scholarly journals STUDY ON STRUCTURAL BEHAVIOR OF FRICTION TYPE HIGH STRENGTH BOLTED JOINTS HAVING GAP IN THE CONTACT PLANE

2011 ◽  
Vol 76 (660) ◽  
pp. 417-426
Author(s):  
Hiroyuki SATOU ◽  
Atsuhide HASHIMOTO
Keyword(s):  
High Strength ◽  
Bolted Joints ◽  
Structural Behavior ◽  
Contact Plane

Closure to “Surface Treatment of High-Strength Bolted Joints”

1969 ◽  
Vol 95 (8) ◽  
pp. 1768-1769
Author(s):  
Conrad P. Heins ◽  
Charles T. G. Looney
Keyword(s):  
Surface Treatment ◽  
High Strength ◽  
Bolted Joints

Exploration of novel faying surface treatment for high-strength frictional bolted joints to enhance its after-slip performance

2021 ◽  
Author(s):  
Hitoshi Moriyama ◽  
Ryo Sakura ◽  
Takashi Yamaguchi ◽  
Takai Toshikazu ◽  
Yuta Yamamoto
Keyword(s):  
Surface Treatment ◽  
Load Transfer ◽  
High Strength ◽  
Bolted Joints ◽  
Deformation Capacity ◽  
Slip Coefficient ◽  
Faying Surface ◽  
Treatment Concepts ◽  
Local Slip

<p>Welded joints is adopted rather than bolted joints for megastructure’s connections because the former can carry large force. However, the former has several problems, such as quality control of welding in situ, which the latter can solve. By contrast, as the load transfer ratio of each bolt becomes uneven proportionally to the number of bolts, local slip around extreme bolts occurs before the whole slip. Extreme bolts to which a large shear force is applied will break before other bolts. For utilizing the strength of all bolts, the problem is solved by improving shear deformation capacity in faying surface with novel surface treatment. Here, the treatment concepts were explored, and the coating’s effectiveness was evaluated through friction tests. The deformation capacity can be twice or more than that of conventional treatment, and the slip coefficient doesn’t depend on contact pressure. These features have the advantage to give stable slip behaviour.</p>

scholarly journals Tribological Properties of Connecting Rod High Strength Screws Improved by Surface Peening Treatments

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 344
Author(s):  
Dario Croccolo ◽  
Massimiliano De Agostinis ◽  
Stefano Fini ◽  
Giorgio Olmi ◽  
Luca Paiardini ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Shot Peening ◽  
Frictional Coefficient ◽  
High Strength ◽  
Bolted Joints ◽  
Deep Rolling ◽  
Connecting Rod ◽  
Multiple Contacts ◽  
Increase Rate ◽  
Dry Conditions

Bolted joints are highly loaded components and serious issues may arise from improper fastening and in particular from too high or too low preload. Friction at the underhead plays an important role, as it significantly affects the achievable preload for fixed and controlled tightening torque. In addition, multiple tightening is usually performed on connecting rod screws, which may be a further source of friction increment. This study investigates the effect of two surface treatments, shot-peening and deep-rolling, on the tribological properties upon bolt fastening. This topic was tackled experimentally and the campaign involved MJ9 X 1 4 g grade 13.9 36 NiCrMo connecting rod screws, in both lubricated and dry conditions. The results, processed by statistical tools, indicate that deep-rolling does not affect friction, whereas shot-peening yields significant benefits. As an effect of the generation of dimples and multiple contacts, it is able to lower (up to 25%) the bearing frictional coefficient in lubricated conditions, also making the friction level independent of the number of re-tightenings. For a dry surface, an even higher friction decrease (up to 30%) is achieved. Without lubrication, the friction coefficient keeps increasing for the incremented number of tightenings, but the increase rate is lowered with respect to the untreated surface.

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