scholarly journals Feasibility Study on ECC Fatigue Life Extension through Self-healing

2016 ◽  
Author(s):  
Jishen Qiu ◽  
Pui See Phan ◽  
En-Hua Yang
Keyword(s):  
Fatigue Life ◽  
Feasibility Study ◽  
Life Extension ◽  
Self Healing

scholarly journals Life extension of self-healing polymers with rapidly growing fatigue cracks

2006 ◽  
Vol 4 (13) ◽  
pp. 395-403 ◽  
Author(s):  
A.S Jones ◽  
J.D Rule ◽  
J.S Moore ◽  
N.R Sottos ◽  
S.R White
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Relative Magnitude ◽  
Life Extension ◽  
Self Healing ◽  
Grubbs Catalyst ◽  
Fourfold Increase ◽  
Endurance Limits ◽  
Kinetics Of

Self-healing polymers, based on microencapsulated dicyclopentadiene and Grubbs' catalyst embedded in the polymer matrix, are capable of responding to propagating fatigue cracks by autonomic processes that lead to higher endurance limits and life extension, or even the complete arrest of the crack growth. The amount of fatigue-life extension depends on the relative magnitude of the mechanical kinetics of crack propagation and the chemical kinetics of healing. As the healing kinetics are accelerated, greater fatigue life extension is achieved. The use of wax-protected, recrystallized Grubbs' catalyst leads to a fourfold increase in the rate of polymerization of bulk dicyclopentadiene and extends the fatigue life of a polymer specimen over 30 times longer than a comparable non-healing specimen. The fatigue life of polymers under extremely fast fatigue crack growth can be extended through the incorporation of periodic rest periods, effectively training the self-healing polymeric material to achieve higher endurance limits.

scholarly journals Experimental Investigation of the Performance of a Hybrid Self-Healing System in Porous Asphalt under Fatigue Loadings

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3415
Author(s):  
Shi Xu ◽  
Xueyan Liu ◽  
Amir Tabaković ◽  
Erik Schlangen
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Rest Period ◽  
Life Extension ◽  
Fatigue Properties ◽  
Self Healing ◽  
Porous Asphalt ◽  
Healing Effect ◽  
Healing System ◽  
Healing Efficiency

Self-healing asphalt, which is designed to achieve autonomic damage repair in asphalt pavement, offers a great life-extension prospect and therefore not only reduces pavement maintenance costs but also saves energy and reduces CO2 emissions. The combined asphalt self-healing system, incorporating both encapsulated rejuvenator and induction heating, can heal cracks with melted binder and aged binder rejuvenation, and the synergistic effect of the two technologies shows significant advantages in healing efficiency over the single self-healing method. This study explores the fatigue life extension prospect of the combined healing system in porous asphalt. To this aim, porous asphalt (PA) test specimens with various healing systems were prepared, including: (i) the capsule healing system, (ii) the induction healing system, (iii) the combined healing system and (iv) a reference system (without extrinsic healing). The fatigue properties of the PA samples were characterized by an indirect tensile fatigue test and a four-point bending fatigue test. Additionally, a 24-h rest period was designed to activate the built-in self-healing system(s) in the PA. Finally, a damaging and healing programme was employed to evaluate the fatigue damage healing efficiency of these systems. The results indicate that all these self-healing systems can extend the fatigue life of porous asphalt, while in the combined healing system, the gradual healing effect of the released rejuvenator from the capsules may contribute to a better induction healing effect in the damaging and healing cycles.

Comparative assessment of rubber steel cables for vertical mine hoists

2020 ◽  
pp. 85-93
Author(s):  
V. E. Perekutnev ◽  
V. V. Zotov
Keyword(s):  
Feasibility Study ◽  
Carrying Capacity ◽  
Load Distribution ◽  
Comparative Assessment ◽  
Life Extension ◽  
Steel Cable ◽  
Motion Stability ◽  
Cable Length ◽  
Steel Cables ◽  
Mine Hoist

Operation of inhaul rubber steel cables in vertical mine hoisting is discussed. The research in the field of mine hoisting is reviewed, and the further R&D directions are identified. Some studies concern life extension of hoisting ropes. One of the promising trends seems to be application of belt pullers as inhaul cables, which can essentially enhance mine hoist efficiency. In the meanwhile, capabilities of rubber steel cables suffer from deficient attention. The performance capabilities of rubber steel cables of top manufacturers (Promkanat and SAG) are compared, and application ranges in vertical mine hoisting are determined for such cables. It is found that the Polish manufacturer’s rubber steel cables offer a wider range of application. The analysis shows that rubber steel cables can be used as inhaul cables of vertical mine hoisters. Rubber steel cables possess suitable characteristics and are capable to elevate considerable loads to various hoisting heights. In particular, the existing rubber steel cables ensure carrying capacity of hoists up to 20-25 t at the hoisting heights to 400-500 m and sometimes can elevate skips with tonnage of 10 t to a height up to 1000 m and more. The further feasibility study of operation of inhaul steel rubber cables in hoisting units should address motion stability of a puller on a driving drum, load distribution in ropes of base of rubber steel cables, validation of hoister design, adjustability of rubber steel cable length during its operation, etc.

scholarly journals Correction: Wang et al. Generalized SCF Formula of Out-Of-Plane Gusset Welded Joints and Assessment of Fatigue Life Extension by Additional Weld. Materials 2021, 14, 1249

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2331
Author(s):  
Yixun Wang ◽  
Yuxiao Luo ◽  
Yuki Kotani ◽  
Seiichiro Tsutsumi
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Life Extension ◽  
Out Of Plane

The authors wish to revise in the text of Appendix A, pages 19–21 [...]

scholarly journals Generalized SCF Formula of Out-Of-Plane Gusset Welded Joints and Assessment of Fatigue Life Extension by Additional Weld

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1249
Author(s):  
Yixun Wang ◽  
Yuxiao Luo ◽  
Yuki Kotani ◽  
Seiichiro Tsutsumi
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Welded Joints ◽  
Life Extension ◽  
Leg Length ◽  
Notch Stress ◽  
Out Of Plane ◽  
Weld Toe ◽  
Effective Notch Stress ◽  
Geometric Effects

The existing S-N curves by effective notch stress to assess the fatigue life of gusset welded joints can result in reduced accuracy due to the oversimplification of bead geometries. The present work proposes the parametric formulae of stress concentration factor (SCF) for as-welded gusset joints based on the spline model, by which the effective notch stress can be accurately calculated for fatigue resistance assessment. The spline model is also modified to make it applicable to the additional weld. The fatigue resistance of as-welded and additional-welded specimens is assessed considering the geometric effects and weld profiles. The results show that the error of SCFs by the proposed formulae is proven to be smaller than 5%. The additional weld can increase the fatigue life by as great as 9.4 times, mainly because the increasing weld toe radius and weld leg length lead to the smaller SCF. The proposed series of S-N curves, considering different SCFs, can be used to assess the welded joints with various geometric parameters and weld profiles.

Fatigue Life Extension of Riveted Connections

1975 ◽  
Vol 101 (12) ◽  
pp. 2591-2608 ◽  
Author(s):  
Harold S. Reemsnyder
Keyword(s):  
Fatigue Life ◽  
Life Extension
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