Multiscale Simulation of the Failure Response of Adhesive-Bonded Structural Joints
By: Bowen Liang
11:30 – Noon E525
Abstract: Adhesive bonding enables the joining of thin and dissimilar materials, which is one of the main requirements for manufacturing lightweight structures in the automotive and aerospace industries. However, due to the small thickness and complex microstructure of the adhesive layer, which is often reinforced with embedded heterogeneities to improve its mechanical behavior, simulating the damage evolution in this layer can be challenging. This work implements a computational cohesive model to investigate the effects of microstructural features such as particles volume fraction, pre-existing flaws, and surface roughness of adherends on the failure response of a heterogeneous adhesive with embedded glass particles. The hierarchical interface-enriched finite element method (HIFEM) is implemented as the main computational engine for simulating the initiation and propagation of damage in the adhesive layer. A new virtual prototyping algorithm is also introduced and integrated with the HIFEM to enable the automated construction of realistic models of the adhesive microstructure based on digital data.
Biography: Bowen Liang received his BSE in Mechanical Engineering from Shanghai Jiaotong University. He is currently working towards his Ph.D. in Mechanical Engineering under Dr. Soheil Soghrati in the Automated Computational Mechanics Laboratory; his work focuses on the automated modeling and analysis of microstructural effects on the heterogeneous adhesives.
Probing the effects of interstitial flow and genetic changes on stroma activation in vitro
By: Alex Avendano
12:10 – 12:40pm E525
Abstract: Tumor stroma that surrounds cancer cells and composed of noncancerous cancer cell-types has emerged as a crucial mediator of tumor progression. Essential to the tumor-promoting properties of the stroma is the activation of its cellular constituents through genetic reprogramming. In addition to genetic alterations, tumors are characterized by elevated levels of interstitial flow (IFF). Mechanical stimulation by IFF is a known activator of stromal fibroblasts, which causes these fibroblasts to adapt a contractile phenotype characterized by expression of α-smooth muscle actin (α-SMA) and remodeling and alignment of ECM collagen fibers. Our expertise in the areas of microscale engineering and microfluidics has been employed to design a microphysiological system that allows compartmentalization of fibroblast seeded collagen hydrogels as well as controlled application of varying levels of IFF. Compartmentalization is achieved by utilizing surface tension and capillary effects to trap the cell seeded collagen hydrogel in the middle channel. Application of controlled IFF is achieved by creating a pressure gradient between the lateral flow channels using a syringe pump with adjustable flow rates. The design was fabricated using SU-8 photolithography and soft lithography techniques for Polydimethylsiloxane (PDMS). Reflectance microscopy has also been used along with the CT-FIRE algorithm to visualize and quantify the alignment of individual collagen fibers within fibroblast seeded hydrogels under static conditions.
Biography: Alex Avendano is a second year Ph.D student working in the Microsystems for Mechanobiology and Medicine Laboratory at Ohio State. His research focuses on the use of microfluidics to study how genetic reprogramming and elevated fluid flow within the tumor microenvironment contribute to the progression of cancer. He obtained his undergraduate degree from Iowa State University and is originally from Carolina, Puerto Rico.