An Experimental Investigation of Deformation of Plated Holes for a Single 30-210-30°C Thermal Cycle

1994 ◽  
Vol 116 (1) ◽  
pp. 1-5 ◽  
Author(s):  
T. S. Gross ◽  
J. A. Perault ◽  
D. W. Watt
Keyword(s):  
Finite Element ◽  
Thermal Cycle ◽  
Compressive Strain ◽  
Large Diameter ◽  
Temperature Cycle ◽  
Finite Element Models ◽  
Elastic Analysis ◽  
Printed Wiring Board ◽  
Cross Sectional ◽  
Full Temperature

The out-of-plane displacement field around two plated holes with different pad diameters in an FR-4 printed wiring board was measured for a single 30°C–210°C–30°C temperature cycle using electro-optic holographic interferometry. At the end of the temperature cycle, the outside edge of the pad was raised above the level of the laminate and the inside edge was depressed below the level of the laminate. This indicates that the barrel is plastically deformed in compression to a total strain of approximately 0.58–0.66 percent which is well above typical yield strains of 0.2 percent. The smaller diameter pad was inclined more than the large diameter pad, but the residual compressive strain in the barrel was roughly the same. Both the residual compressive strain and the inward inclination of the pad are in conflict with the predictions of most finite element models of plated hole deformation. However, there were cracks at the pad-barrel interface which are not included in finite element models. The residual compressive deformation of the barrel is attributed to inelastic deformation of the FR-4 matrix at the high end of the thermal cycle. The stress in the barrel was estimated using an approximate elastic analysis of pad deflections. The estimated stress for different hole diameters for the same pad diameter was roughly proportional to the ratio of their barrel plating cross-sectional areas for a 30–150°C temperature change. The elastic analysis is shown to predict (unrealistic) tensile barrel stresses at the end of the full temperature cycle.

Strains and Deflections of GFRP Sandwich Panels Due to Uniform Out-of-Plane Pressure

2002 ◽  
Vol 39 (04) ◽  
pp. 223-231
Author(s):  
J. C. Roberts ◽  
M. P. Boyle ◽  
P. D. Wienhold ◽  
E. E. Ward
Keyword(s):  
Finite Element ◽  
Compressive Strain ◽  
Sandwich Panels ◽  
External Pressure ◽  
Woven Fabric ◽  
Core Material ◽  
Finite Element Models ◽  
Strain Gages ◽  
Glass Fiber Reinforced Plastic ◽  
Out Of Plane

Rectangular orthotropic glass fiber reinforced plastic sandwich panels were tested under uniform out-of-plane pressure and the strains and deflections were compared with those from finite-element models of the panels. The panels, with 0.32 cm (0.125 in.) face sheets and a 1.27 cm (0.5 in.)core of either balsa or linear polyvinylchloride foam, were tested in two sizes: 183 × 92 cm (72 × 36 in.) and121 × 92 cm (48 × 36 in.). The sandwich panels were fabricated using the vacuum-assisted resin transfer molding technique. The two short edges of the sandwich panels were clamped, while the two long edges were simply supported. Uniform external pressure was applied using two large water inflatable bladders in series. The deflection and strains were measured using dial gages and strain gages placed at quarter and half points on the surface of the panels. Measurements were made up to a maximum out-of-plane pressure of 0.1 MPa (15psi). A total of six balsa core and six foam core panels were tested. Finite-element models were constructed for the 183-cm-long panel and the121-cm-long panel. Correlation between numerical and experimental strains to deflect the sandwich panel was much better on the top (tensile) side of the panels than on the bottom (compressive)side of the panels, regardless of panel aspect ratio or core material. All sandwich panels exhibited the same compressive strain reversal behavior on the compressive side of the panel. This phenomenon was thought to be due to nonlinearly induced micro-buckling under the strain gages, buckling of the woven fabric, or micro-cracking within the resin.

Modelling of Rotating Twisted Blades as 1D Continuum

2016 ◽  
Vol 821 ◽  
pp. 183-190
Author(s):  
Jan Brůha ◽  
Drahomír Rychecký
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Beam Theory ◽  
Parameter Tuning ◽  
Finite Element Models ◽  
Cross Sectional ◽  
One Dimensional ◽  
Rayleigh Beam ◽  
Twisted Blade ◽  
Sectional Parameters

Presented paper deals with modelling of a twisted blade with rhombic shroud as one-dimensional continuum by means of Rayleigh beam finite elements with varying cross-sectional parameters along the finite elements. The blade is clamped into a rotating rigid disk and the shroud is considered to be a rigid body. Since the finite element models based on the Rayleigh beam theory tend to slightly overestimate natural frequencies and underestimate deflections in comparison with finite element models including shear deformation effects, parameter tuning of the blade is performed.

scholarly journals Electrical Capacitance Tomography (ECT) Electrode Size Simulation Study for Cultured Cell

2021 ◽  
Vol 2071 (1) ◽  
pp. 012052
Author(s):  
N A Zulkiflli ◽  
M D Shahrulnizahani ◽  
X F Hor ◽  
F A Phang ◽  
M F Rahmat ◽  
...  
Keyword(s):  
Finite Element ◽  
Cultured Cells ◽  
Electrical Capacitance Tomography ◽  
Finite Element Models ◽  
Capacitive Sensing ◽  
Electrical Capacitance ◽  
Cross Sectional ◽  
Electrode Size ◽  
Cell Monitoring ◽  
Capacitance Tomography

Abstract Cell sensing and monitoring using capacitive sensors are widely used in cell monitoring because of the flexible and uncomplicated design and fabrication. Previous work from many different fields of applications has integrated capacitive sensing technique with tomography to produce cross-sectional images of the internal dielectric distribution. This paper carried an investigation on the capabilities of four 16-channel sensor electrodes with different electrode sizes to detect the change in the dielectric distribution of the cultured cells. All three 16-channel sensor electrodes are designed and simulate on COMSOL 6.3a Multiphysics. The pre-processing results obtained from three finite element models (FEM) of ECT sensor configurations in detecting the cell phantom shows that bigger electrodes size are more sensitive to permittivity distribution.

scholarly journals High throughput phenotyping of cross-sectional morphology to assess stalk lodging resistance

Plant Methods ◽  
2022 ◽  
Vol 18 (1) ◽  
Author(s):  
Yusuf A. Oduntan ◽  
Christopher J. Stubbs ◽  
Daniel J. Robertson
Keyword(s):  
Finite Element ◽  
High Throughput ◽  
Plant Traits ◽  
Finite Element Models ◽  
Vascular Bundles ◽  
Lodging Resistance ◽  
Cross Sectional ◽  
Conium Maculatum ◽  
Finite Element Software ◽  
Stalk Lodging

Abstract Background Stalk lodging (mechanical failure of plant stems during windstorms) leads to global yield losses in cereal crops estimated to range from 5% to 25% annually. The cross-sectional morphology of plant stalks is a key determinant of stalk lodging resistance. However, previously developed techniques for quantifying cross-sectional morphology of plant stalks are relatively low-throughput, expensive and often require specialized equipment and expertise. There is need for a simple and cost-effective technique to quantify plant traits related to stalk lodging resistance in a high-throughput manner. Results A new phenotyping methodology was developed and applied to a range of plant samples including, maize (Zea mays), sorghum (Sorghum bicolor), wheat (Triticum aestivum), poison hemlock (Conium maculatum), and Arabidopsis (Arabis thaliana). The major diameter, minor diameter, rind thickness and number of vascular bundles were quantified for each of these plant types. Linear correlation analyses demonstrated strong agreement between the newly developed method and more time-consuming manual techniques (R2 > 0.9). In addition, the new method was used to generate several specimen-specific finite element models of plant stalks. All the models compiled without issue and were successfully imported into finite element software for analysis. All the models demonstrated reasonable and stable solutions when subjected to realistic applied loads. Conclusions A rapid, low-cost, and user-friendly phenotyping methodology was developed to quantify two-dimensional plant cross-sections. The methodology offers reduced sample preparation time and cost as compared to previously developed techniques. The new methodology employs a stereoscope and a semi-automated image processing algorithm. The algorithm can be used to produce specimen-specific, dimensionally accurate computational models (including finite element models) of plant stalks.

The Effect of Pressure on Burnthrough Susceptibility during in-Service Welding

2011 ◽  
Vol 121-126 ◽  
pp. 2313-2317 ◽  
Author(s):  
Wei Liu ◽  
Han Tao ◽  
Chao Wen Li ◽  
Guang Fei Guo ◽  
Guo Lin Gu
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Thermal Cycle ◽  
Temperature Limit ◽  
Inside Surface ◽  
Finite Element Models ◽  
Temperature Profiles ◽  
3D Finite Element ◽  
Effect Of Pressure

3D finite element models have been developed for X70 pipelines during the in-service welding. These models have been used to analyze the effects of internal pressure on the susceptibility of burnthrough. The work has showed that radial deflection could be regarded as a burnthrough limit. The same internal pressure has more important effect on the thinner materials and bigger diameter pipes. Internal pressure also has a great impact on the temperature profiles and the thermal cycle of inside surface. For thinner materials, Battelle’s 982°C temperature limit is overly conservative.

scholarly journals Finite Element Analysis of Reinforced Concrete Slabs with Spherical Voids

2013 ◽  
Vol 6 (4) ◽  
pp. 15-37
Author(s):  
Amer M. Ibrahim ◽  
Nazar K. Ali ◽  
Wissam D. Salman
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Compressive Strain ◽  
Strain Curve ◽  
Point Load ◽  
Concrete Slabs ◽  
Finite Element Models ◽  
Element Analysis ◽  
Reinforced Concrete Slabs ◽  
Spherical Voids

This paper presents a numerical analysis using ANSYS finite element program to simulate the reinforced concrete slabs with spherical voids when subjected to five point load. Six slabs with length 1.0m, width 1.0m, height (0.1m and 0.125m) and simply supported were modeled. Nonlinear materials behavior, as it relates to steel reinforcing bars and plain concrete, and linear behavior for steel plate is simulated using appropriate constitutive models. The results showed that the general behavior of the finite element models represented by the load-deflection curves at mid-span, ultimate load, load-maximum concrete compressive strain curve, and crack patterns show good agreement with the test data from the experimental test. The finite element models represented by this work can be used to carry out parametric study for the BubbleDeck slab specimens

scholarly journals Finite Element Study on Continuous Rotating versus Reciprocating Nickel-Titanium Instruments

2016 ◽  
Vol 27 (4) ◽  
pp. 436-441 ◽  
Author(s):  
Mohamed I. El-Anwar ◽  
Salah A. Yousief ◽  
Engy M. Kataia ◽  
Tarek M. Abd El-Wahab
Keyword(s):  
Finite Element ◽  
Low Cost ◽  
Nickel Titanium ◽  
Finite Element Models ◽  
Element Analysis ◽  
Cross Sectional ◽  
Design And Manufacturing ◽  
Cad Cam ◽  
Strain Stress ◽  
Sectional Shape

Abstract In the present study, GTX and ProTaper as continuous rotating endodontic files were numerically compared with WaveOne reciprocating file using finite element analysis, aiming at having a low cost, accurate/trustworthy comparison as well as finding out the effect of instrument design and manufacturing material on its lifespan. Two 3D finite element models were especially prepared for this comparison. Commercial engineering CAD/CAM package was used to model full detailed flute geometries of the instruments. Multi-linear materials were defined in analysis by using real strain-stress data of NiTi and M-Wire. Non-linear static analysis was performed to simulate the instrument inside root canal at a 45° angle in the apical portion and subjected to 0.3 N.cm torsion. The three simulations in this study showed that M-Wire is slightly more resistant to failure than conventional NiTi. On the other hand, both materials are fairly similar in case of severe locking conditions. For the same instrument geometry, M-Wire instruments may have longer lifespan than the conventional NiTi ones. In case of severe locking conditions both materials will fail similarly. Larger cross sectional area (function of instrument taper) resisted better to failure than the smaller ones, while the cross sectional shape and its cutting angles could affect instrument cutting efficiency.

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