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Hand and power tools
Published in Andrew Livesey, Alan Robinson, The Repair of Vehicle Bodies, 2018
A wide range of special chisel bits is produced for the power tool. Most of these are cutting chisels of various sizes, used for general dismantling, cutting rivets, nuts, bolts and the removal of spot-welded sections. There is also a special thin-gauge metal cutting chisel for use on panel work, and a recessing tool which can be fitted on the end of the chisel. The recessing tool can be used on the edges of panels to form a lip or joggled section so that one panel passes over the face of the other, forming a flush finish which is ideal for spot-weld connections and joints in panels.
Flexural strengthening of large-scale damaged reinforced concrete bridge slab using UHPC layer with different interface techniques
Published in Structure and Infrastructure Engineering, 2022
Yanping Zhu, Yang Zhang, Husam H. Hussein, Minghong Qiu, Dongliang Meng, Genda Chen
In reference (Zhang, Li, Zhu, & Shao, 2020), the damaged RC beams were strengthened by toughness-improved UHPC at the tension side. The pre-damage degrees were evaluated by preloaded maximum crack widths of 0.2 mm, 0.3 mm, and 0.4 mm. The surface of the RC substrate was roughened and saturated before strengthening. Hor, Teo, and Kazutaka (2017) conducted a rehabilitation series for repairing deteriorated RC structures and an overlying series for retrofitting soffits of RC members on rectangular RC slab specimens. The top surface of the RC substrate was roughened randomly by chisel and hammer to obtain a good bonding surface. Results showed that cracked UHPC exhibited strain-hardening behavior, and the ductility of the strengthened slab was significantly improved. In references (Zhang et al., 2019) (Zhu, Zhang, Hussein, & Chen, 2020), several pre-damaged RC slabs were strengthened by the UHPC layer, and the flexural behaviors were experimentally and numerically studied. The interface treatment included a combination of roughening and planting steel studs. Tanarslan (2017) and Tanarslan, Alver, Jahangiri, Yalçınkaya, and Yazıcı (2017) studied the flexural behavior of RC beams strengthened with prefabricated UHPC laminates with and without steel bars. The effect of two types of interfacial connections between the UHPC layer and the RC beam, epoxy resin, and mechanical anchorage on the flexural capacity was investigated. Results showed that the carrying load capacity of the specimen with mechanical anchorage was improved. Also, the reinforcement efficiency of the UHPC layer with steel bars was higher than that without steel bars.
A review on strengthening, delamination formation and suppression techniques during drilling of CFRP composites
Published in Cogent Engineering, 2021
Dhruv Rathod, Mihir Rathod, Ronak Patel, S.M. Shahabaz, S. Divakara Shetty, Nagaraja Shetty
The stress-induced between the layers transcends to the bond strength between the layers. The chisel edge of the tool applies an abrasive force on the plies at this stage. As the process further progresses, the chips exit the laminate along the slope of the flute. Thus, a vertical pulling force is applied axially upwards due to the cutting action, which separates the top plies of the composite. In contrast, the tool applies a thrust force in the opposite direction on the intact layers at the bottom. Delamination is caused due to the force induced by the cutting motion at the boundary of the hole. Hence, delamination mainly depends on thrust force and distribution of force on the cutting edges and the interlaminar strength.
Experimental characterization and finite element modeling of critical thrust force in cfrp drilling
Published in Machining Science and Technology, 2018
Kamlesh Phapale, Ashwin Ahire, Ramesh Singh
The prediction error is within the experimental scatter. The minor errors can be attributed to the assumption made in numerical modeling. The geometric simplification of tool, as the twist drill flutes and point angle at chisel edge are excluded from geometric construction of drill bit. Also simplified boundary conditions may have some effect on drilling-induced forces. It can be clearly seen that an indentation-based model can capture the exit delamination with reasonable accuracy.