Yuhang Hu's blog

A few updates about the ASME IMECE 2020 Mechanics of Soft Materials symposium:

•            IMECE 2020 will be fully online with the technical meetings held during the week of November 15. IMECE remains the same otherwise. The online format will leverage the extra capabilities that come from a virtual setting.

•            Authors will still be required to register to present and to be included in the final program. Registration will be at a reduced rate (exact amount to be announced).

Dear Colleagues,

We would like to cordially invite you to submit an abstract to our symposium titled “Smart Hydrogels and Living Materials” as part of the 2018 Spring MRS conference  that will be held in April 2-6, 2018 in Phoenix, Arizona.

The deadline for abstract submission is Oct. 31st, 2017.

Dear Colleagues and Friends,

The departments of Mechanical Science and Engineering and Civil and Environmental Engineeing at University of Illinois Urbana Champaign will be cohosting the first Midwest Mechanics of Materials and Structures workshop at UIUC this Summer (Aug. 26th, 2015).

Symposium Title: “Mechanics & Physics of Soft Materials”

Organizers: Oscar Lopez-Pamies, Xuanhe Zhao, Yuhang Hu & Stephan Rudykh

Sessions: 4

Symposium Title: “Mechanical Characterization of Soft Materials”

Organizers: Shengqiang Cai (shqcai@ucsd.edu) & Yuhang Hu (yuhanghu@illinois.edu)

Sessions: 2

Abstract:

Mechanical characterization of soft hydrated materials

By Yuhang Hu, University of Illinois at Urbana Champaign

Importance

We develop a method of poroelastic relaxation indentation (PRI) to characterize thin layers of gels.  The solution to the time-dependent boundary-value problem is obtained in a remarkably simple form, so that the force-relaxation curve obtained by indenting a gel readily determines all the poroelastic constants of the gel—the shear modulus, Poisson’s ratio, and the effective diffusivity.  The method is demonstrated with a layer of polydimethylsiloxane immersed in heptane.

This paper uses a method based on indentation to characterize a polydimethylsiloxane (PDMS) elastomer submerged in an organic solvent (decane, heptane, pentane, or cyclohexane).  An indenter is pressed into a disk of a swollen elastomer to a fixed depth, and the force on the indenter is recorded as a function of time.  By examining how the relaxation time scales with the radius of contact, one can differentiate the poroelastic behavior from the viscoelastic behavior.  By matching the relaxation curve measured experimentally to that derived from the theory of poroelasticity, one can identify

When an indenter is pressed into a gel to a fixed depth, the solvent in the gel migrates, and the force on the indenter relaxes. Within the theory of poroelasticity, the force relaxation curves for indenters of several types are obtained in a simple form, enabling indentation to be used with ease as a method for determining the elastic constants and permeability of the gel. The method is demonstrated with a conical indenter on an alginate hydrogel.

The University of California, Santa Barbara (UCSB), is commencing a basic research program to establish Virtual Tests for high temperature ceramic composite materials. This activity will be supported within the new National Hypersonic Science Center, Structures and Materials, which is funded by NASA and the U.S. Air Force Office of Scientific Research.The overall program involves a number of institutions, led by Teledyne Scientific Co., in Thousand Oaks, California (Drs. David Marshall and Brian Cox).

In a lithium-ion battery, both electrodes are atomic frameworks that host mobile lithium ions. When the battery is being charged or discharged, lithium ions diffuse from one electrode to the other. Such an insertion reaction deforms the electrodes, and may cause the electrodes to crack. This paper uses fracture mechanics to determine the critical conditions to avert cracking. The method is applied to cracks induced by the mismatch between phases in crystalline particles of LiFePO4

SERC launched the A*STAR Investigatorships in 2007.
This prestigious award for top international young research talent,
tenable at our research institutes, aims to nurture young talent and
build R&D capabilities in Singapore. This year, the award is open
for applications in the following areas:

- Cognitive Systems, including Robotics
- Metamaterials and Plasmonics
- Bioenergy and Energy Storage Technologies
- Medical Technologies for Diagnostics