The purpose of this study was to evaluate the effects of screwdriver handle shape, surface material and workpiece orientation on torque performance, finger force distribution and muscle activity in a maximum screwdriving torque task. Twelve male subjects performed maximum screw-tightening exertions using screwdriver handles with three longitudinal shapes (circular, hexagonal and triangular), fo...

Bolted joints are generally used to connect two or more mechanical structures due their ease of assembly and disassembly for maintenance. However, the problem vibration is one main challenges when tightness bolted insufficient, causing failures such as looseness resulting in disconnection. Looseness most common cause dynamically loaded joint structure failure. This study tested a simple bolt ob...

This study measured the screw joint preload of the implant-abutment interface for 7 common hex-top abutment systems. Increasingly, prosthetic designs are utilizing a direct prosthetic connection to the implant, placing the implant-abutment screw joint under direct functional loads and moments. Sufficiently high screw joint preloads are required to maintain screw joint integrity and confer clini...

A preliminary study of acoustic emission during orthopaedic screw fixation was performed using polyurethane foam as the bone-simulating material. Three sets of screws, a dynamic hip screw, a small fragment screw and a large fragment screw, were investigated, monitoring acoustic-emission activity during the screw tightening. In some specimens, screws were deliberately overtightened in order to i...

The aim of this study was to verify whether screw abutment lubrication can generate higher preload values compared to non-lubricated screws, a titanium abutment was screwed onto an implant analog and scanned with the Procera System to generate 20 zirconia abutments. MKIII Brånemark implants were clamped to a precision torque device, and the abutments were distributed in dry and wet groups with ...

Bolt tightening torque has an influence on the fatigue life of multi-bolted joints which cannot be ignored, but there are few methods to predict composite structure by considering bolt torque. A prediction method is proposed. It can take into account various damages bolts and laminates accurately calculate damage evolution structure. The being composed T300/BMP-316 TC4 titanium alloy used verif...