Photo-Elastic Effects near the Centroid of Epoxy Specimens

2014 ◽  
Vol 875-877 ◽  
pp. 1572-1575
Author(s):  
Chiou Lin Liou ◽  
Chaur Jeng Wang
Keyword(s):  
Stress Concentration ◽  
Rapid Prototyping ◽  
Vacuum Chamber ◽  
Elastic Coefficient ◽  
Concentration Effects ◽  
Testing Specimen ◽  
Simply Supported ◽  
Significant Difference ◽  
Stress Concentration Effect ◽  
Actual Shape

The stress concentration of the circular hole within the mechanical mart can easily derived by the photo-elastic technique if the testing specimen is sufficiently developed. The testing specimen using the characteristic of the photo-elastic coefficient, with actual form like the mechanical part by rapid prototyping forming is thus used in this paper. The rapid mold for prototype is made by the RTV-2 silicone gel associated with the vacuum chamber to remove the air within it. The testing scheme is by way of the simply supported beam where the load is imposed on the middle of the specimen. Results show that the smaller diameter of hole on specimen provides a larger stress concentration effect. When the diameter of the hole is small, the stress concentration effects caused by the machined hole and the forming hole have almost no difference. However, the stress concentration effects of the larger diameter of the machined hole and of the formed hole give significant difference, the stress concentration caused by the machined hole is much greater than one of the formed hole. In this paper, the actual shape of the specimen which is as same as the original mechanical components can be quickly obtained by the rapid prototyping technology for the photoelastic technique to reveal the experimental mechanics of real applications.

Epoxy Specimen Fabricated by Rapid Prototyping Method for Photo-Elastic Technique

2010 ◽  
Vol 44-47 ◽  
pp. 2805-2808
Author(s):  
Chiou Lin Liou ◽  
Hsi Hsun Tsai
Keyword(s):  
Stress Concentration ◽  
Rapid Prototyping ◽  
Circular Hole ◽  
Elastic Coefficient ◽  
Concentration Effects ◽  
Testing Specimen ◽  
Mechanical Part ◽  
Significant Difference ◽  
Stress Concentration Effect ◽  
Actual Shape

Stress concentration due to the circular hole within the mechanical part is concerned during design phase. The stress concentration of the circular hole within the mechanical mart can easily derived by the photo-elastic technique if the testing specimen is sufficiently developed. The testing specimen using the characteristic of the photo-elastic coefficient, with actual form like the mechanical part by rapid prototyping forming is thus used in this paper. The rapid mold for prototype is made by the RTV-2 silicone gel associated with the vacuum chamber to remove the air within it. Totally twelve specimens divided into two sets, the first set with the machined holes by milling at the centroid of the specimens with diameters of 5, 8, 10, and 12 mm. The second set with the formed holes by molding with the previous diameters. The testing scheme is by way of the simply supported beam where the load is imposed on the middle of the specimen. Results show that the smaller diameter of hole on specimen provides a larger stress concentration effect. When the diameter of the hole is small, the stress concentration effects caused by the machined hole and the forming hole have almost no difference. However, the stress concentration effects of the larger diameter of the machined hole and of the formed hole give significant difference, the stress concentration caused by the machined hole is much greater than one of the formed hole. In this paper, the actual shape of the specimen which is as same as the original mechanical components can be quickly obtained by the rapid prototyping technology for the photoelastic technique to reveal the experimental mechanics of real applications.

scholarly journals Flexural Strength of Ice on Temperate Lakes

1977 ◽  
Vol 19 (81) ◽  
pp. 247-256 ◽  
Author(s):  
Anthony J. Gow
Keyword(s):  
Stress Concentration ◽  
Thermal Degradation ◽  
Flexural Strength ◽  
Coarse Grained ◽  
Cantilever Beams ◽  
Lake Ice ◽  
Simply Supported ◽  
Fine Grained ◽  
Stress Concentration Effect ◽  
Structural Imperfections

AbstractLarge, simply supported beams of temperate lake ice generally yield significantly higher f1exural strengths than the same beams tested in the cantilever mode. Data support the view that a significant stress concentration may exist at the fixed corners of the cantilever beams. Maximum effects are experienced with beams of cold, brittle ice substantially free of structural imperfections; the stress concentration factor may exceed 2.0 in this kind of ice. In ice that has undergone extensive thermal degradation the stress concentration effect may be eliminated entirely. Simply supported beams generally test stronger when the top surface is placed in tension. This behavior is attributed to differences in ice type; the fine-grained, crack-free top layer of snow-ice usually reacting more strongly in tension than the coarse-grained bottom lake ice which is prone to cracking.

Shear lag effect on stress concentration in simply-supported stiffened box girder

2021 ◽  
Vol 183 ◽  
pp. 106715
Author(s):  
Eiki Yamaguchi ◽  
Naoto Kittaka ◽  
Buchit Maho ◽  
Piti Sukontasukkul
Keyword(s):  
Stress Concentration ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Box Girder ◽  
Simply Supported ◽  
Lag Effect

Enhancing weak magnetic field MME coupling in NdFeB magnet/piezoelectric composite cantilevers with stress concentration effect

2021 ◽  
Vol 118 (13) ◽  
pp. 132902
Author(s):  
Zhonghui Yu ◽  
Zhaoqiang Chu ◽  
Jikun Yang ◽  
Mohammad Javad Pourhosseini Asl ◽  
Zhanmiao Li ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Stress Concentration ◽  
Weak Magnetic Field ◽  
Concentration Effect ◽  
Piezoelectric Composite ◽  
Ndfeb Magnet ◽  
Stress Concentration Effect

Calculation of stress-concentration factors for grooved shafts in bending using the point-matching technique

1973 ◽  
Vol 8 (2) ◽  
pp. 113-118 ◽  
Author(s):  
G J Matthews ◽  
C J Hooke
Keyword(s):  
Stress Concentration ◽  
Numerical Technique ◽  
Pure Bending ◽  
Point Matching ◽  
Matching Technique ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Stress Concentration Effect ◽  
Axisymmetric Bodies ◽  
Good Agreement

A general numerical technique is presented for the solution of the problem of elastic bending of axisymmetric bodies. Results obtained by this method are compared with existing results for grooved and shouldered shafts in pure bending and good agreement is obtained in each case. Additional results are presented for the stress-concentration effect of flat-bottomed circumferential grooves in cylindrical shafts for which no experimental or analytical results are available.

Theoretical Modeling of Steel Strip Reinforced Flexible Pipe With Swaging End Fitting by Taking Into Account Stress Concentration Effect

2019 ◽  
Author(s):  
Yifan Gao ◽  
Wei Chen ◽  
Yong Bai
Keyword(s):  
Stress Concentration ◽  
Internal Pressure ◽  
Steel Strip ◽  
Displacement Discontinuity ◽  
Concentration Effect ◽  
Elastic Model ◽  
Thin Wall ◽  
Burst Strength ◽  
Joint Area ◽  
Stress Concentration Effect

Abstract A new theoretical model was proposed to calculate the burst pressure of steel strip reinforced flexible composite pipes (steel strip PSP) based on the thin wall cylindrical shell theory and the squeeze pressure expression between layers was derived. The radial displacement discontinuity of pipe wall in pipe-end fitting joint area takes in account in this model which could result in Stress Concentration Effect (SCE) in reinforcement layers. The SCE is caused by swaging end fitting clamped tightly at the end of the pipe. The result of the hoop strain in the joint area calculated by this model is greater than the one calculated by the classic elastic model, which leads to relative conservative burst strength of the pipe. The hoop stress variation via internal pressure on innermost reinforcement layer is introduced to predict the burst strength of the pipe. As the stress in the joint area reaches its ultimate strength, the strain on the same layer in the point far away from this area (x→∞) is extracted and the corresponding internal pressure is obtained as the burst strength of the pipe. The calculated data from two models were compared with the experiment results and the proposed new model showed better accuracy than the classic elastic model. Final additional parametric studies were conducted, while the effect of the pipe diameter, the winding angle, the number and thickness of the reinforcement layer on the burst strength of the pipe were studied. Useful conclusions were drawn for the design and application of the steel strip PSP in offshore engineering.

An Engineering Basis for Establishing Radiographic Acceptance Standards for Porosity in Steel Weldments

1965 ◽  
Vol 87 (4) ◽  
pp. 887-893 ◽  
Author(s):  
H. Greenberg
Keyword(s):  
Stress Concentration ◽  
Nondestructive Testing ◽  
Pressure Vessel ◽  
Maximum Size ◽  
Theoretical Studies ◽  
Concentration Effects ◽  
Close Proximity ◽  
Testing Techniques ◽  
Steel Welds ◽  
Made In

Radiographic acceptance standards, such as those found in the ASME Unfired Pressure Vessel Code are critically reviewed. Limits on the size and distribution of porosity in steel welds are analyzed from the viewpoint of susceptibility to failure in service. In large part, present standards for porosity appear to have been established on a “good workmanship” basis rather than on setting sound conservative limits for the maximum size, and distribution of flaws which can be tolerated without decreasing the reliability of the product. Radiographic acceptance standards in use today do not reflect the significant advances being made in (1) the fracture mechanics approach to designing for prevention of failure; (2) theoretical studies of the stress-concentration effects of holes in close proximity to one another; and (3) the possible use of complementary nondestructive testing techniques. Considerable emphasis is placed on the proposition that radiographic acceptance standards for weldments must be designed specifically for each particular application. Considerations applicable to welds in the 120-in-dia rocket motor case are cited as an example of how standards for acceptable porosity and inclusions can be established.

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