An Experimental Evaluation of the Stresses in Drilled Balls

1975 ◽  
Vol 97 (3) ◽  
pp. 533-537 ◽  
Author(s):  
L. J. Nypan ◽  
H. H. Coe ◽  
H. W. Scibbe
Keyword(s):  
Principal Stress ◽  
Strain Gage ◽  
Experimental Evaluation ◽  
Applied Load ◽  
Full Scale ◽  
Mass Reduction ◽  
Bending Stresses

Stresses in dimensionally similar large models of 40-, 50- and 60-percent mass reduction cylindrically hollow “drilled” bearing balls were experimentally evaluated with flat strain gage rosettes. Dimensionless principal stress coefficients were calculated and were applied to estimate the bending stresses in the drilled balls of three series of full-scale bearing experiments. Stresses were highest when the applied load approached the edge of the hole, and ranged up to almost 620 × 106 N/m2 (90,000 psi) at the bore.

Measurement of the Damping of Engineering Materials During Flexural Vibration at Elevated Temperatures

1944 ◽  
Vol 11 (2) ◽  
pp. A86-A92
Author(s):  
Carl Schabtach ◽  
R. O. Fehr
Keyword(s):  
Strain Gage ◽  
Modulus Of Elasticity ◽  
Tuning Fork ◽  
Elevated Temperatures ◽  
Flexural Vibration ◽  
Logarithmic Decrement ◽  
Vibration Frequencies ◽  
Bending Stresses ◽  
Engineering Materials

Abstract The method and equipment developed and used by the authors for measuring the damping of materials are described. A tuning-fork specimen is set into vibration by jerking a spreader from the gap between the ends of the tines. The damping is expressed in terms of the logarithmic decrement of the decaying vibration, which is measured and recorded by means of a magnetic oscillograph, amplifiers, and a resistance-type electric strain gage cemented to the specimen. The results include (1) the damping of a number of materials during flexural vibration at approximately 1000 cycles per sec, at maximum bending stresses up to 40,000 psi, and at temperatures up to 1400 F; (2) the variation in modulus of elasticity with temperature, as determined from the specimen vibration frequencies.

Testing facility for experimental evaluation of non-structural components under full-scale floor motions

2009 ◽  
Vol 18 (4) ◽  
pp. 387-404 ◽  
Author(s):  
Gilberto Mosqueda ◽  
Rodrigo Retamales ◽  
Andre Filiatrault ◽  
Andrei Reinhorn
Keyword(s):  
Experimental Evaluation ◽  
Full Scale ◽  
Structural Components ◽  
Testing Facility

An Application of Two Step Stress Classification Approach (Primary Structure Method) for Stress Classification at Cylindrical Shell–Nozzle Intersections Subjected to Internal Pressure, Radial Load and In- and Out-of-Plane Bending Moments

2015 ◽  
Author(s):  
Anindya Bhattacharya ◽  
Sachin Bapat ◽  
Hardik Patel ◽  
Shailan Patel
Keyword(s):  
Primary Structure ◽  
Applied Load ◽  
Element Analysis ◽  
Primary Stress ◽  
Stress Classification ◽  
Out Of Plane ◽  
Bending Stresses ◽  
Work Done ◽  
Simple Stress

Stress classification at shell and nozzle interface had always been an interesting and challenging problem for Engineers. Basic shell theory analyses shell stresses as membrane with local bending stresses developed at locations of discontinuity and load applications. Since in a shell structure, bending stresses develop to mainly maintain compatibility of deformation and membrane stresses to equilibrate the applied load, a simple stress classification will be to categorize the bending stresses as secondary stresses. This is because by definition, secondary stresses develop to maintain compatibility of deformation and primary stresses develop to maintain equilibrium with the applied load. This simplified analysis can result in errors as in real world 100% primary stress as well as 100% secondary stress is rare if not impossible [15], [16]. The widespread use of Finite Element Analysis has made this problem become even more challenging. Several researchers have addressed the problems of stress classification. References [1], [2], [3], [4], [5[, [6], [11], [12] can be consulted for additional details. In this paper the work done by Chen and Li [1], using the two step primary structure method has been used to analyse the problem of stress classification of a shell and nozzle. The spirit of the method has been retained, but several FE models have been made with some deviations from the method in ref.[1], to meaningfully arrive at primary structures.

Stress Classification at Cylindrical Intersections Using Primary Structure Method: A Parametric Study Using Finite Element Method

2016 ◽  
Author(s):  
Anindya Bhattacharya ◽  
Shailan Patel ◽  
Sachin Bapat ◽  
Michael P. Cross ◽  
Hardik Patel
Keyword(s):  
Finite Element ◽  
Primary Structure ◽  
Degrees Of Freedom ◽  
Applied Load ◽  
Original Model ◽  
Space Curve ◽  
Element Analysis ◽  
Primary Stress ◽  
Stress Classification ◽  
Bending Stresses

Stress classification at shell and nozzle interface has always been an interesting and challenging problem for Engineers. Basic shell theory analyses shell stresses as membrane with local bending stresses developed at locations of discontinuity and load applications. Since in a shell structure, bending stresses develop to mainly maintain compatibility of deformation and membrane stresses to equilibrate the applied load, a simple stress classification will be to categorize the bending stresses as secondary stresses. This is because by definition, secondary stresses develop to maintain compatibility of deformation and primary stresses develop to maintain equilibrium with the applied load. This simplified analysis can result in errors as in real world 100% primary stress as well as 100% secondary stress is rare if not impossible. The widespread use of Finite Element Analysis has made this problem become even more challenging. In this paper the work done by Chen and Li [1], using the two step primary structure method has been used to analyze the problem of stress classification of a shell and nozzle. This paper is a continuation of the author’s previous work on this topic [21]. In the previous paper, the sensitivity of modelling and the effect of the same on the results were investigated. However, the various approaches adapted in the paper [21], were not exactly in the true spirit of the method i.e in all the models, stresses in the vessels and nozzles were checked separately and compared against the stresses in the vessel and nozzle in the original model where by “original “model we mean the model with the vessel and nozzle modelled together i.e. connected along the space curve of intersection in all six degrees of freedom. The spirit of the method requires that the comparison has to be with reference to maximum M+B stresses in the original and reduced structure ( a “reduced” structure means where the vessel and the nozzle are not connected along some degrees of freedom along the space curve of intersection) and not individually in the vessels and nozzles and the M+B stresses have to be evaluated anywhere on the structure and not just at and close to the space curve of intersection. It is because of these reasons that [21] in not exactly in spirit of the method. In other words, the development of this paper was motivated by the fact that the previous paper did not use the exact spirit of the method and hence to investigate how its exact implementation changes results. This is the approach followed in this paper. A point to note; not in spirit of the method does not necessarily mean that the approach taken in [21] was not correct. It’s just that it was not in line with the way this method was defined by Chen and Li [1] and the present authors used their subjective approach to the problem. Additionally, this paper investigates the effect of geometric parameters like D/T, d/t and t/T on the results which was not investigated in the previous paper.

On Introducing” Section Modulus for Asymmetric Bending” of Stiffeners

2008 ◽  
Vol 45 (01) ◽  
pp. 9-20
Author(s):  
Lyuben D. Ivanov
Keyword(s):  
Geometric Property ◽  
Applied Load ◽  
Structural Profile ◽  
Section Modulus ◽  
Bending Stresses ◽  
Asymmetric Bending

ABSTRACT A new geometric property of shipbuilding structural profiles is introduced to consider asymmetric bending. This is the so-called section modulus for asymmetric bending, which allows for determining the total bending stresses in the structural profile for any angle of the attached plate and any angle of the plane of the applied load. As for symmetric bending, the major assumption behind the developed procedure for calculating the section modulus for asymmetric bending is that the structural profile works as a unit, that is, independently.

Stresses in a Cylindrical Shell Due to Nozzle or Pipe Connection

1945 ◽  
Vol 12 (2) ◽  
pp. A107-A112
Author(s):  
G. J. Schoessow ◽  
L. F. Kooistra
Keyword(s):  
Cylindrical Shell ◽  
Axial Compression ◽  
Strain Gage ◽  
Cylindrical Shells ◽  
Bending Moments ◽  
Compression Loading ◽  
Axial Tension ◽  
Transverse Bending ◽  
Bending Stresses ◽  
Tension Loading

Abstract Results are reported of a strain-gage test conducted on a 54-in-diam cylindrical shell to which was attached two 12-in-diam pipes. The pipes were subjected to direct axial-tension loading, direct axial-compression loading, and transverse bending moments. This construction simulates the conditions which exist in boiler drums, pressure piping, hydraulic penstocks, etc., where pipe connections are subject to forces and moments that develop strains in the shell to which the pipes are attached. Moderate loading applied to the pipes resulted in 20,000-psi bending stresses in the shell. These stresses are of a magnitude that demands the respect and attention of the designers. By publication of these data, the authors hope to stimulate interest in further experimental and analytical investigations of the problem, which eventually will establish a basis for predicting the magnitude of stresses in cylindrical shells. Such data are not now available.

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