Simplified Sealing Test Procedure of Gaskets Based on Compressive Strain

2002 ◽  
Author(s):  
Takashi Kobayashi ◽  
Takahito Nishida ◽  
Yuki Yamanaka
Keyword(s):  
Environmental Concern ◽  
Compressive Strain ◽  
Test Procedure ◽  
Complex Loading ◽  
Testing Procedure ◽  
Leak Rate ◽  
Strain Diagram ◽  
Stress Strain ◽  
The North ◽  
Behavior Based

With the recent increase of safety and environmental concern, the estimation of leak rate of a gasketed flanged connection in piping systems is an important subject to be studied. In order to estimate the leak rate, the sealing behavior of a gasket must be known. Currently, evaluation methods of the sealing behavior are proposed in the North America and Europe independently. One of the problems is that the representations of the sealing behavior are rather complex in both the methods. Thus, gasket tests take a long time to perform and cost much. The authors have carried out investigations on the sealing behavior of compressed fiber sheet gaskets and have shown that the leak rate is uniquely determined by the compressive strain of gasket. This fact makes the test procedure much easier eliminating complex loading-unloading sequences. A simplified leak testing procedure, in which a simple one-way loading is employed, has proposed. Furthermore, an equation for the sealing behavior of gasket, in which the effect of dimensions of gaskets is taken into consideration, has proposed. In this study, investigations on the sealing behaviors are overviewed first. Then, it is shown that the conventional sealing behavior based on the gasket stress is easily obtained from the sealing behavior based on the gasket strain and the stress-strain diagram of gasket. Both the sealing behavior and the stress-strain diagram of gasket are expressed by equations in this method. Finally, it has also shown that the sealing behavior obtained by the simplified test can be fully converted to the ROTT (ROom Temperature Tightness Test) forms.

Consideration on the Representations of Sealing Behavior of Gaskets: Effects of the Internal Pressure and the Gasket Width

2003 ◽  
Author(s):  
Takashi Kobayashi ◽  
Takahito Nishida ◽  
Yuki Yamanaka
Keyword(s):  
North America ◽  
Internal Pressure ◽  
Evaluation Method ◽  
Environmental Concern ◽  
Evaluation Methods ◽  
Leak Rate ◽  
Piping System ◽  
Mathematical Form ◽  
The North ◽  
Recent Increase

With the recent increase of a safety and environmental concern, it is important to estimate the leak rate of gasketed flanged connections in piping system. In order to estimate the leak rate, the sealing behavior of a gasket must be known. Currently, evaluation methods of the sealing behavior are proposed in the North America and Europe independently. However, the effects of the internal pressure and the gasket width are not sufficiently considered in both the methods. We have already proposed an evaluation method of sealing behavior based on the gasket strain in a mathematical form, in which the internal pressure and the gasket width are considered. In this paper, the effects of the internal pressure and the gasket width on the leak rate are discussed by applying the evaluation method to ASME and JIS flanges. Comparing the estimated results with those of PVRC and CEN methods, problems are pointed out.

scholarly journals Horizontal Movement of Fast Ice in the North Water Area

1977 ◽  
Vol 19 (81) ◽  
pp. 547-554 ◽  
Author(s):  
Hajime Ito ◽  
Fritz Müller
Keyword(s):  
Sea Ice ◽  
Water Area ◽  
Physical Characteristics ◽  
Stress Strain ◽  
Horizontal Movement ◽  
The North ◽  
North Water ◽  
Fast Ice ◽  
External Forces

AbstractThe understanding of the horizontal movement of fast ice is important for applied sea-ice mechanics. A case study, carried out in conjunction with a polynya known as North Water, is presented in this paper. The displacements of the fast-ire arches which separate the polynya from the surrounding ice-covered sea, were measured and found to be small. It is, therefore, confirmed that these arches prevent the influx of large quantities of sea ice into the polynya. The results are then explained in terms of the external forces (wind and current), the stress- strain situations and some physical characteristics (temperature and thickness) which were measured simultaneously.

scholarly journals Stress-strain curve of concretes with recycled concrete aggregates: analysis of the NBR 8522 methodology

2017 ◽  
Vol 10 (3) ◽  
pp. 547-567 ◽  
Author(s):  
D. A. GUJEL ◽  
C. S. KAZMIERCZAK ◽  
J. R. MASUERO
Keyword(s):  
Test Procedure ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Load Test ◽  
Recycled Aggregates ◽  
Elastic Behavior ◽  
It Use ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Brazilian Standard

ABSTRACT This work analyses the methodology "A" (item A.4) employed by the Brazilian Standard ABNT 8522 (ABNT, 2008) for determining the stress-strain behavior of cylindrical specimens of concrete, presenting considerations about possible enhancements aiming it use for concretes with recycled aggregates with automatic test equipment. The methodology specified by the Brazilian Standard presents methodological issues that brings distortions in obtaining the stress-strain curve, as the use of a very limited number of sampling points and by inducing micro cracks and fluency in the elastic behavior of the material due to the use of steady stress levels in the test. The use of a base stress of 0.5 MPa is too low for modern high load test machines designed do high strength concrete test. The work presents a discussion over these subjects, and a proposal of a modified test procedure to avoid such situations.

Stress-Strain Relationship for Steel under Uniaxial Cyclic Loadings

2002 ◽  
Vol 5 (3) ◽  
pp. 143-151 ◽  
Author(s):  
Luís Calado ◽  
António Brito
Keyword(s):  
Complex Loading ◽  
Steel Structures ◽  
General Purpose ◽  
Loading Conditions ◽  
Stress Strain ◽  
Strain Relationship ◽  
Complete Failure ◽  
Loading Tests ◽  
Cyclic Loading Tests ◽  
Mathematical Relationships

The mechanical properties of steel in the inelastic range can generally be described by mathematical relationships. Many such constitutive relationships have been validated by static or uniaxial cyclic loading tests. Very few models have been substantiated by test results under complex loading conditions. For that reason, the implementation of such models in general purpose structural analysis programs for steel structures under seismic actions, is in some cases complex and in others impossible. This paper is concerned with a uniaxial non-linear model for structural steel under complex loading condition and with damage accumulation. The Giuffré, Menegoto and Pinto model was taken as a basis for the development of this model. The accuracy of the proposed numerical model was drawn with uniaxial cyclic experiments. Some numerical simulations are presented in order to illustrate the capabilities of the model for use as a stress-strain relationship for steel under uniaxial complex loading conditions up to the complete failure of the material.

scholarly journals A Mechanical Test Procedure for Avalanche Snow

1977 ◽  
Vol 19 (81) ◽  
pp. 489-497 ◽  
Author(s):  
S. L. McCabe ◽  
F. W. Smith
Keyword(s):  
Mechanical Test ◽  
Test Procedure ◽  
Testing Machine ◽  
Constant Strain Rate ◽  
Time Behavior ◽  
Stress Strain ◽  
Direct Measurements ◽  
Natural Snow ◽  
Relaxation Curves ◽  
Design Construction

AbstractThe design, construction and testing of a portable, constant strain-rate testing machine for determining the mechanical behavior of avalanche now is described. The machine is intended for use in determining the stress-strain-time behavior of low-density natural snow in the field. A technique for making direct measurements of strain in the snow sample is described and stress-strain curves are presented for strain-rates ranging from 0.5 to 5.0 × 10−5 s−1. The densities of the snow samples tested range from 186 to 335 kg m−3. Ultimate-strength data and relaxation curves are also presented.

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