Feb 26

Design, Analysis, and Fabrication of Pericyclic Mechanical Transmission with Straight Bevel Gears

218 Hammond
9 a.m.

Additional Information:

Traditionally, the usage of the transmission concepts that offer high reduction ratio in a compact space has been limited to very low torque applications. The Pericyclic drive is a breakthrough power-transmission concept that has the potential to address many of the problems posed by large gearboxes - noise, maintenance cost, and low power density. The key innovations of the Pericyclic drive are its nutational motion kinematics which enables dramatically enhanced gear ratios from a single stage (approx. 50:1) with a compact architecture, load sharing over many teeth (upto 10% of tooth complement), and power density capabilities well beyond the current state-of-the-art. Kinematically, a Pericyclic drive is similar to epicyclic bevel gear trains with axes intersecting at large angles. Potential applications include rotorcraft, wind turbines, and urban air mobility (UAM) vehicles.


This research attains three of the goals in the development of Pericyclic transmission technology: (i) mature the component level design analysis tools, (ii) integrate these individual design modules in a system level framework to design the transmission for given operating parameters, and (iii) use this framework to design a prototype for actual fabrication and testing under load. Geared transmissions being complex systems; the research spans several disparate fields such as contact mechanics, finite element methods, lubrication analysis, multibody dynamic analysis, and system design for X (X = efficiency, weight, life, manufacturing). The system level design procedure integrates a novel loaded tooth contact analysis (LTCA), elastohydrodynamic lubrication (EHL) analysis, bearing analysis, and shaft design, within a framework in which design decisions are guided by constraints posed by several factors such as assembly, ease of manufacturing, operational space, component life requirements, optimal component geometry and positioning etc. The designs for different input power levels obtained from the framework demonstrate the high power density capability, and efficiency comparable to conventional multi-stage planetary drivetrains. Finally, a small scale 50 HP prototype design with a reduction ratio of 32:1 has been refined for fabrication and subsequent testing at NASA Glenn transmission test facility. The performance evaluation charts for the test article have been obtained from the overall system analysis model for validation against future test results.


Feb 26

Mechanics of cell-nanomaterial interactions: applications in nanomedicine and nanotoxicity

220 Hammond Building
3:35 p.m.

Additional Information:


There is an urgent societal need to understand the biological interactions of nanomaterials which are being produced and released into the environment by nearly a million tons per year, as well as to explore applications of nanomedicine to treat diseases. This talk aims to discuss some of the recent experimental, modelling and simulation studies on cell uptake pathways of nanaomaterials with different geometrical (e.g., size, shape, orientation), mechanical (e.g., stiffness) and chemical (e.g., surface functionalization) properties of nanomaterials; cellular and Intracellular packaging of nanomaterials and cytotoxicity; and toxicity and damage mechanisms of nanomaterials to cells and membranes.

Short Bio

Huajian Gao received his Ph.D. in Engineering Science from Harvard University. Previously a Professor at Stanford University and Director at the Max Planck Institute for Metals Research, he is currently the Walter H. Annenberg Professor of Engineering at Brown University. His research has been aimed at understanding basic principles that control mechanical properties and behaviors of materials in both engineering and biological systems. He is the Editor-in-Chief of Journal of the Mechanics and Physics of Solids, the leading journal of his field, and a Member of both National Academy of Engineering and National Academy of Sciences.




Feb 26

Microcredentialing Workshop: Business Principles for Engineers

125 Reber
4:30 - 8:30 p.m.

Register in 139 Reber with $25 refundable deposit

Additional Information:

Technology has enabled radically new business models supported by shared global platforms. The workforce is more dynamic as long-tenure positions at companies are less common, and intellectual capital management has become vital to maintaining a competitive market advantage. Students seeking their first jobs benefit from prior workplace experience and knowledge of professional skills, including business communication, finance, and project management. New models of online learning provide access to just-in-time learning and the opportunity to connect basic research innovation with market opportunity. The lean start-up model and interest in entrepreneurship has opened new opportunities for small business creation.

This session will provide an introduction to current changes underway in the market and basic business and financial concepts important for operating in today’s workplace.


Feb 28

A Fundamental Investigation of the Effect of Freestream Turbulence Parameters on the Time-mean and Dynamic Behavior of Junction Flow

214 Reber
11 a.m.

Additional Information:

Junction flow is a phenomenon that is common to both natural and industrial processes, occurring where an incoming flow above a wall meets an obstacle protruding from the wall, such as occurs at wing-body junctions on aircraft or turbine blade/vane endwalls in a gas turbine.  At the junction of the obstacle and the wall, the incoming boundary layer separates and forms a region of backflow along the endwall in front of the obstacle.  This backflow sustains the presence of a horseshoe vortex system (HS Vortex) – a coherent vortex feature centered near the endwall in front of the obstacle leading edge, with legs that wrap around the obstacle following the mainstream flow.  In turbulent flows, the horseshoe vortex system is known to be complex in structure and highly unsteady in regards to the position of its primary vortex core.  Due in part to its unsteadiness, the presence of the horseshoe vortex system within the junction significantly increases endwall heat transfer in front of the obstacle. It can also produce significant dynamic pressure loading on obstacle surfaces near the junction.


Understanding and potentially controlling the dynamic behavior of the HS vortex in an applied setting is currently difficult due to the need for a fundamental understanding of how freestream parameters, such as Reynolds number and freestream turbulence levels, effect flow in the junction. To address this need, time-resolved flowfield measurements of the junction region were used to quantify the unsteadiness of the junction region under a wide range of freestream turbulence and Reynolds number conditions relevant to industrial applications.  Analysis of these measurements show that freestream Reynolds number significantly influences the structure of the horseshoe vortex system and other vorticity features in the lower boundary layer.  This leads to a modest increase in time-mean turbulent kinetic energy in the vortex region.  The presence of moderate to high freestream turbulence intensity significantly increases unsteadiness in the junction under low turbulent Reynolds number conditions, but is less effective as Reynolds number increases.  This effect is caused by the transport of turbulence features from the freestream and upper boundary layer into the junction through entrainment in the leading edge downflow.  At low Reynolds number, these features interact with the horseshoe vortex system, energizing its unsteady motions and the unsteadiness of backflow in the region.  Large integral length scales can also played a role in augmenting this effect at high turbulence intensities by increasing the rate of impingement of large turbulence features along the wing leading edge at length scale magnitudes above a certain threshold. Altogether, this understanding directly supports efforts to model or control the heat transfer and pressure loading effects of unsteadiness in the junction under a wide range of freestream Reynolds number and turbulence intensity conditions. 


Mar 22

Microcredentialing Workshop: Extraordinary Results, Session 3

E-Knowledge Commons
3:30 p.m. - 5:30 p.m.

Additional Information:

Register in 139 Reber.




With more than 60 faculty members, 330 graduate students, and 800 undergraduate students, the Penn State Department of Mechanical Engineering embraces a culture that welcomes individuals with a diversity of backgrounds and expertise. Our faculty and students are innovating today what will impact tomorrow’s solutions to meeting our energy needs, homeland security, biomedical devices, and transportation systems. We offer B.S. degrees in mechanical engineering as well as resident (M.S., Ph.D.) and online (M.S.) graduate degrees in mechanical engineering. See how we’re inspiring change and impacting tomorrow at

Department of Mechanical Engineering

137 Reber Building

The Pennsylvania State University

University Park, PA 16802-4400

Phone: 814-865-2519