Fracture Assessment of the High Strength Super-Martensitic Stainless Steel Welds by SINTAP Defect Assessment Procedure

Author(s):  
A. K. Motarjemi ◽  
M. Koc¸ak ◽  
R. Segar ◽  
S. Riekehr

13% Cr supermartensitic stainless steel is an adequate substitute material for the conventional carbon and duplex stainless steel pipes for mild corrosive environments in the oil and gas industries. By development of these new steel and respective welding technologies, structural integrity analysis of the welded pipes, is essential and a challenging task. Depending on the welding process, filler wire used, the deformation and failure behaviours of the welded pipes could be different. In this study, fitness for service analysis verified with Submerged Arc welded Middle Tension, M(T), plates as well as for the reeling deformation during the pipe-laying process. This was done by applying analysis Levels 0, I, II and III of a recently developed European Structural Integrity Assessment Procedure (SINTAP). The goal was first of all to verify SINTAP’s load-carrying capacity predictions for welded M(T) specimens (wide plates) by comparing them with corresponding experimental data. SINTAP was also used for estimating the maximum tolerable crack size within the base or weld regions under about 2.7% applied strain, which is the strain equal to the reeling process. The estimated load-carrying capacity of the plates were found on the safe side with acceptable conservatism for all the SINTAP analysis Levels.

2008 ◽  
Vol 35 (7) ◽  
pp. 708-715 ◽  
Author(s):  
Curtis Berthelot ◽  
Erin Stuber ◽  
Diana Podborochynski ◽  
Jena Fair ◽  
Brent Marjerison

It has long been known that increased load-carrying capacity during the winter months is very beneficial to rural road transportation in Saskatchewan. However, it has been observed that rapid weakening of thin-paved roads during spring thaw is highly detrimental to the load-carrying capacity of these roads. Direct measures of the structural integrity of Saskatchewan roads as a function of seasonal changes have not been quantified in the past. The objective of this study was to directly quantify the impact frost action has on the load-carrying capacity of thin-surfaced roads. This study examined the magnitude and rate of change of in situ structural deflection responses of a typical Saskatchewan thin-surfaced road during fall freeze-up and spring thaw in 2006–2007. This study showed that structural deflection responses significantly improved with frost depth greater than 50 cm and that deflection response significantly worsened with minimal thaw depth, as expected. The data obtained also indicated a significant increase in nonlinear strain weakening behavior during fall freeze-up at frost depths less than 50 cm. Therefore, based on the findings of this study, the frost thickness and the rate of change in frost thickness need to be directly considered in the fall and in the spring when calculating seasonal load limits of thin-paved roads.


2018 ◽  
Vol 18 (1) ◽  
pp. 20-34 ◽  
Author(s):  
Shojaeddin Jamali ◽  
Tommy HT Chan ◽  
Andy Nguyen ◽  
David P Thambiratnam

For assessment of existing bridges, load rating is usually performed to assess the capacity against vehicular loading. Codified load rating can be conservative if the rating is not coupled with the field data or if simplifications are incorporated into assessment. Recent changes made to the Australian Bridge assessment code (AS 5100.7) distinguish the difference between design and assessment requirements, and include addition of structural health monitoring for bridge assessment. However, very limited guidelines are provided regarding higher order assessment levels, where more refined approaches are required to optimize the accuracy of the assessment procedure. This article proposes a multi-tier assessment procedure for capacity estimation of existing bridges using a combination of structural health monitoring techniques, advanced nonlinear analysis, and probabilistic approaches to effectively address the safety issues on aging bridges. Assessment of a Box Girder bridge was carried out according to the proposed multi-tier assessment, using data obtained from modal and destructive testing. Results of analysis at different assessment tiers showed that both load-carrying capacity and safety index of the bridge vary significantly if current bridge information is used instead of as-designed bridge information. Findings emerged from this study demonstrated that accuracy of bridge assessment is significantly improved when structural health monitoring techniques along with reliability approaches and nonlinear finite element analysis are incorporated, which will have important implications that are relevant to both practitioners and asset managers.


Author(s):  
Yang-chun Deng ◽  
Gang Chen

To reduce the waste of austenitic stainless steels due to their low yield strengths, the strain hardening technology is used to significantly improve their yield strength, in order to increase the elastic load carrying capacity of austenitic stainless steel pressure vessels. The basic principle of strain-hardening for austenitic stainless steel pressure vessels and two common models of strain hardening, including Avesta Model for ambient temperature and Ardeform Model for cryogenic temperature, were briefly introduced. However, it was fully established by experiments, the lack of a necessary theoretical foundation and the safety concern affect its widespread use. In this study, we investigated the load carrying capacity of strain-hardening austenitic stainless steel pressure vessels under hydrostatic pressure, based on the elastic-plastic theory. To understand the effects of strain hardening on material behavior, the plastic instability loads of a round tensile bar specimen were also derived under two different loading paths and validated by experiments. The results of theoretical, experimental and finite element analyses illustrated, considering the effect of material strain hardening and structural deformation, at ambient temperature, the static load carrying capacity of pressure vessels does not relate to the loading paths. To calculate the plastic instability pressures, a method was proposed so that the original dimension and original material parameters prior to strain hardening can be used either by the theoretical formula or finite element analysis. The safety margin of austenitic stainless steel pressure vessels under various strain hardening degrees was quantitatively analyzed by experiments and finite element method. A 5% strain as the restrictive condition of strain hardening design for austenitic stainless steel pressure vessels was suggested.


2021 ◽  
Vol 60 (1) ◽  
pp. 519-540
Author(s):  
Wenyuan Kong ◽  
Yongfa Huang ◽  
Zhan Guo ◽  
Xiaoyong Zhang ◽  
Yu Chen

Abstract This article reports the experimental behavior of square hollow stainless steel tubular trusses under static loading. A total of five specimens, including three trusses with K-joint, one truss with N-joint, and one truss with T-joint, were tested to study the effect of different outer widths of brace members and the types of joint on the flexural performance of square hollow stainless steel tubular trusses. The failure modes, flexural rigidity, load carrying capacity, ductility, load versus displacement curves, and load versus strain curves of all the tested specimens are presented. It can be seen that the chords of all specimens experienced surface plasticity. The test results indicate that the specimen with T-joint has the best ductility. The flexural rigidity of the truss with the K-joint is better than that of specimens with N-joint or T-joint. The flexural rigidity of trusses with the K-joint was found to increase with the increase of outer width (D) of the brace members varying from 38 to 80 mm. Besides, the load-carrying capacity per unit weight of the specimen with T-joint is better than that of specimens with N-joint or K-joint.


2014 ◽  
Vol 58 (5) ◽  
pp. 743-753
Author(s):  
Mitsuru Ohata ◽  
Shotaro Ueno ◽  
Takashi Namekata ◽  
Shigeki Satoh ◽  
Tsukasa Okazaki ◽  
...  

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.


2005 ◽  
Vol 10 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Z. Kala

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.


2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.


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