Crosswind stability of vehicles under nonstationary wind excitation


Book Description

This work has studied the crosswind stability of vehicles under nonstationary wind excitation in various scenarios. Railway vehicles running on curved and straight track with varying vehicle speed are studied. Road vehicles are classified into different categories. For each vehicle class, a corresponding worst-case vehicle model has been built. As the wind excitation on the vehicle is a stochastic process, a risk analysis has to be carried out and failure probabilities are computed and analyzed.







On direct and inverse problems related to longitudinal impact of non-uniform elastic rods


Book Description

The impact of two non-uniform elastic rods is considered and a recursive method was developed that solves the inverse problem: Find the location-dependent impedance function of the impacting rod that generates a prescribed impact force. The developed method delivers exact solutions in closed-form. Moreover, a condition is derived which states if a physically meaningful solution exists. Finally, the underlying 1D model has been validated experimentally.




Lubricant transport towards tribocontact in capillary surface structures


Book Description

To counter lubricant shortage at a frictional contact (starvation), lubrication liquids, e.g. oils, are actively transported from a distant location towards the undersupplied tribocontact. This is done via small channels or generally via structures cut into a flat surface. In this way one can use capillary force as a cheap and reliable driver of the lubricant flow. Numerical modeling and experiments show that this method can be considered a promising new option to enhance tribocontact operation.




An efficient solution procedure for elastohydrodynamic contact problems considering structural dynamics


Book Description

This work presents an efficient solution procedure for the elastohydrodynamic (EHD) contact problem considering structural dynamics. The contact bodies are modeled using reduced finite element models. Singly diagonal implicit Runge-Kutta (SDIRK) methods are used for adaptive time integration. The structural model is coupled with the nonlinear Reynolds Equation using a monolithic coupling approach. Finally, a reduced order model of the complete nonlinear coupled problem is constructed.




Nonparametric identification of nonlinear dynamic systems


Book Description

A nonparametric identification method for highly nonlinear systems is presented that is able to reconstruct the underlying nonlinearities without a priori knowledge of the describing nonlinear functions. The approach is based on nonlinear Kalman Filter algorithms using the well-known state augmentation technique that turns the filter into a dual state and parameter estimator, of which an extension towards nonparametric identification is proposed in the present work.




Dynamics of Rotors on Refrigerant-Lubricated Gas Foil Bearings


Book Description

The gas foil bearing (GFB) technology is a key factor for the transition to oil-free rotating machinery. Among numerous advantages, GFBs offer the unique ability to be lubricated with working fluids such as refrigerants. However, the computational analysis of refrigerant-lubricated GFB–rotor systems represents an interdisciplinary problem of enormous complexity. This work pushes forward existing limits of feasibility and establishes a new strategy that enables stability and bifurcation analyses.




On the Influence of Piecewise Defined Contact Geometries on Friction Dampers


Book Description

This work considers dampers that do not solely focus on a single strategy but instead combine them. The capabilities of conventional dry friction dampers are expanded by taking into account piecewise defined contact geometries. This leads to friction dampers that change their behavior depending on the amplitude of the oscillations. The vibration damping device in this work, introduces damping at high oscillation amplitudes and takes advantage of absorption at low oscillation amplitudes.







Microbial Mitigation of Stress Response of Food Legumes


Book Description

Microbial Mitigation of Stress Responses of Food Legumes provides knowledge on the impact of abiotic and biotic stress on the agriculture of grain legumes especially pulses and it critically reviews the cutting-edge research in exploring plant microbe interactions to mitigate the stress. It helps in understanding the fundamentals of microbial-mediated management of abiotic and biotic stress in grain legumes. Salient features:  Describes the usefulness of microbiome of plant/insects for enhancing the production of grain legumes  Focuses on recent advances in microbial methods for mitigating the stress and their application in sustainability of legume production  Provides a unique collection of microbial data for the improvement of legume productivity  Details microbial metabolites at the gene and molecule levels for plant stress management The reader will get all essential and updated information on various stress factors, crop responses, and microbial-mediated stress management for better food legume production.




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