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Mechanics under the Fold: How Origami Creates Sophisticated Mechanical Properties

Abstract: ​Origami, the ancient Japanese art of paper folding, is not only an inspiring technique to create sophisticated shapes, but also a surprisingly powerful method to induce nonlinear mechanical properties. Over the last decade, advances in crease design, mechanics modeling, and scalable fabrication have fostered the rapid emergence of architected origami structure and material systems. They typically consist of folded origami sheets or modules with intricate three-dimensional geometries, and feature many unique and desirable mechanical properties like auxetics, tunable nonlinear stiffness, multi-stability, and impact absorption. Rich designs in origami offer great freedom to prescribe the performance of such origami structures and materials. In addition, folding offers a unique opportunity of fabrication at vastly different sizes. This talk will highlight our recent studies on the different aspects of origami-based structures and materials–geometric design, mechanics analysis, and achieved properties–and discusses the challenges ahead.

Bio Sketch: Dr. Suyi Li is an assistant professor of mechanical engineering at the Clemson University. He received his Ph.D. at University of Michigan in 2014. After spending two additional years at Michigan as a postdoctoral research fellow, he moved to Clemson in 2016 and established a research group on dynamic matters. His technical interests are in origami-inspired adaptive structures, multi-functional mechanical metamaterials, and bio-inspired robotics. Within his first three years at Clemson, Dr. Li has secured more than one million dollars of research funding, including the prestigious NSF CAREER award. His paper on fluidic origami received the Best Paper Award by the ASME Branch of Adaptive Structures and Material Systems.

Active Thermosyphons to Condense Water from Power Plant Flue Gas, and an Overview of Energy Research at Stony Brook University

The talk will focus on two themes.  The first will be an overview of our current ARPA-E project to condense water from flue gas for dry-cooled power plants power plants. Water use by power plants is an increasing concern across the U.S., and is particularly problematic in arid regions, such as the southwest.  In this project, an advanced two-phase thermosyphon concept is employed that removes several of the traditional limitations of conventional thermosyphons. The condensed water can be used to pre-cool the condenser air to reduce the effective ambient temperature, for turbine inlet air evaporative cooling, or for other uses in the plant, as needed. The second portion of the talk will provide a short overview of other energy-related research activities in the Mechanical Engineering department at Stony Brook University with the goal to explore future opportunities for collaboration and joint projects between both institutions.

Bio: Jon Longtin joined the Mechanical Engineering Faculty at Stony Brook University in 1996. He came to Stony Brook after receiving his Ph.D. degree in 1995 from U.C. Berkeley, followed by a one-year postdoc at the Tokyo Institute of Technology in Japan. His research interests include energy conservation, innovative energy transfer and storage, and energy monitoring and diagnostics, as well as laser materials processing, particularly with ultrafast lasers and the development of sensors for harsh environments. His research has been funded by NSF, DOE, DOD, NASA, NYSERDA, and a variety of industrial sources.  He is the author of over 140 technical publications and holds 11 issued and pending patents. He has received the Presidential Early Career Award for Scientists and Engineers, two Excellence in Teaching Awards, and an R&D 100 award.  He is a licensed Professional Engineer in New York State and serves as a technical advisor to a variety of companies and non-profit organizations.

Molecular simulations of mechanical properties for polymer materials

The U.S. Army Research Laboratory (ARL) was activated 25 years ago with a mission to discover, innovate and transition science and technology to ensure dominant strategic land power. One of key research strategies at ARL is a development of superior protection systems for individual warfigter and vehicles. The protective systems often use polymers due to their low weight, good strength and toughness which improves resistance to ballistic penetration.

In this presentation, we will review fundamental research projects carried out at ARL and aimed at understanding and prediction of mechanical properties for polymers at high strain rates. We will focus on semicrystalline polyethylene discussing  onset of crystallization in polymer melt upon drawing and cooling. Our model includes amorphous domains, explains experimentally known mechanics and supports fracture mechanism through chain pulling. We will discuss shock propagation in anisotropic semicrystalline models at atomistic level.

We also study emerging 2D polymers inspired by Kevlar(R) which is well known for its remarkable strength and stiffness facilitated by the hydrogen bonds formed between Kevlar chains. Molecular and micromechanical calculations predict that ensembles of 2D molecules bonded with hydrogen bonds will form stiff, strong and tough films of unprecedented mechanical performance.

Bio: Dr.  Jan Andzelm serves as the Team Leader of the Multiscale Modeling Team in the Polymer Branch at ARL investigating properties of materials important for Soldier protection. The team is developing and applying novel computational techniques at quantum mechanical, atomistic and mesoscale levels aimed at understanding and predicting structural, mechanical and electronic properties of macromolecules and composite materials.

Dr. Andzelm has co-authored over 140 scientific papers and book contributions that attracted more than 14000 citations and generated h-index of 42. Dr. Andzelm was selected as a U.S. Army Research Laboratory Fellow in 2010.

Profs. Chen and Norato win coveted 2018 NSF CAREER awards for their work on Additive Manufacturing and Topology Optimization

Two ME professors received the 2018 National Science Foundation’s CAREER award, which is the Foundation’s most prestigious award in support of early-career faculty.

Prof. Xu Chen’s award will support his research on thermal modeling, sensing, and controls to enable new generations of powder bed fusion (PBF) additive manufacturing. In contrast to conventional machining, where parts are made by cutting away unwanted material, additive manufacturing — also called 3D printing — builds three-dimensional objects of unprecedented complexity by progressively adding small amounts of material. PBF is a popular form of AM for fabricating complex metallic or high-performance polymer parts. This CAREER project will create new knowledge critical for substantially higher accuracy and greater reproducibility in PBF and AM. Building on innovations to model and control the thermal mechanical process, the research will illuminate ways to mitigate quality variations on the fly, and provide new feedback-centric control paradigms to engineer the layered deposition of thermal energy, which is imperative for quality and reproducibility. PBF parts are increasingly preferred in applications ranging from advanced jet-engine components to custom-designed medical implants. The outcomes of this project will facilitate fabrication of products to benefit the US economy and improve quality of life. More broadly, methods and tools developed from this research has the potential to drastically impact the manufacturing of a wide range of components for the energy, aerospace, automotive, healthcare, and biomedical industries that can benefit from short-run high-quality production.

Prof. Norato’s award will support fundamental research to formulate a design framework to systematically incorporate geometric design rules and manufacturing cost considerations into the computational design of structures. In particular, the techniques advanced in this project belong to a group of techniques called topology optimization, in which a computer program finds the optimal shape of a structural component or an architected material. This research will enable the conceptual design and optimization of lightweight, high-performance, and economically-viable structures with applications across a wide range of engineering industries. The new design capabilities will have the potential to significantly reduce manufacturing and R&D costs and thereby increase the economic competitiveness of American manufacturers. Prof. Norato is also a recipient of the 2017 ONR Young Investigator Award.

Both awards are for five years and approximately $500,000 (minimum), and have an outreach component towards K-12 students and people from underrepresented communities.

Atomistic Modeling at Experimental Strain Rates and Time Scales

Abstract: I will present a new computational approach that couples a recently  developed potential energy surface exploration technique with applied mechanical loading to study the deformation of atomistic systems at strain rates that are much slower, i.e. experimentally-relevant, as compared to classical molecular dynamics simulations, and at time scales on the order of seconds or longer.  I will highlight the capabilities of the new approach via multiple examples, including:  (1) Providing new insights into the plasticity of amorphous solids, with a particular emphasis on how the shear transformation zone characteristics, which are the amorphous analog to dislocations in crystalline solids, undergo a transition that is strain-rate and temperature-dependent; (2) Demonstrating new, strain-rate-dependent yield mechanisms and phenomena in bicrystalline metal nanowires; (3) Demonstrating new mechanical force-induced unfolding pathways for the protein ubiquitin.

Biographical Sketch: Harold Park is a Professor of Mechanical Engineering at Boston University. He received his BS, MS and PhD in Mechanical Engineering from Northwestern University in 1999, 2001 and 2004, respectively.  He was a postdoctoral researcher at Sandia Labs (California) from 2004-2005.  He held tenure-track positions at Vanderbilt University (2005-2007) and the University of Colorado (2007-2009) before moving to Boston University in 2010.  His research has generally focused on the mechanics of nanostructures, coupled physics phenomena at nano and continuum length scales, and the mechanics of soft, active materials.

 

What’s at Stake for Apple in iPhone Legal Case

Enter passcode screen of an iPhone running iOS 9

By Colin Poitras– UConn Communications

This story originally appeared in UConn Today.

In what some are calling the most important technology case of the decade, the FBI has obtained a court order compelling tech giant Apple to develop special software that will allow them to bypass security measures and unlock an iPhone belonging to one of the shooters in the San Bernardino mass shooting last December.

But Apple CEO Tim Cook is refusing to comply. Cook says the government’s request would force Apple to “hack our own users and undermine decades of security advancements that protect our customers.” The case has become the focus of a national debate pitting the government’s interest in protecting national security against the fundamental rights of companies and civilians to conduct their business without government intrusion.

Apple has until Feb. 26 to file its formal objections in court.

With the case continuing to capture daily headlines, UConn Today discusses the technical issues underlying the case with associate professor of computer science and engineering Laurent Michel. Michel is co-director of the Comcast Center of Excellence for Security Innovation at UConn, an advanced cybersecurity lab.

  1. What is behind Apple’s resistance to providing the federal government with modified software – a so-called backdoor – that would allow investigators to break into one of their phones?
  2. Once you modify software to create a backdoor, it can be used not only by the government on this specific phone but it could be used on other Apple devices as well. It can also be exploited by others, including the authors of malware. The moment you create a backdoor, even if it is with good intentions, it has the potential of being exploited. The government is downplaying the risks, and their argument rests on the stipulation that the software will be developed in such a way it will work on this one iPhone only. To do that, Apple would need to digitally sign the software to make it harder to break the tie-in. Yet Apple’s signing process is highly secure. The master key used for signing an Apple operating system or iOS is a key asset for the company that is highly protected and rarely used. If those keys were leaked or compromised as the result of a request like this, that would have dramatic implications. Apple also rightly insists on signing code that only meets specific quality standards. Here, it would be signing code with a deliberate vulnerability that could be exploited. This sets a dangerous precedent.
  3. The federal government has offered to allow Apple to immediately destroy the new software once the investigation is complete. But Apple has indicated that course of action isn’t enough. Why is that?
  4. Even if they say they will destroy it, it is a digital artifact. It is a piece of software. The moment that there is a weakness that is introduced in the device, it sets a terrible precedent. It sets the stage allowing anyone to recreate the same thing. If it’s been done once, it can be done again. Once software like this is created, what is stopping the government from making more and more requests of this type to technology companies?
  5. It’s been reported that Apple has cooperated with law enforcement on numerous investigations before and helped them break into suspects’ phones. What is it about this case that has become a line in the sand?
  6. Because Apple has changed their operating system. With earlier versions of Apple’s iOS operating system, it was much easier to recover information compared to this version. Starting with iOS7, Apple has made it, even for themselves, very difficult – without creating such a backdoor – to get into a device and recover encrypted data. Apple is taking the privacy of their customers very seriously. In this case, the FBI’s request includes three things. 1. The software would allow them to bypass the phone’s security measures so they could obtain the password. 2. The backdoor would remove any limits on the number of password attempts and would eliminate the delay one experiences when entering the wrong password. 3. Finally, the software would be tied strictly to the device they are breaking into. But again, it is a software attack and software can be changed. Once you have created the opportunity, the potential for repeating it and having an open backdoor is what makes Apple so uncomfortable.
  7. All things Apple aside, you’re an expert, what can people do to protect their personal information from hackers and others trying to access their data without permission?
  8. The smart devices that started appearing on the market a few years ago, like wearable electronics and smart phones, are commodity devices. They are not PCs where you have control and can increase the security of your system. There are well-known commercial solutions for PCs to encrypt your email and the files on your hard drive. But once you move your data to a commodity device, like a smart phone or a smartwatch, you cannot tinker with it. You have surrendered the protection of your data to the manufacturer, and have to trust them to take the proper steps to keep your data secure. It’s a delegation of trust. The moment the industry feels it has no choice and is compelled to create these backdoors, you must assume that whatever is on those devices is potentially public data. These days, many people replicate their data on multiple devices and storage solutions (e.g. the cloud). Some of those domains may be secure and some may not be. It is advisable to keep track of where each piece of sensitive data is held and replicated and what protection it enjoys in each case.

Published: February 26, 2016

ME Curriculum Quick Tips

ME Curriculum Quick Tips

General Education Requirement

All six courses for Content Areas 1, 2, and 3 must be from different academic departments/units. For Content Area 4, two courses are required. These two courses may be from the same department. One can be double counted (+) from Content Area 1 or 2. One must be an international course (I). (More information on the General Education Requirement)

Mechanical Engineering Requirement

9 credits in 2000 level or higher ME Courses which are not used to satisfy any other requirement. (More information on the Mechanical Engineering Requirement)

Professional Requirement

This requirement is met by 6 credits in 2000 level or higher courses in any Engineering department or from Mathematics, Statistics, Physical and Life Sciences as listed in the UConn Undergraduate Catalog.

W Requirement

All ME students are required to take two writing (W) courses, i.e., ME 4973W plus one other before graduation. (See the UConn Undergraduate Catalog under “Academic Regulations”).

Math or Science Requirement

6 credits in 1000 (100) or higher level Mathematics, Statistics, Physical and Life Sciences as listed in the UConn Catalog meet this requirement. Courses at the 2000 level can also be used to meet the Professional Requirement. Some restrictions apply. (More information on the Math or Science Requirement)

Language Requirement

To satisfy the language requirement, a student has to present either 3 years intermediate level of one foreign language (high school) or 2 semesters (college) of one foreign language.

Mechanical Engineering Electives

9 credits in 3000 (200) level or higher Mechanical Engineering courses which are not used to satisfy any other requirement. No more than one ME 3999 course may be used toward meeting this requirement. This course work may also be applied towards a minor.

Free Electives

Any course meets this requirement except those listed under restrictions in the UConn Undergraduate Catalog – Engineering Section.

Plan of Study

Each student must complete a Plan of Study form in the first semester of the junior year. Plan of Study forms detail how a student will meet curricular requirements.

ME Curriculum Tips continued

Bottleneck Course

Bottleneck courses are prerequisites to other courses. Students should pay extra attention to these courses when considering their curricular plan as a delayed bottleneck course can affect the graduation date. Example bottleneck courses are ME 2233, ME 3250, CE 2120, and CE 3110. The ME Curriculum Map in the ME Course can be used to identify bottleneck courses.

Undergraduate Transfer Admission

Undergraduate Admissions offers a list of UConn equivalencies of courses transferred from 35 colleges/universities in Connecticut.

ME Areas of Concentration (optional)

Students may choose to focus their 3 required ME electives (taken in the Junior/Senior years) in one Area of Concentration: 1) Aerospace, 2) Dynamic Systems and Control, 3) Energy and Power, 4) Design and Manufacturing. (More information on the ME Areas of Concentration)

Double Major (optional)

The requirements of the home department of each major will determine double major requirements. Generally, the number of credits should satisfy both majors. The student must meet the requirements of both, but will not need 128+128=256 credits because many courses can be counted for both majors. A separate Plan of Study form must be prepared and submitted for approval to each department.

Double Degree (optional)

Students may earn two separate bachelor degrees from two different schools or colleges of the University. Students must meet the requirements of both schools/colleges, and a Plan of Study form must be submitted to each department for each degree.

Minor (optional)

15 credits are needed in order to qualify for a minor. However, a minor in Materials Science & Engineering requires 16 credits due to a one-credit lab course. Math Minor (optional) In addition to the 2 Math courses (Math 1132Q and 2211) listed in ME Requirements, three additional courses (9 credits) are necessary for a math minor. Please read the UConn Undergraduate Catalog “Minors – Mathematics” for details. (Note: “Pass/Fail” is not allowed except for credits beyond 128).