Industrial Process Diagnosis based on Information and Time Domain Models

2021 ◽  
Author(s):  
Dorel Aiordachioaie
Keyword(s):  
Time Domain ◽  
Industrial Process ◽  
Process Diagnosis ◽  
Domain Models

A Comprehensive Model for Cutting Dynamics

2005 ◽  
Author(s):  
Achala V. Dassanayake ◽  
C. Steve Suh
Keyword(s):  
Time Domain ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Nonlinear Behavior ◽  
Work Piece ◽  
Special Focus ◽  
Comprehensive Model ◽  
Time Frequency ◽  
Domain Models ◽  
Tool Deflections

A three dimensional dynamic model describing turning operation involving whirling caused by mass imbalance is presented. Both the workpiece and tool deflections affected by nonlinear regenerative forces with instantaneous cutting speed and feed are included. The work piece is modeled as a system of three rotors; namely, unmachined, being machined and machined, connected by a flexible shaft. Special focus is given to the middle rotor where cutting forces act and the new surface is being generated. The nonlinear behavior of the system is studied using instantaneous frequency. The stable and unstable situations are illustrated in time domain as well as time-frequency domain. Models with and without whirling are considered and two sets of results are compared with the experimental results published in the literature.

scholarly journals Truck suspension incorporating inerters to minimise road damage

2020 ◽  
Vol 234 (10-11) ◽  
pp. 2693-2705
Author(s):  
Xiaofu Liu ◽  
Jason Z Jiang ◽  
Andrew Harrison ◽  
Xiaoxiang Na
Keyword(s):  
Time Domain ◽  
Damage Index ◽  
Low Complexity ◽  
Nonlinear Relationship ◽  
Heavy Vehicles ◽  
The Road ◽  
Suspension Systems ◽  
Damage Reduction ◽  
Leaf Springs ◽  
Domain Models

Road damage caused by heavy vehicles is a serious problem experienced worldwide. This paper investigates the potential for reduction in road damage by incorporating the inerter element into truck suspension systems. Initially, quarter-car, pitch-plane and roll-plane models with two low-complexity inerter-based linear suspension layouts are investigated in the frequency domain. Reductions of the J95 road damage index for each model are identified against conventional parallel spring–damper truck suspension layouts. It is also shown that the proposed suspensions are capable of enhancing the roll stability while keeping the road damage at a given level. Subsequently, the nonlinear relationship between force and displacement as manifested by leaf springs is incorporated into the pitch-plane and roll-plane time-domain models. These confirm the potential advantage of inerter-based suspension layouts for road damage reduction.

Two time domain models for fatigue life prediction under multiaxial random vibrations

2019 ◽  
Vol 233 (13) ◽  
pp. 4707-4718 ◽  
Author(s):  
Zhengbo Luo ◽  
Huaihai Chen ◽  
Xudong He ◽  
Ronghui Zheng
Keyword(s):  
Fatigue Life ◽  
Time Domain ◽  
Life Prediction ◽  
Random Vibration ◽  
Notch Root ◽  
Critical Plane ◽  
Crack Orientation ◽  
Spectral Density Matrix ◽  
Power Spectral ◽  
Domain Models

Two time domain models for fatigue life prediction under multiaxial random vibrations are developed on the basis of the critical plane approach. Firstly, the stress power spectral density matrix of each node at the notch root of the test specimen is obtained by the random vibration analysis with finite element method, and the stress time-histories are generated from the stress power spectral density matrix by the time domain randomization approach. Then, the fatigue life of each node is predicted based on the damage on the critical plane, where the cumulative damage value is the greatest. The minimum fatigue life of all nodes at the notch root is considered as the fatigue life of the test specimen. Finally, the proposed models are validated by the multiaxial random vibration fatigue test with the 6061-T4 aluminum alloy. The results show that the predicted fatigue lives and predicted crack orientation angles are in good agreement with the experimental fatigue lives and experimentally observed crack orientation angles, respectively.

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