News & EventsDepartment Events
Events
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Oct22
EVENT DETAILS
lessThe maximum stress and displacement in a cylindrical bar subjected to impact by a dropped weight are determined for linearly elastic, elastoplastic (metallic), and hyperelastic (rubber-like) materials. Both tensile and compressive impacts are considered for different impact velocities. The analysis is based on an extension of the classical energy approach of infinitesimal linear elasticity. It is assumed that the work done on the bar by the falling weight is equal to its initial kinetic energy plus the change in its gravitational potential energy, evaluated with respect to the deformed configuration of the bar when the velocity of the dropped weight becomes zero. The mass of the impacted bar is assumed to be much smaller than that of the falling weight, so that the inertia of the bar and wave-propagation effects can be neglected.
After reviewing the classical analysis for linear elasticity, the approach is extended to a bilinear elastoplastic material model and subsequently to the nonlinear Ramberg–Osgood, Ludwik, and Rasmussen material models. For tensile impact, the threshold velocity for the onset of necking is determined as a function of the mass, material, and geometric properties of the bar, assuming that the impact velocity is sufficiently low that strain-rate effects can be neglected. For compressive impact of slender bars, the buckling stress and corresponding critical impact velocity are determined using Engesser's tangent-modulus theory and von Kármán's reduced-modulus theory.
The analysis is then extended to incompressible rubber-like materials described by the Mooney–Rivlin, neo-Hookean, Gent, Yeoh, Ogden, and Arruda–Boyce hyperelasticity models, as well as to compressible foam-like materials described by the Blatz–Ko, Hill–Storäkers, and compressible neo-Hookean models. Other coupled and uncoupled compressible hyperelastic models are also considered and discussed. For a linearly elastic bar, the maximum stress at zero impact velocity is twice the corresponding static stress. For nonlinear bars the dynamic factor can differ substantially from 2, depending on the magnitude of the dropped weight and the degree and type of material nonlinearity.
The seminar will address both the research and teaching aspects of this mechanics problem, including energy considerations, wave propagation, material nonlinearity, instability, and constitutive modeling.TIME Thursday, October 22, 2026 at 11:00 AM - 11:00 PM
LOCATION B211, Technological Institute map it
CONTACT Ezri Alfie ezri.alfie@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Oct23
EVENT DETAILS
lessApplication for degree due to The Graduate School to receive a degree in Fall
TIME Friday, October 23, 2026
CONTACT Office of the Registrar nu-registrar@northwestern.edu EMAIL
CALENDAR University Academic Calendar
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Oct23
EVENT DETAILS
lessEpigenetics, Biological Aging, and Epidemiology
TIME Friday, October 23, 2026 at 2:00 PM - 3:00 PM
LOCATION A230, Technological Institute map it
CONTACT Logan Hart logan.hart@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Nov4
EVENT DETAILS
lessOn the Role of Large Language Models and Agents from the Scientific Record to Certified Mechanics and Our Classrooms
TIME Wednesday, November 4, 2026 at 11:00 AM - 12:00 PM
LOCATION A230, Technological Institute map it
CONTACT Logan Hart logan.hart@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Nov6
EVENT DETAILS
lessHow the exposome in infancy influences trajectories of chronic inflammation, aging, and disease
TIME Friday, November 6, 2026 at 2:00 PM - 3:00 PM
LOCATION A230, Technological Institute map it
CONTACT Logan Hart logan.hart@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Nov11
EVENT DETAILS
lessCould we use instabilities instead of avoiding them? Mechanical instabilities are usually seen as failure modes. However, recent work shows they can instead be harnessed to give structures rapid, switchable, and adaptive behaviors. Snapping instabilities, for example, allow sudden transitions between stable shapes. In this talk, I introduce countersnapping, a new type of snapping instability in which a structure becomes stronger and stiffer as it snaps, giving rise to programmable stiffness, tunable natural frequency, and hinting toward the possibility of domino-like wave propagation. I will discuss some avenues on how mechanical instabilities could be used to reach structural adaptability using propagation waves.
TIME Wednesday, November 11, 2026 at 11:00 AM - 12:00 PM
LOCATION A230, Technological Institute map it
CONTACT Logan Hart logan.hart@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Nov13
EVENT DETAILS
lessManagement of powerline corridors affects biodiversity and provision of ecosystem services in the Chicago metropolitan region
TIME Friday, November 13, 2026 at 2:00 PM - 3:00 PM
LOCATION A230, Technological Institute map it
CONTACT Logan Hart logan.hart@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Nov16
EVENT DETAILS
lessRegular registration for Winter quarter begins
TIME Monday, November 16, 2026
CONTACT Office of the Registrar nu-registrar@northwestern.edu EMAIL
CALENDAR University Academic Calendar
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Nov18
EVENT DETAILS
lessPermeability is a key property governing fluid transport in geomaterials and plays an important role in subsurface energy technologies such as deep geothermal stimulation, geological CO₂ sequestration, and hydrogen storage. In low-permeability rocks, however, conventional permeability measurements such as the classical transient pulse-decay test can take days, making rapid and reliable characterization challenging. This research seeks to infer permeability from the early-time portion of transient pressure measurements using the Integral-Balance Method. The early-time pressure distribution within the rock specimen is first represented by an assumed profile function, and global mass conservation will be then enforced by integrating the governing equations over the evolving difusion front. This technique reduces the original system of partial differential equations describing the test to a system of ordinary differential equations, leading to a robust regression procedure for determining rock permeability from early-time pressure data. A laboratory test using Vermont serpentinite successfully validated the method. Further extension of the framework to field-scale diagnostic tests, such as pressure fall-off test, will also be discussed.
TIME Wednesday, November 18, 2026 at 11:00 AM - 12:00 PM
LOCATION A230, Technological Institute map it
CONTACT Ezri Alfie ezri.alfie@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Nov19
EVENT DETAILS
lessHow precisely can we measure and control the motion of an object? Quantum mechanics gives a famously unsettling answer: the act of measurement inevitably disturbs the motion we seek to measure — this is the famous uncertainty principle of Heisenberg, theorized almost exactly 100 years ago. I will describe recent experiments that approach these limits using tangibly macroscopic mechanical oscillators, including the measurement and quantum control of motion of a kilogram-scale mirror, and of a centimeter-scale torsional oscillator. At these scales, quantum mechanics becomes a theory we can test with objects we can see and weigh—opening the possibility of asking whether quantum mechanics survives unchanged in the macroscopic world, and ultimately whether gravity itself must obey quantum rules, one of the pre-eminent problems of modern physics.
TIME Thursday, November 19, 2026 at 10:00 AM - 12:00 PM
LOCATION A230, Technological Institute map it
CONTACT Ezri Alfie ezri.alfie@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Nov20
EVENT DETAILS
lessDissertation, PhD Final Exam, and change of grade forms due to TGS for Fall PhD candidates
TIME Friday, November 20, 2026
CONTACT Office of the Registrar nu-registrar@northwestern.edu EMAIL
CALENDAR University Academic Calendar
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Nov20
EVENT DETAILS
lessInvestigating Stream Connectivity and Water Quality Across Space and Time
TIME Friday, November 20, 2026 at 2:00 PM - 3:00 PM
LOCATION A230, Technological Institute map it
CONTACT Logan Hart logan.hart@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Nov25
EVENT DETAILS
lessThanksgiving Vacation begins at 6:00 PM (No classes, University offices closed)
TIME Wednesday, November 25, 2026
CONTACT Office of the Registrar nu-registrar@northwestern.edu EMAIL
CALENDAR University Academic Calendar
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Nov30
EVENT DETAILS
lessFall Classes Resume
TIME Monday, November 30, 2026
CONTACT Office of the Registrar nu-registrar@northwestern.edu EMAIL
CALENDAR University Academic Calendar
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Dec4
EVENT DETAILS
lessSensing Lead (Pb) with DNA
TIME Friday, December 4, 2026 at 2:00 PM - 3:00 PM
LOCATION A230, Technological Institute map it
CONTACT Logan Hart logan.hart@northwestern.edu EMAIL
CALENDAR McCormick - Civil and Environmental Engineering (CEE)
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Dec5
EVENT DETAILS
lessFall classes end
TIME Saturday, December 5, 2026
CONTACT Office of the Registrar nu-registrar@northwestern.edu EMAIL
CALENDAR University Academic Calendar
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Dec7
EVENT DETAILS
lessFall Exams begin
TIME Monday, December 7, 2026
CONTACT Office of the Registrar nu-registrar@northwestern.edu EMAIL
CALENDAR University Academic Calendar
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Dec12
EVENT DETAILS
lessFall exams end
TIME Saturday, December 12, 2026
CONTACT Office of the Registrar nu-registrar@northwestern.edu EMAIL
CALENDAR University Academic Calendar
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Dec12
EVENT DETAILSmore info
lessThe ceremony will take place on Saturday, December 12 in Pick-Staiger Concert Hall, 50 Arts Circle Drive.
TIME Saturday, December 12, 2026 at 4:00 PM - 6:00 PM
LOCATION Pick-Staiger Concert Hall map it
CONTACT Andi Joppie andi.joppie@northwestern.edu EMAIL
CALENDAR McCormick School of Engineering and Applied Science