Theoretical and experimental investigations of the stress state of elastic cylinders with grooves

1983 ◽  
Vol 19 (10) ◽  
pp. 862-866
Author(s):  
Yu. N. Nemish ◽  
Yu. I. Vologzhaninov ◽  
A. I. Zirka ◽  
N. M. Bloshko
Keyword(s):  
Stress State ◽  
Experimental Investigations ◽  
Elastic Cylinders

Geklebte Schneidsegmente im unterbrochenen Schnitt*/Adhesively bonded cutting segments in intermittent cutting – Examples for their application in circular sawing of aluminum

2018 ◽  
Vol 108 (06) ◽  
pp. 466-472
Author(s):  
M. Stroka ◽  
F. Schumpp ◽  
M. Schneider
Keyword(s):  
Stress State ◽  
Experimental Investigations ◽  
Turning Process ◽  
Adhesively Bonded ◽  
The Real ◽  
Circular Saw ◽  
Circular Sawing ◽  
Sawing Process ◽  
Intermittent Cutting ◽  
Model Approach

Der Beitrag stellt Untersuchungen zu geklebten Schneidsegmenten für Kreissägeanwendungen vor. Die tatsächliche Beanspruchung des Sägeprozesses wird dabei durch einen Modellversuch abgebildet, der den Sägeprozess auf einen Drehprozess mit unterbrochenem Schnitt überträgt. So können mit geringem Aufwand vereinfachte, geklebte Proben in der Zerspanung anwendungsbezogen untersucht werden. Die Versuche wurden mit hartmetallbestückten Proben an Aluminiumwerkstücken durchgeführt.   The article presents experimental investigations of adhesively bonded cutting segments for circular saw blades. The real stress state is reproduced by a model approach which transfers the sawing process to a turning process with intermittent cutting. This allows for easily investigating the use of adhesively bonded specimens in machining. The experiments were performed with carbide-tipped specimens on aluminum workpieces.

scholarly journals Influence of grinding zones on the tooth root bending strength of case carburized gears

2021 ◽  
Author(s):  
Karl Jakob Winkler ◽  
Thomas Tobie ◽  
Karsten Stahl
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Bending Strength ◽  
Decisive Role ◽  
Experimental Investigations ◽  
Tooth Root ◽  
Industrial Practice ◽  
Application Range ◽  
Residual Stress State ◽  
Root Area

AbstractKnowledge of the expected tooth root bending strength plays a decisive role in the design of gear sets. Due to dimensional and shape changes resulting from distortion due to the heat treatment, unintentional, partial grinding in the tooth root area may occur, particularly in the application range of large gears. The influences of an unintentional grinding zone on the tooth root bending strength have not yet been clarified with sufficient accuracy. As a result, grinding zones lead to uncertainties when evaluating the tooth root bending strength and thus to a loss of time and cost in the field of industrial practice.This paper presents experimental investigations on the influence of grinding zones on the tooth root bending strength of case carburized gears. For the experimental investigations, there are three unground reference variants with different blasting treatments: non-blasted, mechanical cleaned by shot blasting and shot peened. The unground reference variants are examined regarding their tooth root bending strength. For the other test gear variants, different grindings zones are applied resulting in light and strong material removal by grinding. The variants with the different grinding zones are examined analogously regarding their tooth root bending strength and are subsequently compared to the reference variants.The results of the experimental investigations show that grinding zones can have diverse influences on the tooth root bending strength of case carburized gears– Non-blasted gears do not show changes regarding the tooth root bending strength with regard to light or strong grinding zones applied within this investigation.– Shot blasted (mechanical cleaned) gears show no change in the tooth root bending strength for light grinding zones (grinding application does not significantly alter the original residual stress state in the tooth root area).– Shot blasted (mechanical cleaned) gears show a reduction of the tooth bending strength of up to 20 % with regard to strong grinding zones (grinding application does significantly alter the original residual stress state in the tooth root area).– Shot peened gears show a behavior similar to that of shot blasted gears with reductions of the tooth root bending strength of up to 30 %.– Shot peening the strong grinding zones as a repair measure can increase the reduced tooth root bending strength again. However, for the investigated test gears, the resulting tooth root bending strength was below the shot blasted reference variant.The results of this paper help to evaluate the influence of grinding zones on the tooth root bending strength of case carburized gears more precisely compared to the generalized reductions of current standards and classifications. The results can be incorporated in standards such as DIN 3390 as well as ISO 6336 and can be applied in the field of industrial practice. Eventually, the findings help to reduce the current loss of time and cost caused by uncertainties regarding grinding zones.

scholarly journals Precision analysis of forced-oscillation device: numerical modelling and experimental investigations

2020 ◽  
Vol 17 (6) ◽  
pp. 980-992
Author(s):  
Hui Li ◽  
Jing Lin ◽  
Jinghuai Gao ◽  
Yanbin He ◽  
Dehua Han ◽  
...  
Keyword(s):  
Stress State ◽  
Forced Oscillation ◽  
Simulated Data ◽  
Static Friction ◽  
Experimental Investigations ◽  
Frequency Dependent ◽  
Large Measurement ◽  
Solid Foundation ◽  
Large Measurement Error ◽  
Elastic Characteristics

Abstract Investigating the stress state of a sample-standard column in forced-oscillation apparatus is critical to clearly quantify measurement credibility, offering insights into revealing intrinsic frequency-dependent elastic characteristics of a rock sample. To investigate the effects of the jointing condition, the location of strain gauges and device resonance on the stress state of a sample-standard column, we experiment with a typical forced-oscillation setup numerically and experimentally at frequencies of 2–800 Hz. Overall, the numerical model captures the primary features of the forced-oscillation device, which makes the simulated data fit well with the measured results. Meanwhile, based on the configuration of the sample-standard column with variable static friction in jointing contacts, the simulated results also indicate that mechanical contacts of the sample-standard-vibrator assembly lead to stress concentration, resulting in coordinate-dependent strains on both the sample and standard. Additionally, strain magnitude is also frequency-dependent, causing a relatively large measurement error on the elasticity of the sample at higher frequencies. Ultimately, numerical results not only optimize measurement workflow but also create a solid foundation for the interpretation of measured data.

scholarly journals Numerical and experimental assessment of the long-operated drill pipes destruction conditions

2020 ◽  
pp. 88-97
Author(s):  
O. Yu. Vytyaz ◽  
R. S. Hrabovskyi ◽  
V. I. Artym ◽  
V. V. Tyrlych ◽  
N. R. Hrabovska
Keyword(s):  
Stress Intensity ◽  
Stress State ◽  
Limit State ◽  
Drill Pipe ◽  
Crack Tip ◽  
Experimental Investigations ◽  
Technical Diagnostics ◽  
Drilling Fluids ◽  
Critical Crack ◽  
Drill Pipes

The cause of failures in the elements of the drill string when drilling deep wells is the occurrence and development of crack-like defects in the cross section. The generalized data of defectoscopy of long-term operated drill pipes conducted at the Ukrburgaz drilling rigs from 2015 to 2017, as well as numerous literature data show that such defects are formed at the bottom of corrosion ulcers that occur during operation under the influence of workloads and drilling fluids, in particular during tripping operations, both on the inner and outer surfaces of the drill pipe. During the tripping operations, under the influence of tensile loads, they being developed go up to the surface of the drill pipe, forming scouring, which ultimately leads to the destruction of the pipe. Using known analytical solutions, the stress state in the vicinity of the semieliptic crack located on both the outer and inner surfaces of the hollow cylinder under axial load was estimated and the corresponding stress intensity coefficients at the crack tip of these defects were determined. To predict the limit state of a drill pipe with a semieliptic crack, the analysis of crack parameters reflecting the local stress-strain state near the crack tip is performed. Using the finite-element method, the stress state around the vertex of the semieliptic crack was determined and on this basis the characteristics of fracture mechanics were calculated: J – integral and stress intensity coefficients. Diagrams of fracture risk assessment in the coordinates "depth of crack-like defect - depth of drilling - stress intensity factor" are offered, which make it possible to estimate the safe depth of both internal and external semieliptic crack-like defects detected by technical diagnostics taking into account results of experimental investigations of critical crack resintance. The admissible sizes of the studied defects depending on the depth of drilling are determined.

Theoretical and Experimental Investigations of an Elasto-Plastic Circular Contact Bounded by Real Rough Surfaces

2003 ◽  
Author(s):  
Dorel Prodan ◽  
Emanuel Diaconescu
Keyword(s):  
Stress State ◽  
Pressure Distribution ◽  
Plastic Material ◽  
Surface Finishing ◽  
Experimental Investigations ◽  
Surface Microtopography ◽  
Laser Profilometry ◽  
Residual Deformations ◽  
Numerical Program ◽  
Circular Contact

To investigate the pressure distribution and the stress state in a real elasto-plastic circular contact, bearing balls of two different degrees of surface finishing were used. These were pressed against a polished flat surface made of softer steel. The surface microtopography data measured in each case by a laser profilometry was introduced in a numerical program developed to evaluate the pressure distribution, stress state and residual deformations for an elasto-plastic material with non-linear hardening. The dimension of calculated contact plastic deformations compare favorably with those found experimentally by aid of a laser profilometer.

Estimation of the Load Carrying Capacity of the Bellows Compensator for Gas Pipelines in the Areas of Mining Production

2020 ◽  
Author(s):  
Volodymyr Stryzhalo ◽  
Maksym Zarazovskii ◽  
Andrii Bohdan ◽  
Zakhar Yaskovets ◽  
Vitalii Antonchenko
Keyword(s):  
Stress State ◽  
Stress Reduction ◽  
Large Scale ◽  
Mining Industry ◽  
Experimental Investigations ◽  
Gas Pipelines ◽  
Mine Production ◽  
Rupture Pressure ◽  
Production Areas ◽  
Ground Displacements

Abstract The stress state of pipelines in areas of mine production requires obligatory consideration the influence of ground displacements. In this case the rules for design pipelines include the additional actions, such as the wall thickness increasing or U-shaped compensators installation. The Ukrainian coal mining industry requires the expanding of mine production areas. It leads to the situation where old pipelines, which are not designed for such loads, could rupture due to ground displacements. The principle of “extinguish a fire” is applied in this case. It consists in applying of stress reduction actions before certain stage of mine production (so-called lava), such as digging out long sections, cutting and sanding, which require the involvement of significant human and material resources. But, in some cases, even the large-scale application of these actions does not lead to the stress reduction to the acceptable level (especially for pipelines of diameter less then 200mm). So, to solve this problem the implementation of bellow compensators (BC) is proposed. The present work consists of: • experimental investigations of BC which are carried out in order to obtain its bearing capacity and to validate its designed parameters guaranteed by the manufacturer; • simulation of the BC loading process using FEM with adjusting the way of contact modelling between the BC layers in such manner, to be best correlate with the results of experiments; • the application of obtained results for modelling of stress state of real pipelines in the areas of coal mine production. The results of experimental investigation of BC of DN100 is presented. Their include: hydrotest with axial displacements limitation; tension-compression cycles for different values of amplitude with simultaneously loading of the operating value of gas pipeline internal pressure; rupture pressure determination. Based on the experimental results, numerical modelling and specified domestic software for stress state assessment in pipelines the optimal locations and the required number of BCs is determined for buried gas pipelines. The results of presented works allowed us not only to implement the BCs to gas pipelines DN100 in areas of mine productions, but also the necessary experience for creation of larger diameters BCs is obtained.

scholarly journals Tests for equivalence of the stress state and the generalized stress-strain diagram babbitt Tin-based.

2014 ◽  
Vol 2014 (3) ◽  
pp. 26-34 ◽  
Author(s):  
Михаил Зернин ◽  
Mikhail Zernin
Keyword(s):  
Stress State ◽  
Experimental Investigations ◽  
Stress And Strain ◽  
Strain Diagram ◽  
Stress Strain ◽  
Different Types

Describes the methodologies and results of experimental investigations on the basis of tin babbitt in different types of stress. Specification of parameters of the criterion of equivalence of states of stress and strain diagram obtained single babbitt.

Short Stress State Questionnaire

2015 ◽  
Vol 31 (1) ◽  
pp. 20-30 ◽  
Author(s):  
William S. Helton ◽  
Katharina Näswall
Keyword(s):  
Stress State ◽  
Factor Structure ◽  
Human Performance ◽  
Self Report ◽  
Confirmatory Factor ◽  
Stress States ◽  
Related Stress ◽  
Using Data ◽  
Task Conditions ◽  
Multiple Samples

Conscious appraisals of stress, or stress states, are an important aspect of human performance. This article presents evidence supporting the validity and measurement characteristics of a short multidimensional self-report measure of stress state, the Short Stress State Questionnaire (SSSQ; Helton, 2004 ). The SSSQ measures task engagement, distress, and worry. A confirmatory factor analysis of the SSSQ using data pooled from multiple samples suggests the SSSQ does have a three factor structure and post-task changes are not due to changes in factor structure, but to mean level changes (state changes). In addition, the SSSQ demonstrates sensitivity to task stressors in line with hypotheses. Different task conditions elicited unique patterns of stress state on the three factors of the SSSQ in line with prior predictions. The 24-item SSSQ is a valid measure of stress state which may be useful to researchers interested in conscious appraisals of task-related stress.

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