Sources and Consequences of Residual Stresses due to Welding

2014 ◽  
Vol 783-786 ◽  
pp. 2777-2785 ◽  
Author(s):  
Thomas Nitschke-Pagel ◽  
Klaus Dilger
Keyword(s):  
Residual Stresses ◽  
The Other ◽  
Production Factor ◽  
Other Hand ◽  
Welding Processes

A detrimental parameter which is always connected with welding processes is the distortion which may occur in welded components. The reduction of distortion is a very costly production factor and in complex constructions the disposal of the distortion might be very complicate or even impossible. On the other hand we know that every step which is done to increase the stiffness of a welded component in order to avoid distortion is connected with the possibility of the generation of higher tensile residual stresses.

Diamond Coatings for Machining: Coating Thickness Effects

2009 ◽  
Author(s):  
Feng Qin ◽  
Y. Kevin Chou ◽  
Dustin Nolen ◽  
Raymond G. Thompson
Keyword(s):  
Residual Stresses ◽  
Coating Thickness ◽  
Cutting Forces ◽  
Failure Modes ◽  
Cutting Tools ◽  
Cutting Edge ◽  
The Other ◽  
Diamond Coatings ◽  
Coated Tools ◽  
Other Hand

Chemical vapor deposition (CVD)-grown diamond films have found applications as a hard coating for cutting tools. Even though the use of conventional diamond coatings seems to be accepted in the cutting tool industry, selections of proper coating thickness for different machining operations have not been often studied. Coating thickness affects the characteristics of diamond coated cutting tools in different perspectives that may mutually impact the tool performance in machining in a complex way. In this study, coating thickness effects on the deposition residual stresses, particularly around a cutting edge, and on coating failure modes were numerically investigated. On the other hand, coating thickness effects on tool surface smoothness and cutting edge radii were experimentally investigated. In addition, machining Al matrix composites using diamond coated tools with varied coating thicknesses was conducted to evaluate the effects on cutting forces, part surface finish and tool wear. The results are summarized as follows. (1) Increasing coating thickness will increase the residual stresses at the coating-substrate interface. (2) On the other hand, increasing coating thickness will generally increase the resistance of coating cracking and delamination. (3) Thicker coatings will result in larger edge radii; however, the extent of the effect on cutting forces also depends upon the machining condition. (4) For the thickness range tested, the life of diamond coated tools increases with the coating thickness because of delay of delaminations.

scholarly journals Residual stress analysis, mechanical and metallurgical properties of dissimilar weldments of Monel 400 and AISI 316

2020 ◽  
Vol 111 (11) ◽  
pp. 880-893
Author(s):  
Balram Yelamasetti ◽  
G. Rajyalakshmi
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Analysis ◽  
Welded Joints ◽  
The Other ◽  
Metallurgical Properties ◽  
Monel 400 ◽  
Residual Stress Analysis ◽  
Aisi 316 ◽  
Welding Processes

Abstract This research manuscript explores the residual stress analysis, mechanical and metallurgical aspects of dissimilar welded joints between AISI 316 and Monel 400 developed by constant, pulse and Interpulse current TIG welding processes. The induced residual stresses have been measured experimentally by employing X-ray diffraction. The mechanical properties of welded joints have been determined by conducting tensile and Vickers hardness testing. The metallurgical properties of weldments have been analyzed by employing optical and scanning electron microscopy. From the experimental results, lower residual stresses have been observed in Interpulse current TIG weldment than the other two weldments. The tensile properties of the Interpulse current TIG weldment were observed to be higher than the other two weldments. In Interpulse TIG weldments, grain refinement and reduced heat affected zone near the fusion zone have been observed.

Effect of Pressure-Dependency of the Yield Criterion on the Development of Plastic Zones and the Distribution of Residual Stresses in Thin Annular Disks

2011 ◽  
Vol 78 (3) ◽  
Author(s):  
Sergei Alexandrov ◽  
Yeau-Ren Jeng ◽  
Evgenii Lomakin
Keyword(s):  
Stress Distribution ◽  
Residual Stresses ◽  
Yield Criterion ◽  
Circumferential Stress ◽  
The Other ◽  
Plastic Yielding ◽  
Annular Disk ◽  
Effect Of Pressure ◽  
Other Hand ◽  
Pressure Dependency

The main objective of the present paper is to show an effect of pressure-dependency of the yield criterion on the development of the plastic zone and the distribution of residual stresses in a thin annular disk subject to a pressure over its inner edge during the loading stage. The Drucker–Prager yield criterion is adopted to account for the effect of the hydrostatic pressure on plastic yielding. The state of stress is supposed to be plane and the material model is perfectly plastic. A semi-analytical stress solution to the problem formulated is given and its qualitative features are emphasized. It is shown that the pressure at which plastic yielding starts and the pressure at which the entire disk becomes plastic are weakly affected by the pressure-dependency of the yield criterion. On the other hand, this dependency has a significant effect on the maximum possible pressure that can be supported by the disk. The minimum pressure at which reverse yielding occurs is also affected by the pressure-dependency of the yield criterion. In general, the residual radial stress distribution is more influenced by the pressure-dependency of the yield criterion than the residual circumferential stress distribution, although the magnitude of circumferential stresses is larger than the magnitude of radial stresses. On the other hand, the effect of pressure-dependency of the yield criterion on the residual circumferential stress distribution is pronounced in the vicinity of the inner edge of the disk, where this stress is important for improving fatigue performance of structures.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

Don’t Put Me in This Group

2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke
Keyword(s):  
Positive Emotions ◽  
Negative Emotions ◽  
Negative Information ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Group Memberships

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.

ON THE OTHER HAND

1961 ◽  
Vol 6 (6) ◽  
pp. 222-223
Author(s):  
Edwin G. Boring
Keyword(s):  
The Other ◽  
Other Hand
Sign in / Sign up

Export Citation Format

Share Document