Farewell to Our Guests Peter Risby Andersen (Phd Student, DTU, Kopenhagen) and Shubham Garg (Master Student, IIT, Dehli) – Their Topics


Peter Risby Andersen - Phd-Topic: Numerical & Experimental Study of the Acoustical-Mechanical Interaction at the Micro Scale inclusing Losses

DAGA 2017 in Kiel – Numerical Acoustic Models Including Viscous and Thermal Losses: Review of Existing and New Methods

At the German annual conference for acoustics the chair of vibroacoustics of vehicles and machines presented several topics. One of which was “Numerical Acoustic Models Including Viscous and Thermal Losses: Review of Existing and New Methods”:

The paper reviews numerical methods modeling viscothermal losses. By means of a simple academic test case it compares and investigates the well established acoustic implementations and a newly proposed method that is a combination of the Finite Element Method and the Boundary Element Method.

Figure: Simple Academic Test Case with Coarse Discretization



Shubham Garg - Master Thesis: Uncertainty Quantification in Natural Frequencies of Pretensioned Concrete Beam Strengthened with CFRP Laminate

Supervisors: Dr. -Ing. K. Sepahvand, Dr. Vasant A. Matsagar, Prof. Dr. -Ing. S. Marburg

Due to inherent structure variations, composites show vast complexity in mechanical properties. Free vibration response of prestressed concrete beam with carbon-fiber-reinforced plastic (CFRP) laminate is modeled in a finite element software. The concrete damaged plasticity constitutive model is used to simulate the stress-strain response of concrete and steel prestressing tendon is modeled using the von-Mises plasticity model. This yields a deterministic black-box FEM model for the stochastic simulation. The impact of composite elastic parameter uncertainty on the natural frequency of the strengthened beam is investigated. The uncertain material parameters are represented using truncated generalized polynomial (gPC) expansions with predefined orthogonal basis. A non-intrusive collocation based technique is used to compute the deterministic polynomial chaos coefficients of the natural frequencies. The gPC expansion based simulation technique is observed to be an efficient alternative to computationally demanding Monte Carlo simulation for quantifying uncertainties. Effect of uncertainty level on the response is also studied.Vibrationsantwort des verstärkten Betonbalkens auf.