FINITE‐ELEMENT COMPUTATION OF SEISMIC ANOMALIES FOR BODIES OF ARBITRARY SHAPE

Geophysics ◽  
1976 ◽  
Vol 41 (1) ◽  
pp. 145-150 ◽  
Author(s):  
Bruce A. Bolt ◽  
Warwick D. Smith
Keyword(s):  
Finite Element ◽  
Arbitrary Shape ◽  
Plane Waves ◽  
Surface Profile ◽  
Massive Sulfide ◽  
Spectral Ratios ◽  
Element Analysis ◽  
S Waves ◽  
Ore Bodies ◽  
Upward Moving

A method which uses observed frequency spectral ratios of seismic plane waves for exploration of ore bodies is now available. The new method is based on the numerical solution of the response of a two‐dimensional shallow structural anomaly to an upward‐moving seismic wave from a distant earthquake or explosion. Finite‐element analysis is used for both P- and S-waves. Solutions to the direct problem for bodies of arbitrary shape have not previously been available. Results in the time and frequency domains are discussed here for a salt ridge and for a massive sulfide body. For the inverse problem, interpretation using contours of spectral ratios along a surface profile is suggested.

THE EFFECT OF ASPHERICITY OF ACETABULAR BEARING SURFACE ON CONTACT MECHANICS OF UHMWPE TOTAL HIP IMPLANTS BY FINITE ELEMENT ANALYSIS

2017 ◽  
Vol 17 (01) ◽  
pp. 1750011 ◽  
Author(s):  
XUAN ZHANG ◽  
LING WANG ◽  
XIFENG PENG ◽  
DICHEN LI ◽  
JIANKANG HE ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Mechanics ◽  
Contact Pressure ◽  
Surface Profile ◽  
Surface Measurement ◽  
Element Analysis ◽  
Actual Surface ◽  
Total Hip ◽  
Measuring Machine

Asphericity and out-of-roundness are generally used to evaluate the manufacturing quality of ultra-high molecular weight polyethylene (UHMWPE) cup inner surfaces, which can potentially affect initial clinical wear and contribute to osteolysis of total hip arthroplasty. This study measured the location and magnitude of asphericity and the out-of-roundness value for four UHMWPE cups in a single set, and then investigated the effects of the asphericity on the contact mechanics of UHMWPE cups. A co-ordinate measuring machine (CMM) was used for the surface measurement and finite element analysis (FEA) was adopted for contact mechanics study. The results demonstrated that the asphericity varied between cups with the maximum value as 0.088[Formula: see text][Formula: see text][Formula: see text]0.004[Formula: see text]mm. Although such a value met the ISO specification, large difference of volume appeared for the asphericity above 0.060[Formula: see text]mm. Actual surface profile accounting for the asphericity was found to affect the value of contact pressure and contact area by around 12%. The inferior asphericity resulted in a nonsmoothly distributed contact pressure, which had a negative effect on the contact mechanics of UHMWPE cups and the edge loading was predicted to occur for the sample with a large asphericity. In conclusion, the asphericity of UHMWPE cup could affect the contact mechanics of the articular bearings and may subsequently contribute to initial wear during bedding-in phase.

Effect of Orifice Shape in Contour Crafting with Ceramic Material: A Simulation for Extrusion and Deposition Mechanism

2007 ◽  
Vol 26-28 ◽  
pp. 953-956 ◽  
Author(s):  
Hong Kyu Kwon ◽  
Kwang Soo Kim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ceramic Material ◽  
Material Flow ◽  
External Surface ◽  
Surface Profile ◽  
Element Analysis ◽  
Deposition Mechanism ◽  
Contour Crafting ◽  
Optimal Fusion

This paper presents our experimentation and modeling efforts to study the pattern of material flow in the extrusion and deposition stages of the Contour Crafting (CC) process. Specifically, we performed a preliminary finite element analysis (FEA) of extrusion and deposition mechanisms with clay as the fabrication material. Using the FEA simulations, we derived certain basic understandings of the effect of extrusion orifice geometry on the performance of CC. We found that a square orifice is most aptly suited, both in terms of delivering the optimal fusion between layers as well as creating the desired external surface profile. Our experiments validate these results.

Integration of Laser Surface Scanning and Non-Linear Finite Element Analysis for the Assessment of Volumetric Corrosion in Pipeline Fittings

2014 ◽  
Author(s):  
Robert M. Andrews ◽  
Matthew Hadden ◽  
Paul Casson ◽  
Tamsin Kashap ◽  
Steven A. Johnstone
Keyword(s):  
Finite Element ◽  
Surface Profile ◽  
Initial Study ◽  
Large Strains ◽  
Fe Model ◽  
Element Analysis ◽  
Artificial Defect ◽  
Failure Pressure ◽  
Numerical Predictions ◽  
Non Linear

Methods for assessing volumetric corrosion in fittings such as bends or branch connections are not well developed, although limited guidance is given in some codes. For other components and cases where the corrosion profile is complex or there are large external loads, these methods cannot be applied. In addition, detailed analysis of the actual corrosion shape and the applied loads may demonstrate significant additional margins compared with the code method. To do this, the actual profile of the corroded shape is required. This paper reports an initial study investigating methods of non-contact scanning a corroded fitting, constructing a finite element (FE) model of the corroded shape and prediction of the failure pressure. Two corroded welded branch connections which had been removed from a block valve installation were used. The surface profiles were measured using a laser scanner and the scans imported into a FE model generation system and detailed models of the damaged connections then developed. Non-linear analyses were carried out to predict the failure pressure using assumed and measured stress-strain curves. Failure was predicted to occur in the area of the weld between the forged connection and the header. Hydrostatic burst tests were carried out on the connections. In both tests failure initiated in the header pipe remote from the branch and the corroded area, and as a result the failure pressures were below those predicted by the FEA. However, the failures did occur at pressures about 20% higher than the original hydrostatic test pressure. Strain gauge data from the pressure tests were in reasonable agreement with the numerical predictions. Large strains were predicted and measured in the large artificial defect introduced in the second test. This program has demonstrated the feasibility of making detailed surface profile measurements of corroded components on site, and then using these profiles in a non-linear FEA to predict failure pressures. The development work needed for routine application is discussed, and the selection of a failure criterion for the FEA when analysing complex geometries where there may be substantial through wall bending is also considered.

Reconstruction of Real Rough Surface Based on Fractal and the Study on Bolt Assemble Technique

2012 ◽  
Vol 248 ◽  
pp. 426-432 ◽  
Author(s):  
Wei Wang ◽  
Qiang Tang ◽  
Xiao Dong Xu ◽  
Shui Qing Gong ◽  
Xiao Peng Liu
Keyword(s):  
Finite Element ◽  
Rough Surface ◽  
Rough Surfaces ◽  
Surface Profile ◽  
Element Analysis ◽  
Fractal Characteristic ◽  
Fractal Models ◽  
Relationship Model ◽  
Bolt Connection ◽  
2D And 3D

Aiming at the importance of the microcosmic topography of connecting surface and bolt assembling technique to the bolt connection performance, the fractal characteristic of bolt joint rough surface is studied based on the power spectrum of its micro surface profile. Fractal models of 2D and 3D rough surfaces are presented by W-M function and the 2D and 3D bolt joint rough surfaces are reconstructed. Imageware and Pro/e are used to build the bolt connecting model based on the real rough surface presented by W-M function. The preload is imitated by the PREST179 element. The finite element transient analysis is used to imitate the speed and force size of the bolt tightening. The relationship model between tighten speed, preload size and connecting performance whose target is contact stress is presented based on the finite element analysis results. According the model, the single bolt precise assembling technique is obtained.

scholarly journals Finite Element Modeling of Mode I Failure of the Single Contoured Cantilever CFRP-Reinforced Concrete Beam

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
T. Nicholas ◽  
D. Boyajian ◽  
S. E. Chen ◽  
A. Zhou
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Surface Profile ◽  
Test Method ◽  
Reinforced Concrete Beams ◽  
Interface Fracture ◽  
Mode I ◽  
Cohesive Elements ◽  
Element Analysis ◽  
Laboratory Test Results

The single contour cantilever beam (SCCB) test method has been developed with the intent to capture Mode I opening failures of CFRP-reinforced concrete beams. Recent development in the method explores possible shifting damage into the concrete substrate by using the International Concrete Repair Institute (ICRI) Surface Profile Level Three (SP3) as the desired CFRP bonded interface to concrete. To validate and explain the interface fracture behavior, finite element analysis using special cohesive elements has been performed. The cohesive element allows separation of the concrete substrate from the CFRP. This paper presents the simulation of laboratory test results, where failure in the substrates has been successfully reproduced. The simulation results indicate that finite element method using cohesive elements can successfully replicate Mode I critical strain energy release rate and the peak capacity of the laboratory tests and may have the potential to simulate actual applications.

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