Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 6
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

In order to provide sufficient cooling capacity for working and heading faces of the coal mine, chilled water is often transported a long distance along pipelines in deep mine, which inevitably results in its temperature rising owing to heat transfer through pipe wall and the friction heat for flow resistance. Through theoretical models for temperature increasing of the chilled water were built. It is pointed out that the temperature rising of the chilled water should be considered as a result of the synergy effects of the heat transfer and the friction heat, but theoretical analysis shows that within engineering permitting error range, the temperature increasing can be regarded as the sum caused by heat transfer and fraction heat respectively, and the calculation is simplified. The calculation analysis of the above two methods was made by taking two type of pipe whose diameters are De273 × 7 mm and De377 × 10 mm, with 15 km length in coal mine as an example, which shows that the error between the two methods is not over 0.04°C within the allowable error range. Aims at the commonly used chilled water diameter pipe, it is proposed that if the specific frictional head loss is limited between 100 Pa/m and 400 Pa/m, the proportion of the frictional temperature rising is about 24%~81% of the total, and it will increase with high flow velocity and the thin of the pipe. As a result, the friction temperature rising must not be ignored and should be paid enough attention in calculation of the chilled water temperature rising along pipe.

Go to article

Authors and Affiliations

Qi Yudong
Cheng Weimin
Xin Song
Download PDF Download RIS Download Bibtex

Abstract

Vibrational stress relief (VSR) treatment as a method of stress relief is currently performed on different alloys and sizes as an appropriate alternative for thermal stress relief (TSR) method. Although many studies have been performed to extend the knowledge about this process, analytical studies in the field of VSR process seems to require wider efforts to introduce the concept more clearly and extensively. In this study, a theoretical model is proposed based on an analytical equation. The proposed equation was modified in terms of required variables including frequency, amplitude, and vibration duration to encompass more practical parameters compared to the previous models. Thus, essential VSR parameters including the number of cycles as a representative of treatment duration, strain rate as a representative of frequency, and the amplitude were embedded in the model to make it comprehensively practical. Experimental tests were also performed and residual stress distribution was measured by X-ray diffractometry (XRD) method for certain points to compare the experimental results with the theoretical output. An acceptable range of conformation was observed between theoretical and experimental results.
Go to article

Bibliography

[1] R. Dawson. Residual stress relief by vibration. Ph.D. Thesis, University of Liverpool, UK, 1975.
[2] R.T. McGoldrick and H.E. Saunders. Experiments in stress-relieving castings and welded structures by vibration. Journal of the American Society of Naval Engineers, 55(4):589–609, 1943.
[3] P. Sędek and M.S. Węglowski. Application of mechanical vibration in the machine building technology. Key Engineering Materials, 504-506:1383–1388, 2012. doi: 10.4028/www.scientific.net/kem.504-506.1383.
[4] I.K. Lokshin. Vibration treatment and dimensional stabilization of castings. Russian Castings Production, 10:454–457, 1965.
[5] H. Moore. A study of residual stresses and size effect and a study of the effect of repeated stresses on residual stresses due to shot peening of two steels. Proceedings of the Society for Experimental Stress Analysis, 2(1):170–177, 1944.
[6] A. Jurcius, A.V Valiulis, O. Černašėjus, K.J. Kurzydlowski, A.Jaskiewicz, and M. Lech-Grega. Influence of vibratory stress relief on residual stresses in weldments and mechanical properties of structural steel joint. Journal of Vibroengineering, 12(1):133–141, 2010.
[7] K. Liao, Y-X. Wu, and J-K. Guo. Application of VSR technique in stress reduction of aluminum alloy thick plate and its limitation. Journal of Vibration and Shock, 31(14):70–73, 2012. (in Chinese).
[8] M.B. Khan and T. Iqbal. Vibratory stress relief in D-406 aerospace alloy. In: TMS Annual Meeting, pages 807–814, San Francisco, CA, USA, 2009.
[9] J-S. Wang, C-C. Hsieh, C-M. Lin, C-W. Kuo, and W. Wu. Texture evolution and residual stress relaxation in a cold-rolled Al-Mg-Si-Cu alloy using vibratory stress relief technique. Metallurgical and Materials Transactions A, 44(2):806–818, 2013. doi: 10.1007/s11661-012-1450-8.
[10] W. He, B.P. Gu, J.Y. Zheng, and R.J. Shen. Research on high-frequency vibratory stress relief of small Cr12MoV quenched specimens. Applied Mechanics and Materials, 157-158:1157–1161, 2012. doi: 10.4028/www.scientific.net/AMM.157-158.1157.
[11] J-S. Wang, C-W. Kuo, C-C. Hsieh, H-C. Liao, and W. Wu. The effects of waveform in residual stress relief by vibration technique. In: Trends in Welding Research 2012: Proceedings of the 9th International Conference, pages 427-431, Chicago, IL, USA, 4–8 June, 2012.
[12] C. Lin, S. Wu, S. Lü, P. An, and L. Wan. Effects of ultrasonic vibration and manganese on microstructure and mechanical properties of hypereutectic Al–Si alloys with 2% Fe. Intermetallics, 32:176-183, 2013. doi: 10.1016/j.intermet.2012.09.001.
[13] T. Jia, Z. Zhang, C. Tang, and Y. Zhang. Numerical simulation of stress-relief effects of protective layer extraction. Archives of Mining Sciences, 58(2):521–540, 2013. doi: 10.2478/amsc-2013-0035.
[14] Y. Yang. Understanding of vibration stress relief with computation modeling. Journal of Materials Engineering and Performance, 18(7):856–86, 2009. doi: 10.1007/s11665-008-9310-9.
[15] S. Kwofie. Plasticity model for simulation, description and evaluation of vibratory stress relief. Materials Science and Engineering: A, 516(1-2):154–161, 2009. doi: 10.1016/j.msea.2009.03.014.
[16] S. Aoki, T. Nishimura, T. Hiroi, and S. Hirai. Reduction method for residual stress of welded joint using harmonic vibrational load. Nuclear Engineering and Design, 237(2):206–212. 2007. doi: 10.1016/j.nucengdes.2006.06.004.
[17] D. Rao, D. Wang, L. Chen, and C. Ni. The effectiveness evaluation of 314L stainless steel vibratory stress relief by dynamic stress. International Journal of Fatigue, 29(1):192–196, 2007. doi: 10.1016/j.ijfatigue.2006.02.047.
[18] H. Wang and Z. Wang. The embedded VSR system design based on ARM and frequency spectrum analysis. In: 2008 IEEE Pacific-Asia Workshop on Computational Intelligence and Industrial Application, pages 488–492, Wuhan, China, 19-20 Dec., 2008. doi: 10.1109/PACIIA.2008.81.
[19] M.J. Vardanjani, M. Ghayour, and R.M. Homami. Analysis of the vibrational stress relief for reducing the residual stresses caused by machining. Experimental Techniques, 40(2):705–713, 2016. doi: 10.1007/s40799-016-0071-3.
[20] M.J. Vardanjani, A. Araee, J. Senkara, J. Jakubowski, and J. Godek. Metallurgical effects of shunting current on resistance spot-welded joints of AA2219 sheets. Journal of Materials Engineering and Performance, 25(8):3506–3517, 2016. doi: 10.1007/s11665-016-2168-3.
[21] M.J. Vardanjani, A. Araee, J. Senkara, M. Sohrabian, and R. Zarandooz. Influence of shunting current on the metallurgical and mechanical behaviour of resistance spot-welded joints in AA2219 joints. Strojniški vestnik – Journal of Mechanical Engineering, 62(11):625–635, 2016. doi: 10.5545/sv-jme.2016.3682.
[22] B. Kılıç and Ö. Özdemir. Vibration and stability analyses of functionally graded beams. Archive of Mechanical Engineering, 68(1):93–113, 2021. doi: 10.24425/ame.2021.137043.
[23] P. Vergeer. Vibration isolation of dimple plate heat exchangers. M.Sc. Thesis. North-West University, Potchefstroom Campus, North-West University, South Africa, 2013.
[24] S. Li, Y. Kang, G. Zhu, and S. Kuang. Effects of strain rates on mechanical properties and fracture mechanism of DP780 dual phase steel. Journal of Materials Engineering and Performance, 24(6):2426–2434, 2015. doi: 10.1007/s11665-015-1495-0.
[25] A. Grudz. Reducing welding stresses in plates by vibration. Automatic Welding USSR, 25(7):70–71, 1972.
[26] A.S.M.Y. Munsi, A.J. Waddell, and C.A. Walker. Modification of welding stresses by flexural vibration during welding. Science and Technology of Welding and Joining, 6(3):133–138, 2001. doi: 10.1179/136217101101538668.
Go to article

Authors and Affiliations

Mehdi Jafari Vardanjani
1
Jacek Senkara
2
ORCID: ORCID

  1. Department of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran.
  2. Department of Welding Engineering,Warsaw University of Technology,Warsaw, Poland.
Download PDF Download RIS Download Bibtex

Abstract

To solve the problem of large deformation soft rock roadway with complicated stress condition in Baluba copper mine, the characteristics of roadway deformation and failure modes are analyzed deeply on the basis of geological survey. Combined with the theoretical analysis and numerical simulation, the new reinforcement technology with floor mudsill and grouting anchor cable is proposed. Moreover, the three dimension numerical simulation model is established by the software FLAC-3D, the support parameter is optimized by it. The results show that the optical array pitch of the U-steel shelf arch is 0.8 m, and the optical array pitch of the grouting anchor cable is 2.4 m. At last, the field experiments are done all over the soft rock roadway. Engineering practice shows that the deformation of soft rock roadway in Baluba copper mine is effectively controlled by adopting the new reinforcement technology, which can provide certain references for similar engineering.
Go to article

Authors and Affiliations

Aixiang Wu
Shunman Chen
Yiming Wang
Xun Chen
Download PDF Download RIS Download Bibtex

Abstract

In this work, the instability damage modes of yield state of a steel tube at the tension side of a rectangular steel tube-confined concrete (RCFST) column under eccentric compression were classified into two types based on the coupling effect of slenderness ratio (λ) and eccentricity ratio (γ). The two types include the unilateral compression yield failure mode with a smaller value of γ and tensile and compressive yield failure modes on both column sides with a larger value of γ. Further, the parametric analyses were performed by employing the finite element (FE) method and the analytical analysis to test 16 groups of RCFST columns by varying the γ value with different λ values. It was observed that the results of the analysis for the mechanical properties like the responses of load-strain ( P-ε) and RCFST column instability modes correlated well with the results obtained in the experiments. Furthermore, the proposed theoretical method could be used to investigate the roles of γ as a controller against the instability in RCFST columns when compared with λ.
Go to article

Authors and Affiliations

Zhengran Lu
1
ORCID: ORCID
Chao Guo
1
ORCID: ORCID

  1. School of Civil Engineering, Shenyang Jianzhu University, Shenyang 110168, China
Download PDF Download RIS Download Bibtex

Abstract

The main purpose of the study is to investigate the mechanical properties around an underground gas storage cavern in bedded salt rock. Firstly, considering the characteristics of the salt rock formation in China, the mechanical model was simplified into a hollow cylinder, which containing non-salt interlayer. In terms of elastic theory, Love displacement function was developed, and the elastic general solution of stress and deformation components were obtained after determining the undetermined coefficients. Under the same condition, numerical simulation was carried out. The validity of the elastic general solution is verified by comparing to numerical simulation results. Furthermore, Based on the feasible general elastic solution, viscoelastic solution was obtained through Laplace transformation and inverse Laplace transform, which could provide reference for the study on the stability and tightness of underground gas storage carven during operation to some extent.

Go to article

Authors and Affiliations

P. Xie
H.J. Wen
G.J. Wang
J. Hu
Download PDF Download RIS Download Bibtex

Abstract

The paper is dedicated to the robustness analysis of scalar multi-agent dynamical systems. The open problem we aim to address is the one related to the impact of additive disturbances. Set-theoretic methods are used to achieve the main results in terms of positive invariance and admissible bounds on the disturbances.
Go to article

Authors and Affiliations

Katarzyna Topolewicz
1
Sorin Olaru
2
Ewa Girejko
1
ORCID: ORCID
Carlos E.T. Dórea
3

  1. Faculty of Computer Science, Bialystok University of Technology, Poland
  2. Laboratory of Signals and Systems Centrale-Supelec, University Paris-Saclay, France
  3. Department of Computer Engineering and Automation, Universidade Federal do Rio Grande do Norte, UFRN-CT-DCA, 59078-900 Natal, RN, Brazil

This page uses 'cookies'. Learn more