scholarly journals An Ultrasonic Technique for Axial Bolt-Stress Determination

1987 ◽  
pp. 1549-1557 ◽  
Author(s):  
Albert C. Holt ◽  
Bruce Cunningham ◽  
George C. Johnson ◽  
David Auslander
Keyword(s):  
Ultrasonic Technique ◽  
Stress Determination ◽  
Bolt Stress

Development of a Protocol to Determine the Minimum Operating Stress of Compressed Non-Asbestos Gaskets

2013 ◽  
Author(s):  
Ana C. Silva ◽  
Gabriele Rodrigues ◽  
Lucas Xavier
Keyword(s):  
New Method ◽  
Test Results ◽  
Flange Joint ◽  
Stress Determination ◽  
Complex Approach ◽  
Bolt Stress ◽  
Operating Stress ◽  
Bolted Flange ◽  
Minimum Operating

The ASME PCC-1-2010 Guidelines for Pressure Boundary Bolted Flange Joint Assembly [1] introduced a new method for an appropriate assembly bolt stress determination across bolted flange connections. The method introduced in APPENDIX O of the ASME PCC-1-2010 has recently received substantial attention by several gasket researchers. In this new method, calculation is based in a complex approach that considers the integrity of each joint component. However, almost no information is found about some essential parameters. Therefore, the intent of the present study is to introduce a protocol for the determination of one of these factors: the minimum gasket operating stress (Sgmin-o). This value is defined as “the gasket stress that should be maintained on the gasket during operation in order to assure the leakage does not occur”. This paper will show a detailed study for a protocol to determine the minimum gasket operating stress and actual test results for compressed non-asbestos gaskets. Furthermore, the device used in the research will be defined in detail afterwards.

Physical and Elastic Properties of Mixed Alkali Borate Glasses Using Ultrasonic Technique

2011 ◽  
Vol 3 (9) ◽  
pp. 429-431
Author(s):  
P.Vasantharani P.Vasantharani ◽  
◽  
N. Sangeetha N. Sangeetha
Keyword(s):  
Elastic Properties ◽  
Borate Glasses ◽  
Ultrasonic Technique ◽  
Mixed Alkali ◽  
Alkali Borate Glasses

A Practical Ultrasonic Inspection Method for Detecting and Characterising Defects Found Within Composite Repairs

2018 ◽  
Author(s):  
J Downing ◽  
A Hook
Keyword(s):  
Wall Thickness ◽  
Steel Substrate ◽  
Ultrasonic Method ◽  
Ultrasonic Inspection ◽  
Heat Exposure ◽  
Matrix Cracking ◽  
Ultrasonic Technique ◽  
Inspection Method ◽  
Composite Repairs ◽  
Layered Matrix

Two steel substrate test panels were developed to represent common plate thicknesses found on naval vessels and scanned using the Babcock developed ultrasonic technique. One sample comprised of a series of slotted surface breaking flaws of varying widths and through thicknesses to represent fracturing/cracking. The inspection method detected simulated cracking to a depth of 2mm and 0.5mm in width. The second sample included numerous loss of wall thickness areas of varying diameters and through thicknesses, with the smallest detectable loss of wall thickness being 0.1mm at a 15mm diameter. After proving confidence in detection, there was a need to characterise flaws to provide support and ascertain a repair action. Samples were produced that were subjected to either impact or heat exposure to induce realistic representative damage. The practical ultrasonic method was successfully used to independently characterise between the samples, with induced de-laminations caused by blisters, and multi layered matrix cracking caused by varying levels of projectile impacts, due to their unique morphology.

On the method of ultrasonic control of mechanical stresses

2018 ◽  
Vol 84 (7) ◽  
pp. 62-66
Author(s):  
K. V. Kurashkin
Keyword(s):  
Elastic Wave ◽  
Orientation Distribution ◽  
Elastic Wave Velocity ◽  
Mechanical Stresses ◽  
Material Structure ◽  
Stress Determination ◽  
Welded Steel ◽  
Ultrasonic Control ◽  
Cubic Crystallites ◽  
Proportional Relationship

A method of ultrasonic control of the mechanical stresses which takes into account the heterogeneity of the material structure and does not require unloading of the structure or using reference samples is considered. The procedure is based on echo-method of measuring time of the bulk elastic wave propagation and determination of the relative values ν31 and ν32 related to the material structure and mechanical stresses. It is shown that stresses violate the linearity of the relationship observed between the parameters in the absence of the mechanical stresses in the rolled material. This effect formed a basis for developing a method of the deviator stress determination. The purpose of the study is to demonstrate the main advantages of the developed method against the known ultrasonic techniques used for evaluation of the mechanical stresses, give theoretical grounds to the effect which allows taking into account the heterogeneity of the material structure, and also to exemplify the procedure. An analytical expression is derived using bulk elastic wave velocity in an orthotropic material composed of cubic crystallites and an assumption on the existence of simple proportional relationship between the coefficients of the orientation distribution function in rolled metal. Presented results of the mathematical modeling confirm the experimentally observed linear dependence between the parameters ν31 and ν32 in the absence of mechanical stresses. The results of evaluating residual stresses in a welded steel plate are presented as an example of the applicability of the developed procedure. Data of ultrasonic technique and data of strain gage measurements are compared. The features of the described method of stress determination are marked and the applicability limits are specified.

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