Analysis of Class Evaluation in Ultrasonic Test on Pressure Vessel and Pipe Weld Seams

2016 ◽  
Author(s):  
Youwei Zhang ◽  
Yuqing Yang ◽  
Le Chen
Keyword(s):  
Tensile Strength ◽  
Pressure Vessel ◽  
Lateral Position ◽  
Ultrasonic Test ◽  
Butt Joints ◽  
Quality Classification ◽  
Straight Line ◽  
The Relationship ◽  
Weld Seams ◽  
Test Result

In the ultrasonic test of girth or longitudinal butt joints in boiler, pressure vessel and pipe, there are multiple defects perpendicular to the length of the weld in a straight line. It is inappropriate of considering only the two adjacent defects in a line in quality classification without considering the defects located in different depth while in same lateral position. Hereby, we make tensile strength test of the rectangle samples with different numbers of side drilled holes, then do collection and analysis about the test result, so that we can get the relationship between elongation and tensile strength of the specimen under external force.

Size Effect on Mechanical Properties of LVL

2014 ◽  
Vol 887-888 ◽  
pp. 824-829
Author(s):  
Qing Fang Lv ◽  
Ji Hong Qin ◽  
Ran Zhu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Size Effect ◽  
Tensile Test ◽  
Compression Test ◽  
Test Results ◽  
Laminated Veneer Lumber ◽  
Object Of Study ◽  
The Relationship

Laminated veneer lumber is taken as an object of study, and use LVL specimens of different sizes for compression test and tensile test. The goal of the experiment is to investigate the size effect on compressive strength and tensile strength as well as the influence of the secondary glued laminated face, which appears in the secondary molding processes. The results show that both compressive strength and tensile strength have the size effect apparently and the existence of the secondary glued laminated face lower the compressive strength of LVL specimens. Afterwards, the relationship between compressive strength and volume along with tensile strength and area are obtained by the test results.

Relationship between physical and mechanical properties of accelerated weathering and outdoor weathering of PVC-coated membrane material under tensile stress

2016 ◽  
Vol 47 (2) ◽  
pp. 197-210 ◽  
Author(s):  
Xudong Yang ◽  
Xiuting Jiang ◽  
Jiyong Hu ◽  
Fangjuan Wang ◽  
Chun Hu
Keyword(s):  
Tensile Strength ◽  
Physical And Mechanical Properties ◽  
Accelerated Weathering ◽  
Membrane Material ◽  
Whiteness Index ◽  
Carbonyl Index ◽  
Tensile Stresses ◽  
The Relationship ◽  
Coated Membrane ◽  
Outdoor Weathering

To estimate the photo-oxidation aging performance of PVC-coated membrane material in atmospheric conditions under tensile stresses, the relationship between physical and mechanical properties under accelerated weathering test and outdoor weathering test is studied with the same cumulative UV radiation energy. And then, both tensile strength and whiteness index were measured and compared to characterize the property change of membrane material after aging under four different tensile stresses (0%, 5%, 10% and 20% of the breaking strength), respectively. In addition, FTIR spectrometry was applied to characterize the chemical components of the samples under different weathering conditions, and the carbonyl index was extracted. The results show that there were significant differences of tensile strength and carbonyl index between two kinds of aging conditions, whereas with the increasing tensile stresses, the whiteness index represented a consistent increasing deviation of accelerated weathering from the outdoor weathering. However, the relationship have been built between both whiteness index and tensile strength retention of accelerated weathering and those of outdoor weathering conditions after a Schwarzschild’s modification. Therefore, the service lifespan of PVC-coated membrane materials can be evaluated by accelerated weathering tests under tensile stresses.

Visual event-related potential studies supporting the validity of VARK learning styles' visual and read/write learners

2016 ◽  
Vol 40 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Sarawin Thepsatitporn ◽  
Chailerd Pichitpornchai
Keyword(s):  
Learning Styles ◽  
Event Related Potential ◽  
Term Memory ◽  
Objective Evidence ◽  
Subjective Evidence ◽  
The Right ◽  
Picture Superiority ◽  
The Relationship ◽  
Test Result ◽  
P200 Amplitude

The validity of learning styles needs supports of additional objective evidence. The identification of learning styles using subjective evidence from VARK questionnaires (where V is visual, A is auditory, R is read/write, and K is kinesthetic) combined with objective evidence from visual event-related potential (vERP) studies has never been investigated. It is questionable whether picture superiority effects exist in V learners and R learners. Thus, the present study aimed to investigate whether vERP could show the relationship between vERP components and VARK learning styles and to identify the existence of picture superiority effects in V learners and R learners. Thirty medical students (15 V learners and 15 R learners) performed recognition tasks with vERP and an intermediate-term memory (ITM) test. The results of within-group comparisons showed that pictures elicited larger P200 amplitudes than words at the occipital 2 site ( P < 0.05) in V learners and at the occipital 1 and 2 sites ( P < 0.05) in R learners. The between-groups comparison showed that P200 amplitudes elicited by pictures in V learners were larger than those of R learners at the parietal 4 site ( P < 0.05). The ITM test result showed that a picture set showed distinctively more correct responses than that of a word set for both V learners ( P < 0.001) and R learners ( P < 0.01). In conclusion, the result indicated that the P200 amplitude at the parietal 4 site could be used to objectively distinguish V learners from R learners. A lateralization existed to the right brain (occipital 2 site) in V learners. The ITM test demonstrated the existence of picture superiority effects in both learners. The results revealed the first objective electrophysiological evidence partially supporting the validity of the subjective psychological VARK questionnaire study.

Reinforcement Possibilities of Round Timber Bolted Joints

2014 ◽  
Vol 1082 ◽  
pp. 359-364
Author(s):  
Kristýna Klajmonová ◽  
Antonín Lokaj
Keyword(s):  
Tensile Strength ◽  
Civil Engineering ◽  
Bolted Joints ◽  
Steel Plates ◽  
Mechanical Reinforcement ◽  
With Screws ◽  
Test Result ◽  
Round Timber ◽  
Rate Of Improvement

In this article the results of round timber bolted joints with inserted steel plates tests are presented. First, unreinforced round timber specimens were tested. Mechanical reinforcement by using modified washers, steel bands, BOVA plates and boost with screws of round timber specimens based on test result was then proposed. Reinforced specimens of various densities were then tested and rate of improvement in tensile strength was established for each of five proposed reinforcement methods. Tests were carried out on EU100 pressure machine in Faculty of Civil Engineering of VŠB-TUO Ostrava.

scholarly journals Microstructural and Fracture Surface Study of Friction Stir Welded AA5082-AA7075 Butt Joints

2020 ◽  
Vol 5 (1) ◽  
pp. 49-56
Author(s):  
Gaurav Kumar ◽  
◽  
Rajeev Kumar ◽  
Ratnesh Kumar
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Fracture Surface ◽  
Microstructural Analysis ◽  
Butt Joints ◽  
Friction Stir ◽  
Three Samples ◽  
Mode Of Failure ◽  
Microstructural Behavior ◽  
Scanning Electron

In this study, experiments were performed to analyze the fracture surface and microstructural behavior of friction stir welded (FSW) AA5082-AA7075butt joints. Three samples at varying speeds and constant feed were prepared to identify optimum tool speed to produce FSW AA5082-AA7075 butt joints having maximum tensile strength and fatigue life. A scanning electron microscope (SEM) was used to analyze microstructure and fracture surfaces. The samples prepared exhibited a considerable difference in their fatigue life and tensile strength. Microstructural analysis showed the refinement of grains present in the stir zone (SZ), also known as the weld nugget, and thermo-mechanically affected zone (TMAZ). The study of the fracture surface showed that the mode of failure was ductile in nature

scholarly journals AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Friction Coefficient ◽  
Critical Stress ◽  
Friction Angle ◽  
Strength Properties ◽  
Brazilian Tensile Strength ◽  
The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

scholarly journals Fatigue Performance of Thin Laser Butt Welds in HSLA Steel

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1499
Author(s):  
Patricio G. Riofrío ◽  
Fernando Antunes ◽  
José Ferreira ◽  
António Castanhola Batista ◽  
Carlos Capela
Keyword(s):  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Hsla Steel ◽  
High Strength ◽  
Butt Joints ◽  
Factors Affecting ◽  
Weld Profile ◽  
The Relationship ◽  
Good Agreement ◽  
Significant Factors

This work is focused on understanding the significant factors affecting the fatigue strength of laser-welded butt joints in thin high-strength low-alloy (HSLA) steel. The effects of the weld profile, imperfections, hardness, and residual stresses were considered to explain the results found in the S-N curves of four welded series. The results showed acceptable fatigue strength although the welded series presented multiple-imperfections. The analysis of fatigue behavior at low stress levels through the stress-concentrating effect explained the influence of each factor on the S-N curves of the welded series. The fatigue limits of the welded series predicted through the stress-concentrating effect and by the relationship proposed by Murakami showed good agreement with the experimental results.

scholarly journals Strength Attainment of Geopolymer Concrete with GGBS at Ambient Curing

2019 ◽  
Vol 9 (2S2) ◽  
pp. 56-59
Keyword(s):  
Tensile Strength ◽  
Ambient Temperature ◽  
Sodium Hydroxide ◽  
Cross Sections ◽  
Strength Properties ◽  
Industrial Wastes ◽  
Mix Design ◽  
Geopolymer Concrete ◽  
Ambient Curing ◽  
Test Result

Geopolymer concrete plays a major role in concrete industry by replacing cement and using the industrial wastes. In this study, the cement is completely replaced by GGBS and strength properties are analyzed. An M30 mix design is prepared and the specimens are cast and tested. For this, sodium hydroxide and sodium silicate are used as activator and its ratio is fixed as 1:2.5. Sodium hydroxide of 12 molarity, 550kg/m3 of GGBS is used in the study. Admixture La Hypercrete S25 (HTS code 38244090) is added in the mix by 1% of weight of GGBS to obtain the required workability. For compression study, cubes in 100 mm size are cast. Cylinders with 100mm dia and 200mm height are tested for splitting tensile strength and beam specimens of 500mm long and 100mm cross sections were cast for determining the flexure behaviour. The beams are subjected to ambient curing and tested at 3, 7, 14, 28 and 56 days. The test result shows that there is a gradual increment in all the strengths from 3 to 56 days and it proves that geopolymer concrete with GGBS cured at ambient temperature performs well in the strength properties.

scholarly journals Tensile Properties and Damping Capacity of Cold-Rolled Fe-20Mn-12Cr-3Ni-3Si Damping Alloy

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5975
Author(s):  
Jae-Hwan Kim ◽  
Jong-Min Jung ◽  
Hyunbo Shim
Keyword(s):  
Tensile Strength ◽  
Cold Rolling ◽  
Tensile Properties ◽  
Volume Fraction ◽  
High Strength ◽  
Damping Capacity ◽  
Austenite Stability ◽  
Ε Martensite ◽  
Cold Rolled ◽  
The Relationship

The tensile properties and damping capacity of cold-rolled Fe–20Mn–12Cr–3Ni–3Si alloys were investigated. The martensitic transformation was identified, including surface relief with a specific orientation and partial intersection. Besides, as the cold rolling degree increased, the volume fraction of ε-martensite increased, whereas α’-martensite started to form at the cold rolling degree of 15% and slightly increased to 6% at the maximum cold rolling degree. This difference may be caused by high austenite stability by adding alloying elements (Mn and Ni). As the cold rolling degree increased, the tensile strength linearly increased, and the elongation decreased due to the fractional increment in the volume of martensite. However, the damping capacity increased until a 30% cold rolling degree was approached, and then decreased. The irregular tendency of the damping capacity was confirmed, depicting that it increased to a specific degree and then decreased as the tensile strength and elongation increased. Concerning the relationship between the tensile properties and the damping capacity, the damping capacity increased and culminated, and then decreased as the tensile properties and elongation increased. The damping capacity in the high-strength area tended to decrease because it is difficult to dissipate vibration energy into thermal energy in alloys with high strength. In the low-strength area, on the other hand, the damping capacity increased as the strength increased since the increased volume fraction of ε-martensite is attributed to the increase in the damping source.

scholarly journals Technical Basis for Master Curve for Fatigue Crack Growth of Ferritic Steels in High-Pressure Gaseous Hydrogen in ASME Section VIII-3 Code

2019 ◽  
Author(s):  
Chris San Marchi ◽  
Joseph Ronevich ◽  
Paolo Bortot ◽  
Yoru Wada ◽  
John Felbaum ◽  
...  
Keyword(s):  
High Pressure ◽  
Tensile Strength ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Pressure Vessel ◽  
Master Curve ◽  
Gaseous Hydrogen ◽  
Section Viii ◽  
Crack Growth Rates

Abstract The design of pressure vessels for high-pressure gaseous hydrogen service per ASME Boiler and Pressure Vessel Code Section VIII Division 3 requires measurement of fatigue crack growth rates in situ in gaseous hydrogen at the design pressure. These measurements are challenging and only a few laboratories in the world are equipped to make these measurements, especially in gaseous hydrogen at pressure in excess of 100 MPa. However, sufficient data is now available to show that common pressure vessel steels (e.g., SA-372 and SA-723) show similar fatigue crack growth rates when the maximum applied stress intensity factor is significantly less than the elastic-plastic fracture toughness. Indeed, the measured rates are sufficiently consistent that a master curve for fatigue crack growth in gaseous hydrogen can be established for steels with tensile strength less than 915 MPa. In this overview, published reports of fatigue crack growth rate data in gaseous hydrogen are reviewed. These data are used to formulate a two-part master curve for fatigue crack growth in high-pressure (106 MPa) gaseous hydrogen, following the classic power-law formulation for fatigue crack growth and a term that accounts for the loading ratio (R). The bounds on applicability of the master curve are discussed, including the relationship between hydrogen-assisted fracture and tensile strength of these steels. These data have been used in developing ASME VIII-3 Code Case 2938. Additionally, a phenomenological term for pressure can be added to the master curve and it is shown that the same master curve formulation captures the behavior of pressure vessel and pipeline steels at significantly lower pressure.

Sign in / Sign up

Export Citation Format

Share Document