1. Bioinspired Tire Tread Design

The dynamic friction performance of frog toe-pad inspired surface patterns is investigated in three folds. First, frog toe-pad morphology is mimicked, designed, and fabricated using 3D printing technology. Friction coefficients of the models are measured experimentally over a wet medium, with varying velocity, load, and sliding direction. Second, numerical simulation is employed to study the contact area, sliding displacement, and frictional stress of the model tread patterns. Surfaces with different low frictional coefficients are considered to simulate the presence of wet medium and surface roughness. Third, an analytical model is utilized to calculate the water squeeze-out time, as well as the height difference of drained water during wet surface conditions. Among three different bioinspired models, built to compare with a sample tire design, the double-layered studded hexagonal pattern shows the best wet traction performance.

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1. A. Banik, and K.T. Tan (2020). Dynamic Friction Performance of Hierarchical Biomimetic Surface Pattern Inspired by

Frog Toe‐Pad. Advanced Materials Interfaces, 7, 2000987. DOI

2. Low Velocity Ice Impact on CFRP Sandwich Panel

A customized mold and foam standing were built to prepare ice impactors according to the compatibility of the impact testing machine. The differences in ice-fracture mechanism from the low-velocity impact on steel and CFRP sandwich panel were evaluated. A 60% increase in entire ice damage was discovered from the collision with CFRP than steel.

Moreover, cylindrical-shaped ice impactors of similar length, as well as similar volume of conical ice impactors, were prepared. The fracture mechanism and impact performance of each impactor were discussed.

Read Related Article:

1. A. Banik and K.T. Tan. (2020). Low-Velocity Ice Impact Testing on Steel and CFRP Specimen, Conference Proceeding for American Society for Composites 35^th Technical Conference (Virtual), 14-17 Sept, Jersey City, New Jersey, USA. DOI

3.Low Velocity Equal Energy Impact on CFRP in Arctic Condition

In this study, the impact response and damage mechanisms of carbon fiber reinforced polymer (CFRP) under equal impact energy but different mass-velocity combinations are investigated. CFRP samples are also subjected to impact at room temperature (23ºC) and low temperature (-70ºC) conditions with the aim to understand composite behavior in a cold Arctic environment. Furthermore, this study explores the effect of ice formed on the substrate surface, so as to elucidate the influence of surface ice on impact damage. Different damage modes are detected by X-ray micro-computed tomography for different mass-velocity configurations and temperatures. This study reveals that the presence of surface ice contributed to altering the stress distribution on the CFRP specimen. This research provides an understanding on the dynamic behavior of CFRPs when deployed in low-temperature icy conditions.

Read Related Article:

1. A. Banik and K.T. Tan. (2021). Effect of impactor mass on CFRP in Arctic condition under low-velocity impact, Conference Proceeding for American Society for Composites 36^th Technical Conference (Virtual), 20-22 Sept, Texas, USA. DOI

For any questions on this research, please reach at ab353@uakron.edu.

4.Damage Analysis of Portable Concrete Barriers

5. Impact Performance and Bending Behavior Analysis of Fiber Reinforced Composite Sandwich Structures in Arctic Condition

This study investigates the low-velocity impact performance and bending behavior with underlying damage mechanisms of woven carbon fiber reinforced polymer (CFRP), glass fiber reinforced polymer (GFRP), and carbon-glass fiber hybrid face sheets sandwich panel. A series of low-velocity impact tests (3.46 m/s and 4.92 m/s) is performed at 15 J and 30 J energy using a drop tower testing machine. These energy levels are selected so that lower energy of 15 J can mostly damage the front face sheet, and 30 J impact penetrates the front face sheet and crushes the PVC core to some extent. Specimens are subjected to impact at room temperature (23 °C) and low temperature (-70 °C) to mimic the arctic environment. A relative comparison of the impact response from different sandwich specimens under different conditions is presented in terms of force, displacement, and energy.

Though force-time curves show a smooth loading phase for CFRP and GFRP specimens at 15J, fiber breakage with severe load drop is observed on the front face sheet of hybrid sandwich composites at both temperatures.

Moreover, post-impact bending tests are conducted to investigate the residual flexural strength of sandwich structures from ASTM C393 standard with a crosshead speed of 0.5 mm/min. No significant differences in peak load values are observed for different types of non-impacted sandwich composites. But post-impacted GFRP sandwich specimens outperform other sandwich composites by producing greater peak forces with higher displacement and as such, provide better flexural strength at both temperatures. CFRP specimens show the least flexural resistance under these conditions. Debonding dominates at the back face sheet of all composites at 15 J due to greater deflection, whereas fiber breakage on the front face sheet with core densification and core shear are major damage modes at 30J post-impacted specimens. GFRP and hybrid sandwich present better damage tolerance and flexural strength in low temperatures due to the improvement in the bonding between glass fiber and matrix. (Research on progress)

6. Investigation of the Impact Tolerance of Sea Urchin Shell Structures

7. Design of a Super Tough Bioinspired Double Core Sandwich Composite Structure

Nature is rich with many resources that have unique characteristics depending on the environmental condition. Advancement in technology has enabled researchers to study and explore various biological models and thus use their internal design in engineering applications. Furthermore, progress in 3D printing is now allowing preparing complicated biological design comfortably and thus evaluate their mechanical properties. In this study, a design of double core sandwich composite is proposed after being inspired by five types of biological models. It is expected that the combination of different toughening mechanisms from different natural sources will make the sandwich structure super tough. As such, it will show superior damage tolerance and impact performance than the conventional design. 3D printing of the composite will also remove the complexities in the traditional composite manufacturing process. (Research on progress)