sengul, Y. 2014. An approach to nonlinear viscoelasticity via metric gradient flows. SIAM Journal on Mathematical Analysis 46(2), pp. 1317–1347. (10.1137/130927632)

### Book sections

- Sengul, Y. 2022. Global existence of solutions for the one-dimensional response of viscoelastic solids within the context of strain-limiting theory. In: Espanol, M. et al. eds. Research in Mathematics of Materials Science., Vol. 31. Association for Women in Mathematics Series Springer, pp. 319-332.

## Research

My research, in the most general terms, is on the analysis of nonlinear partial differential equations and its applications in material science and engineering. More specifically, I am interested in the modelling of material response from a classical point of view as well as using the recently developed implicit constitutive theory. I am also interested in the theory of gradient flows, infinite-dimensional dynamical systems, and calculus of variations.

### Funding

- Heilbronn Small Grant (2022 - 2023)
- Cardiff - Illinois Collaborative Fund Award (2024)
- Taith Funding (incoming - Turkey)(2024)
- INI Retreat (2024)
- Taith Funding (incoming - USA)(2025)
- London Mathematical Society Scheme 5 Grant (2025)

## Teaching

- I am a Fellow of the Higher Education Academy (FHEA)
- I am a STEM Ambassador.

I teach:

- Finite Elasticity
- Calculus of Variations
- Theoretical Fluid Dynamics

## Biography

Dr. Şengül Tezel received her B.Sc. and M.S. degrees in 2005 and 2006, respectively, from the Department of Mathematics in Bilkent University, Turkey. She completed her D.Phil. in Mathematics at the Mathematical Institute in the University of Oxford, UK. She worked as a post-doctoral researcher between 2010 and 2011 in the University of Coimbra, Portugal. After working in the Department of Natural and Mathematical Sciences at Özyeğin University, Turkey, and Faculty of Engineering and Natural Sciences at Sabancı University, Turkey, she joined Cardiff University, School of Mathematics in October 2021.

## Supervisions

**Rabin Poudel**(2022 - Present): Mathematics of liquid crystal elastomers- (Co-supervisor)
**Luisa Bachmann,**University of Wurzburg (2021 - Present): A variational approach to the evolution of strain-limiting viscoelasticity

### Current supervision

## Rabin Poudel

Research student