research

We investigate turbulence-induced vibrations in a confined annular flow configuration representative of pressurized water reactor internals. The experimental setup consists of a rigid inner cylinder mounted on two flexible rectangular plates inside a cylindrical vessel. Building on our previous work, analytical expressions for the fluid-elastic forces in quiescent fluid are derived, accounting for added mass, damping, partial immersion, viscous, and confinement effects.

The Executive Committee (EC) of the Applied Mechanics Division (AMD) of ASME is pleased to announce the call for nominations for the Applied Mechanics Division Awards.

Nominations will be due by September 15, 2026.

The AMD seeks nominations for the awards listed below.

Timoshenko Medal: 

With funding from the Haythornthwaite Foundation, the Executive Committee (EC) of the Applied Mechanics Division (AMD) of ASME is pleased to announce the Haythornthwaite Research Initiation Grant Program, targeting university faculty engaged in research in theoretical and applied mechanics that are at the beginning of their academic careers. Applicants must hold a tenure-track appointment at the rank of Assistant Professor at a US university on October 1, 2026, and must not be more than 5 years beyond receipt of their doctoral degree at the time the award is made. 

Dear colleagues,

I am pleased to invite you to the next webinar in the Extreme Mechanics Letters (EML) Webinar Series.

Our upcoming seminar will be delivered by Prof. Omar Saleh (UCSB):

"Droplets that stiffen gels"

Date: Friday, 14 August 2026

Time: 10:00 am Boston / 3:00 pm London / 4:00 pm Paris / 10:00 pm Beijing

Discussion leader: Prof. Robert M McMeeking (UCSB)

Prof. Yu Deng of the University of Chicago Department of Mathematics won the Fields Medal in Mathematics for solving Hilbert's Sixth Problem. How does this differ from the Unified Mechanics Theory? I raised this question to Gemini 3.1 Pro Extended Thinking. The answer is attached. I hope you enjoy reading it.

Maximiliano Larrain Silva               Amit Acharya

A solution procedure is formulated and solved for treating the nonlinear Dissipation Inequality as a constraint equation within continuum mechanics, and allowing for incomplete knowledge of constitutive behavior. The scheme is demonstrated in the context of the rate-dependent, elastoplastic response of a bar, resulting in a nonlinear problem of constrained optimization. Both closed form and computational results are developed. The computational solutions utilize a sequence of convex optimization problems, and are shown to be accurate. In the example considered, the approach is shown to automatically correct an (intentionally) faulty constitutive specification, resulting in the solution to be in accord with the fundamental postulates of continuum mechanics.

Context:

Arash Yavari         Amit Acharya

Curl forces are position-dependent, non-conservative, and non-dissipative forces that, in general, cannot be derived from an ordinary potential energy. Consequently, their equations of motion do not, in general, follow from a standard variational principle. In this paper, we present a dual variational formulation for particle dynamics under curl forces. By introducing variables dual to position and velocity and an auxiliary function, we construct a pre-dual action in which the equations of motion act as constraints. Stationarity with respect to the primal variables defines a dual-to-primal mapping, whose substitution into the pre-dual action gives an action expressed entirely in terms of the dual variables. The Euler–Lagrange equations of the dual action recover both the original equations of motion and their prescribed initial conditions. We also introduce an auxiliary dual Hamiltonian that is conserved along stationary dual trajectories, although it does not represent the physical energy. The formulation is illustrated using two nonlinear curl force fields in two and three dimensions and the classical Ziegler column. These examples demonstrate that non-conservative curl-force dynamics can admit variational descriptions even in the absence of an ordinary potential energy or a conventional Lagrangian.

Our latest paper is now freely accessible for the next 50 days from this link: https://authors.elsevier.com/a/1nUCG3In-v8hqF