Physical and Numerical Simulations of the Seismic Response of a 1,100 kV Power Transformer Bushing

2018 ◽  
Vol 34 (3) ◽  
pp. 1515-1541 ◽  
Author(s):  
Guo-Liang Ma ◽  
Qiang Xie ◽  
Andrew S. Whittaker
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Simulations ◽  
Seismic Vulnerability ◽  
Power Transformer ◽  
Element Model ◽  
Ground Shaking ◽  
Earthquake Simulator ◽  
Physical Experiments ◽  
Seismic Tests

Power transformers and bushings are key pieces of substation equipment and are vulnerable to the effects of earthquake shaking. The seismic performance of a 1,100 kV bushing, used in an ultra-high voltage (UHV) power transformer, is studied using a combination of physical and numerical experiments. The physical experiments utilized an earthquake simulator and included system identification and seismic tests. Modal frequencies and shapes are derived from white noise tests. Acceleration, strain, and displacement responses are obtained from the uniaxial horizontal seismic tests. A finite element model of the 1,100 kV bushing is developed and analyzed, and predicted and measured results are compared. There is reasonably good agreement between predicted and measured responses, enabling the finite element model to be used with confidence for seismic vulnerability studies of transformer-bushing systems. A coupling of the experimental and numerical simulations enabled the vertically installed UHV bushing to be seismically qualified for three-component ground shaking with a horizontal zero-period acceleration of 0.53 g.

scholarly journals Seismic Vulnerability Evaluation of a Three-Span Continuous Beam Railway Bridge

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Chongwen Jiang ◽  
Biao Wei ◽  
Dianbin Wang ◽  
Lizhong Jiang ◽  
Xuhui He
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Isolation ◽  
Seismic Vulnerability ◽  
Element Model ◽  
Seismic Demand ◽  
Continuous Beam ◽  
Railway Bridge ◽  
Demand Model ◽  
Probabilistic Seismic Demand

In order to evaluate the seismic vulnerability of a railway bridge, a nonlinear finite element model of typical three-span continuous beam bridge on the Sichuan-Tibet railway in China was built. It further aimed at performing a probabilistic seismic demand analysis based on the seismic performance of the above-mentioned bridge. Firstly, the uncertainties of bridge parameters were analyzed while a set of finite element model samples were formulated with Latin hypercube sampling method. Secondly, under Wenchuan earthquake ground motions, an incremental dynamic method (IDA) analysis was performed, and the seismic peak responses of bridge components were recorded. Thirdly, the probabilistic seismic demand model for the bridge principal components under the prerequisite of two different kinds of bearing, with and without seismic isolation, was generated. Finally, comparison was drawn to further ascertain the effect of two different kinds of bearings on the fragility components. Based on the reliability theory, results were presented concerning the seismic fragility curves.

The Potential and Application Areas of Forging Aided by Shear Stress

2013 ◽  
Vol 212 ◽  
pp. 91-94
Author(s):  
Marek Tkocz ◽  
Zdzisław Cyganek ◽  
Franciszek Grosman
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Finite Element Model ◽  
Numerical Simulations ◽  
Metal Forming ◽  
Material Flow ◽  
Strain Distribution ◽  
Vertical Motion ◽  
Element Model ◽  
Local Strains

The paper demonstrates the potential of unconventional metal forming method that consists in introducing shear stress at the die/workpiece interface during compression. In practice it can be realized by induction of reciprocating, vertical motion of a punch that adheres strongly to a workpiece. To estimate an effect of the method on the material flow, a relevant finite element model has been developed and the selected results of numerical simulations are presented in the paper. In comparison to the conventional forging, forming aided by shear stress is able to provide a number of benefits such as significant increase of local strains, lower press loads and the opportunity to control the strain distribution in the workpiece volume. Perspectives for continuation of the studies as well as possible application areas of forging aided by shear stress are discussed in the summary.

A Comparison of Ship-Mounted and Cage-Mounted Passive Heave Compensation Systems

2000 ◽  
Vol 122 (3) ◽  
pp. 214-221 ◽  
Author(s):  
Frederick R. Driscoll ◽  
Meyer Nahon ◽  
Rolf G. Lueck
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Simulations ◽  
Deep Sea ◽  
Natural Frequencies ◽  
Element Model ◽  
Sea State ◽  
Marine Systems ◽  
Compensation Systems ◽  
Safe Operating

Tethered marine systems experience large tensile loads in their tether when operating in rough seas. Heave compensation systems can be used to reduce these loads and increase the safe operating sea states. In this work, a discrete representation of a passive heave compensator is developed and added to a finite-element model of a deep-sea ROV system to investigate the performance of ship-mounted and cage-mounted compensation systems. Numerical simulations are performed for operating depths ranging from 3280–16,400 ft (1000–5000 m) and a range of compensator stiffnesses. Both ship and cage-mounted systems reduced the natural frequencies, rms cage motion and rms tension, and extended the operating sea state of the ROV. During extreme seas, the cage-mounted compensator effectively eliminated all snap loads. However, the compensator’s characteristics must be carefully chosen because a poorly designed compensator can exacerbate operational problems. [S0892-7219(00)00903-1]

Patient-Specific Finite Element Model of a Spinal Tumor for Thermal Ablation

2011 ◽  
Vol 138-139 ◽  
pp. 937-940
Author(s):  
Jin Li Ding ◽  
Qun Nan ◽  
You Jun Liu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Simulations ◽  
Thermal Ablation ◽  
Three Dimensional ◽  
Element Model ◽  
Spinal Tumor ◽  
Patient Specific ◽  
Dimensional Reconstruction ◽  
The Finite Element Model

Objective: The purpose of this research is to establish a patient-specific finite element model of a spinal tumor and provide a preparation for the later numerical simulations. Method: Two steps, including three-dimensional reconstruction of the spinal tumor and its associated tissues, grid generations, are carried out for the establishment of the finite element model. Results: A patient-specific finite element model including a spinal tumor and its associated tissues is established. Conclusion: Patient-specific finite element model is a preparation for the surgical planning on thermal ablation, and the later numerical simulations will provide beneficial tutorials for surgeons.

scholarly journals A Computational Model to Describe the Regional Interlamellar Shear of the Annulus Fibrosus

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Kevin M. Labus ◽  
Sang Kuy Han ◽  
Adam H. Hsieh ◽  
Christian M. Puttlitz
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Annulus Fibrosus ◽  
Element Model ◽  
Shear Behavior ◽  
Intervertebral Disk ◽  
Element Analysis ◽  
Physical Experiments ◽  
The Finite Element Model

Interlamellar shear may play an important role in the homeostasis and degeneration of the intervertebral disk. Accurately modeling the shear behavior of the interlamellar compartment would enhance the study of its mechanobiology. In this study, physical experiments were utilized to describe interlamellar shear and define a constitutive model, which was implemented into a finite element analysis. Ovine annulus fibrosus (AF) specimens from three locations within the intervertebral disk (lateral, outer anterior, and inner anterior) were subjected to in vitro mechanical shear testing. The local shear stress–stretch relationship was described for the lamellae and across the interlamellar layer of the AF. A hyperelastic constitutive model was defined for interlamellar and lamellar materials at each location tested. The constitutive models were incorporated into a finite element model of a block of AF, which modeled the interlamellar and lamellar layers using a continuum description. The global shear behavior of the AF was compared between the finite element model and physical experiments. The shear moduli at the initial and final regions of the stress–strain curve were greater within the lamellae than across the interlamellar layer. The difference between interlamellar and lamellar shear was greater at the outer anterior AF than at the inner anterior region. The finite element model was shown to accurately predict the global shear behavior or the AF. Future studies incorporating finite element analysis of the interlamellar compartment may be useful for predicting its physiological mechanical behavior to inform the study of its mechanobiology.

An Inverse Method to Measure the Complex Dynamic Moduli of Elastomers

2002 ◽  
Author(s):  
Yves H. Berthelot ◽  
Lei Wu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Simulations ◽  
Material Properties ◽  
Inverse Method ◽  
Element Model ◽  
Surface Velocity ◽  
Complex Dynamic ◽  
Dynamic Moduli ◽  
Large Defect

The dynamic moduli of elastomers are estimated from measurements of the surface velocity of a 3D sample. The measured values are matched with predictions from a finite element model in which the material properties are adjustable parameters. The sensitivity of the inversion technique to the locations of the measurements is discussed. Numerical simulations indicate that the method might be used to determine the moduli of two isotropic layers bonded together. Results also indicate the possibility of detecting the presence of a large defect in the sample.

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