fracture mechanics

Hi my name is Karla Polivka. I am working part-time on my PhD degree in Mechanical Engineering at the University of Nebraska-Lincoln (UNL). What I mean by part-time is that I have been taking one class a semester for the last 5 semesters. I also received my Bachelors and Masters degrees in Mechanical Engineering from UNL.

I'm Xuanhe Zhao, a first year PhD student working in Suo's Group, at Harvard University. Prior to coming to Harvard, I obtained a Master Degree in Materials Engineering from University of British Columbia.

My name is J. Alberto Ortega, and I am a PhD student in civil engineering at the Massachusetts Institute of Technology (MIT). My undergraduate education took place in Texas A&M University (I am a proud member of the Fightin’ Texas Aggie Class of 2002, WHOOP!), majoring in Structural Engineering. I recently obtained my Master of Science degree in Structures and Materials from MIT.

    I am Ashwani Kumar Goel, currently pursuing my Ph.D. from Engineering Mechanics Department, University of Nebraska Lincoln. I am from India. I have taken my Bachelors degree in Mechanical Engineering from HBTI, Kanpur,India and my Masters degree in Applied Mechanics from IIT, Delhi, India. I have taken lots of courses related to solid mechanics starting from my undergraduation. I have taken strength of materials ,applied mechanics, mechanics of solids during my undergraduate degree and applied elasticity, theory of plasticity, theory of plates and shells, continuum mechanics, linear viscoelasticity during my graduate degree. The group I work in focuses on theoretical, computational and experimental methods for the modeling and analysis of materials and the simulation of their response. I have been part of this group for about two and half years and focusing on theoretical and computational methods to extract material characteristics from novel experimental methods and in the implementation of these characteristics into simulations.

My name is Adrian Podpirka and I am a first year graduate student at Harvard studying Applied Physics. My undergraduate major was material science and engineering at Columbia University. Before taking fracture mechanics this semester I have taken Solid Mechanis (ES 240) with professor Suo.

Hi all,My name is Emmeline Lemos, I am a current Master student in Civil Engineering at University of Nebraska-Lincoln. I took my bachelor degree in Civil Engineering at my home country-Brazil. When I decided to leave my country and to come to graduate school,  I came with the great desire to learn more, and to try to absorb as much as possible from teachers, classmates and this new world that I'm surround by. Definitely, this desire to learn is one of my strengths and makes me overcome the challenges.  

As can be seen from my previous and current degree, most of my background is in Civil Engineering which give me not so much knowledge in Mechanics and been one of my weakness. But, Fracture Mechanics is not the first class that I’m taking in this field; I already took FEM and Continuum Mechanics.

My name is Jeff Chambers, I am a 1st year PhD candidate in the Department Aeronautics and Astronautics at MIT. I received my BS in Mechanical Engineering from the University of California, Santa Barbara. While at UCSB, I worked with Prof. Keith Kedward investigating impact of composites. I did my MS in Aero/Astro at MIT working with Prof. Brian Wardle on durability of structural health monitoring systems. My PhD project is investigating failure theories for traditional composites. I will be working with Prof. Paul Lagace. My research lab is the Technology Laboratory for Advanced Materials and Structures (TELAMS).

Lecture 7.  Stability of large scale yielding crack growth & fracture mechanisms

I am Nitin Sharma, enrolled as M.S. student in Mechanical Engg. at UNL. I did my B.Tech in Mechanical Engg. in India. Worked as an Application Engineer in CAE, for some years, before deciding to take sabbatical and head back to school. Other courses that I have taken in solid mechanics include Mechanics of Materials and Mechanics of Composite Materials (currently enrolled). I feel that my experience with Finite Element codes would help me simulate crack propogation numerically. However, coming back to school after a long time makes me little out of touch with some mathematical concepts.

My name is Ling Zhu and I am currently a PhD student in Mechanical Engineering of University of Nebraska Lincoln. I got my bachelor degree in Civil Engineering from Nanjing University of Science and Technology, China and master degree in Engineering Mechanics from Zhejiang University, China. The research group I am now in is called Midwest Roadside Safety Facility ( mwrsf.unl.edu ) and I am doing the research of simulation of material failure. We are using nonlinear FE software LS-DYNA to simulate the design before performing real-life physical test to reduce the cost.

Point by point, here's the goods:

• I am currently enrolled at the University of Nebraska-Lincoln.
• Prior mechanics courses include: Mechanics of Materials, Advanced Mechanics of Materials, and I'm currently taking Mechanics of Composite Materials
• I received my Undergraduate degree in Civil Engineering from the University of Nebraska Lincoln.
• My strengths for this class...
  

My name is Jamilla Lutif. I am up to finish my Master in the Civil Engineering Department at UNL. My BS degree is also in Civil Engineering, and I got the BS degree at the Universidade federal do Ceara, in Brazil.

Dear all:

Please post your self-introduction online, following the instruction, but turn in the rest of your homework on paper to your teaching assistants.

Students from Harvard and MIT turn in homework to
Zhen Zhang, (617)-384-7894, zhangz@deas.harvard.edu, Pierce Hall 406, Skype: flyinskypku.

My name is Nanshu Lu. I am a second year doctoral student in the Suo group at Harvard Engineering and Applied Science.

I obtained my B.S. in Solid Mechanics from the Department of Engineering Mechanics at Tsinghua University, China. You can see my resume here.

My course background includes Strength of Materials, Continuum Mechanics and Fundamental Elasticity taken at Tsinghua University and graduate level Elastisity (ES 240) taught by Prof. J. Rice, Deformation of Solids (APY 293) taught by Prof. F. Spaepen, Fracture (ES 247) and Plasticity (ES 246) taught by Prof. J. Vlassak and Zhigang's another course Advanced Elasticity (ES 241) this semester here at Harvard.

My first teaching experience was TFing Zhigang's ES 240 last semester.

Although I think I've indulged in a systematic cognition of solid mechanics with somewhat solid understanding of this subject, I sometimes do lack a spirit of digesting materials and making them my own. It indeed has occured to me that having a hard time to fish out the proper solution to a novel problem although I've owned all the needed tools and skills. Under the instruction of John and Zhigang I hope I will make the transformation from a student learner to a scholar learner.

Nonlinear fracture mechanics joints main parts of solid mechanics: fracture, elasticity and plasticity, the essential foundation to my research interests of mechanics in thin films, both theories and experiments. One of my subject is about chip packaging interaction. It is well known that nowadays a typical electronic package assembly consists of different materials which are attached together in a variety of ways. No other course will be more proper for this subject than this "Fracture mechanics of thin films and composit materials". Though I've read literatures specialized on thin film debonding I believe taking this course is the most efficient way for me to have profound and comprehensive understanding of fracture mechanics as a whole.

I am Namiko Yamamoto, a 1st year PhD student in Aero/Astro department at MIT. I have been Aero/Astro major for both my BS and MS at MIT, also. I have taken ES240 (solid mechanics) with Prof. Suo this past fall, and have taken one solid mechanics class (2.071) at MIT. This is my first time learning about fracture mechanics. My weakness is that I don't know the material well, and even now I need to spend good time to understand the materials given in the lecture (notes and lectures are so helpful). My strength will be my motivation to learn the materials. It has been much fun in the class, and this learning will help me much in my research. For my PhD, I will be studying how to strengthen structural composites with carbon nanotubes (CNTs) under Professor Brian Wardle. In the current design, we will be investigating delamination fractures between prepregs. This class will be so helpful for this research, and further since I want to continue studying in materials/structure field beyong PhD.

Hi, I am Roberto Soares and I am a PhD student in Engineering Mechanics at UNL. My undergrad is from Brazil in Civil Engineering (Federal University of Ceara) and my Master’s in Engineering Mechanics from UNL. In the past I had the chance to take Continuum Mechanics, Adv Mechanics of Materials, FEM and several courses in Materials.

Hi everyone. My name is Michael Mahoney and I'm currently enrolled in the fracture mechanics course at the University of Nebraska. I am pursuing my master's degree in engineering mechanics. My advisor is Dr. Joseph A. Turner and my research is in acoustoelastic methods for characterizing stress in a material. Here is a link to our research group:  http://em-jaturner.unl.edu/.

I am currently enrolled at University of Nebraska-Lincoln. The main courses I've taken in Solid Mechanics are Continuum Mechanics and Advanced Finite Element Method (currently taking). My undergraduate and Master major is Civil Engineering, both obtained in my home country Brazil. I would say that my strength related to this course is my motivation to understand the complex physical process of cracking, and my weakness is probably the fact that I don't have a good background in Fracture Mechanics. I am curretly pursuing my PhD at UNL under supervision of Dr. David Allen. Unfortunately our group doesn't have a published website. I am currently working on the development of a multi-scale computational model for predicting the evolution of damage in composites subject to impact loading. So, a better understanding of fracture mechanics and of the physical process underlying cracking will be of major importance to my research work. Finally, as fracture mechanics is present in any engineering application, I am sure it will greatly improve my education in a general basis.

• Various cracks in thin films under tensile or compressive stresses
• Micrographs of cracks in thin films
• A micrograph of a channel crack
• The origin of stress in a film
• Stress in a thin film due to mismatch in the coefficients of thermal expansion
• Stress in film due to bending
• Measure redisual stress using wafer curvature
• Channel crack:  initiation vs. steady propagation
• Steady-state energy release rate of a channel crack
• Channel crack in patterned structure

Lecture 5

Lecture 5

Lecture 4

        I'm Francisco Thiago S. Aragao. Please call me Thiago. I'm currently enrolled at the University of Nebraska at Lincoln Civil Enginering Master's Program under the advisory of Dr. Yong-Rak Kim. I have also a minor course in Engineering Mechanics. Below I'm answering the questions from the Problem 1 of Fracture Mechanics' Assignment 1.

Prior courses in solid mechanics: