ENAC Semester Project Final Presentation Presenter Qimin Wang - PowerPoint PPT Presentation

ENAC Semester Project Final Presentation Presenter Qimin Wang Supervisor Prof. Molinari Jean-François Dr. Nicolas Richard Dr. Roozbeh Rezakhani

Mýrdalsjökull Glacier, Iceland Photo by Qimin Wang

CONTENTS Ⅰ INTRODUCTION Ⅱ PREVIOUS WORK UPDATED RESULTS Ⅲ CONCLUSIONS Ⅳ ENAC Semester Project Final Presentation ENAC Semester Project Mid-term presentation

Ⅰ INTRODUCTION Date Source Ø Data of the Bowdoin glacier calving in 2017 from Eef Van Dongen, ETH Zurich Project Goal Ø Viscous behavior on long time scale Ø Elastic behavior on short time scale Background Ø Ice calving “the breaking of ice chunks from the edge of a glacier” ——Essentials of Geology, 3rd edition ENAC Semester Project Final Presentation

Ⅰ INTRODUCTION Bowdoin Glacier Calving in July 2017 Picture from Eef Van Dongen ENAC Semester Project Final Presentation

Ⅰ INTRODUCTION Ø Cause of Ice calving: 1 st , 2 nd , and 3 rd order processes Longitudinal stretching is the 1 st order process. friction longitudinal glacier geometry stretching Iceberg water pressure Sea Base ENAC Semester Project Final Presentation

Ⅰ INTRODUCTION Calving events resulting from various geometries Tabular icebergs Break-off + rotation if width < thickness if width > thickness Picture from Dr. Eef ENAC Semester Project Final Presentation

Ⅰ INTRODUCTION Calving events resulting from different water conditions Water-free crevasses Water- filled crevasses trigger small calving trigger large calving Picture from Dr. Eef ENAC Semester Project Final Presentation

Ⅱ INTRODUCTION Data Structure Data fracture radarVelocity Meshfiles tides satVelocity From 4/7/2017 to 8/7/2017 ENAC Semester Project Final Presentation

Ⅱ DATA & SIMULATION Ø Meshfiles of different resolutions 10 m with crack 10 m 20 m ENAC Semester Project Final Presentation

Ⅱ DATA & SIMULATION Ø Mesh for currency study side3 top side4 An enormous chocolate bar! 3.23 km in length 1.04 km in width 352 m in height side2: waterfront 3:1:0.3 Resolution: 20m bottom side1 Nodes: 53,523 ENAC Semester Project Final Presentation

Ⅱ DATA & SIMULATION Ø radarVelocity/ satVelocity Velocity at the top surface: derived from rader interferometry Body velocity: solved by the Navier-Stokes equations excluding acceleration ENAC Semester Project Final Presentation

The CONTENTS Ⅰ INTRODUCTION Ⅱ PREVIOUS WORK UPDATED RESULTS Ⅲ FUTURE PLAN Ⅳ ENAC Semester Project Final Presentation ENAC Semester Project Mid-term presentation

Ⅲ UPDATED RESULT Ø Boundary conditions Surface velocity Ø Initial Conditions Body velocity g Water pressure ENAC Semester Project Final Presentation

Ⅳ PREVIOUS WORK o Understood the provided data o Learned how to use Akantu and Fidis o Coded for basic explicit simulation ENAC Semester Project Final Presentation

Ⅳ PREVIOUS WORK Ø Future work o Review our goals o Viscous behavior on long time scale o Elastic behavior on short time scale o Tides impact (i.e., how to apply time-dependent boundary condition) o Crack and the water pressure behind o Glacier elevation o Implicit integration methods ENAC Semester Project Final Presentation

Ø tides 4 July 8 July ENAC Semester Project Final Presentation

The CONTENTS Ⅰ INTRODUCTION Ⅱ PREVIOUS WORK UPDATED RESULTS Ⅲ CONCLUSION Ⅳ ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT o Tested and optimized parallel computing setup o Coded for time-dependent B.C. o Coded for mesh coordinates translation o Studied the impact of how to apply B.C.s o Redefined the simulation steps o Considered the material damage ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT Ø Distributed mesh for HPC ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT • Impact of how to apply B.C.s 10 %& 𝑛/𝑡 10 # 𝑂 ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT Ø Loading profiles for the water pressure Factor of water pressure Time/s 3s 10s 30s ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT These loading profiles do not change the maximum Ø Kinetic Energy Variation of the kinetic energy ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT ≈ log 10 34 log 𝐹 0 Ø Comparison of Kinetic Energy and Potential Energy 10 45 = 7 𝐹 1 ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT Ø Propagation of stress wave ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT Ø Modified simulation scheme 1. Static step: balanced water pressure with deformation 2. Explicit step: long-term effect of velocity ENAC Semester Project Final Presentation

Ⅱ DATA & SIMULATION Ø Material damage Mazars model: A behavioral model to represent damage evolution in concrete. The damage is directly evaluated from the strain ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT Ø System Energy Variation ENAC Semester Project Final Presentation

Ⅲ UPDATED RESULT Ø Damage propagation t = 55 s t = 65 s Causes: Fixed B.C. • Coarse mesh • t = 75s ENAC Semester Project Final Presentation

The CONTENTS Ⅰ INTRODUCTION Ⅱ PREVIOUS WORK UPDATED RESULTS Ⅲ CONCLUSION Ⅳ ENAC Semester Project Final Presentation ENAC Semester Project Mid-term presentation

Ⅳ CONCLUSION What have been done? • The basic workflow using Akantu for HPC • Relationship between loadings and system energy • Simulation scheme and simulation acceleration • Damage initiation and propagation ENAC Semester Project Final Presentation

Ⅳ CONCLUSION Future work: • Redesign the simulation scheme and B.C.s • Test the proper material damage models • Use weaker material around the crack propagation region • Simulate with finer mesh Crack detail in the finer mesh. ENAC Semester Project Final Presentation

Thank you for your attention! ENAC Semester Project Final Presentation