FEM Analysis of the Collapse Strength of a Tube

1986 ◽  
Vol 108 (2) ◽  
pp. 158-164 ◽  
Author(s):  
K. Tokimasa ◽  
K. Tanaka
Keyword(s):  
Residual Stress ◽  
Fem Analysis ◽  
Plastic Collapse ◽  
Round Tube ◽  
Collapse Pressure ◽  
Hardening Behavior ◽  
Collapse Strength ◽  
Inner Surface ◽  
Plastic Hardening ◽  
New Formula

Using the FEM program, the effects of geometry, residual stress and the elasticplastic behavior of material on the collapse strength of a tube is analyzed and the following results are obtained. The plastic collapse pressure is maximum when the circumferential residual stress on the inner surface is tensile and is equal to 0.7σy. The plastic collapse pressure of a perfectly round tube can be approximately estimated by the following equation independent of the plastic-hardening behavior of the material: P = 2σ0.04 (D/t − 1)/(D/t)2. Based on these FEM results, a new formula is presented to evaluate the collapse strength of a tube.

Examination of Commercial Casing Collapse Strength Under Axial Loading

1982 ◽  
Vol 104 (4) ◽  
pp. 343-348 ◽  
Author(s):  
T. Tamano ◽  
Y. Inoue ◽  
H. Mimura ◽  
S. Yanagimoto
Keyword(s):  
Axial Load ◽  
Axial Stress ◽  
Axial Loading ◽  
External Pressure ◽  
Plastic Collapse ◽  
Slight Effect ◽  
Collapse Pressure ◽  
Minimum Value ◽  
Collapse Strength ◽  
Casing Collapse

Collapse testing of commercial API grade 7-in. casing was conducted under combined external pressure and axial load. The measured collapse pressure was considerably higher than the API minimum value, especially for the large D/t ratio, as expected. For the casings of large D/t ratio, the measured collapse pressure was a little smaller than the theoretical value for ideal pipe and the axial stress had a slight effect on the collapse pressure. In the range of plastic collapse, the measured collapse pressure was not less than the yield pressure for ideal pipe except near the boundary of the elastic and plastic collapse ranges.

Experimental Study on the Effect of Axial Tension Load on the Collapse Strength of Oilwell Casing

1982 ◽  
Vol 22 (05) ◽  
pp. 609-615 ◽  
Author(s):  
T. Kyogoku ◽  
K. Tokimasa ◽  
H. Nakanishi ◽  
T. Okazawa
Keyword(s):  
Experimental Data ◽  
Theoretical Analysis ◽  
Testing Machine ◽  
External Pressure ◽  
Tension Stress ◽  
Plastic Collapse ◽  
Collapse Pressure ◽  
Axial Tension ◽  
Collapse Strength ◽  
Tension Load

Abstract This paper discusses a newly developed collapse testing machine that permits investigation of practical performances of oilwell casings. Although a theoretical performances of oilwell casings. Although a theoretical analysis has shown that "axial tension stress has no effect on collapse pressure in the elastic case," this theory is not applied to the design of casing string because of lack of useful experimental data or authorized recommendation. To investigate the effect of axial tension load, full-size commercial casings have been tested under combined loading of axial tension load and external pressure. From the experimental results, the theory mentioned was proved in the case of so-called high-collapse casing, which has been used widely in recent years. Also shown is the applicable d/h range, which is wider than API's elastic collapse range. If the results of this experiment were applied to the design of a casing program, an economical and safe one could be obtained. program, an economical and safe one could be obtained. Introduction Recently, improved drilling techniques have permitted deeper and deeper oil and gas wells. As well depth increases, steel pipes for well casings receive greater external pressure and axial tension load because of the weight of the casing string. High-collapse casing, which has higher collapse strength per unit weight, has become easily available. To select and to design casing for such wells properly and economically, estimating collapse strength of the casing under axial tension load is very important. Much research and many experiments concerning collapse problems on casing, drillpipe, and tubing has been conducted by 1939. A theoretical analysis showed that axial tension stress lowers the collapse pressure in the case of plastic collapse and that axial tension stress has no effect on collapse pressure in the elastic case. Although collapse tests under axial tension load simulating oilwell casing in service were conducted on 2-in.-OD tubings, the theory for the effect of axial tension stress in the elastic collapse had not been proved sufficiently. There are few published experimental proved sufficiently. There are few published experimental data on collapse strength under axial tension load. In 1968, API summarized the collapse data and showed the formulas for collapse pressure and for collapse pressure under axial tension stress in the case of plastic collapse. The purpose of our study is to show how the collapse strength of commercial casings with large OD's behaves under the axial tension load, especially in the case of elastic collapse. To test the large-size casings, a multipurpose collapse testing machine that can simulate the service condition of oilwell casing has been developed. Statement of the Problem The collapse strength of casings under combined external pressure and axial tension load may be calculated from pressure and axial tension load may be calculated from Ref. 6's Formula 1.1.5.1: ....................(1) SPEJ p. 609

Residual Stress Evaluation of Ni Based Weld Metal Using Neutron Diffraction Method

2006 ◽  
Vol 524-525 ◽  
pp. 697-702 ◽  
Author(s):  
Shinobu Okido ◽  
Hiroshi Suzuki ◽  
K. Saito
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Neutron Diffraction ◽  
Weld Metal ◽  
Diffraction Method ◽  
Fem Analysis ◽  
Butt Weld ◽  
Stress Evaluation ◽  
Neutron Diffraction Method

Residual stress generated in Type-316 austenitic stainless steel butt-weld jointed by Inconel-182 was measured using a neutron diffraction method and compared with values calculated using FEM analysis. The measured values of Type-316 austenitic stainless steel as base material agreed well with the calculated ones. The diffraction had high intensity and a sharp profile in the base metal. However, it was difficult to measure the residual stress at the weld metal due to very weak diffraction intensities. This phenomenon was caused by the texture in the weld material generated during the weld procedure. As a result, this texture induced an inaccurate evaluation of the residual stress. Procedures for residual stress evaluation to solve this textured material problem are discussed in this paper. As a method for stress evaluation, the measured strains obtained from a different diffraction plane with strong intensity were modified with the ratio of the individual elastic constant. The values of residual stress obtained using this method were almost the same as those of the standard method using Hooke’s law. Also, these residual stress values agreed roughly with those from the FEM analysis. This evaluation method is effective for measured samples with a strong texture like Ni-based weld metal.

scholarly journals OS0820 Plastic collapse strength and maximum load evaluation method of flawed stainless piping subjected to axial tension and bending

2012 ◽  
Vol 2012 (0) ◽  
pp. _OS0820-1_-_OS0820-2_
Author(s):  
Seiji YANAGIHARA ◽  
Masaaki MATSUBARA ◽  
Ryousuke SUZUKI ◽  
Masato SUZUKI ◽  
Taisuke SHIRAISHI ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Maximum Load ◽  
Plastic Collapse ◽  
Axial Tension ◽  
Collapse Strength ◽  
Load Evaluation

Damage Evolution of the Interphase on C/SiC Composites with CZM Method

2012 ◽  
Vol 166-169 ◽  
pp. 2847-2850
Author(s):  
Yan Jun Chang ◽  
Zhuo Li ◽  
Ke Shi Zhang
Keyword(s):  
Residual Stress ◽  
Damage Evolution ◽  
Fem Analysis ◽  
Matrix Crack ◽  
Thermal Residual Stress ◽  
Analysis Model ◽  
Initial Matrix ◽  
Thermal Residual Stresses ◽  
Initiation And Propagation ◽  
Sic Composites

Considering thermal residual stress and initial matrix crack, the cylinder FEM analysis model for C/SiC tow was established. The cohesive element and damage criterions were introduced to simulation the initiation and propagation of interphase crack processes of C/SiC composites. The thermal residual stresses release with the initial matrix crack and the cracking on interphase. The interphase crack length was dominated by the performance of interphase. Analysis demonstrated that the CZM model can simulate well the thermal residual stress and the delamination of the interphase.

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