Behaviour of a Preloaded Asymmetric Multi-Bolted Connection Under Cyclic Loads by Experimental Research

Area of Science:

• Mechanical Engineering
• Structural Analysis
• Experimental Mechanics

Background:

• Multi-bolted connections are critical in many engineering structures.
• Understanding load distribution and stability in asymmetrical connections is essential for safety and performance.
• Preloading is a common technique to enhance connection integrity.

Purpose of the Study:

• To experimentally investigate the behavior of preloaded asymmetrical multi-bolted connections under cyclic operating conditions.
• To analyze the distribution of forces within the bolts during cyclic loading.
• To validate the stability and performance of such connections.

Main Methods:

• Bolts were preloaded in a specific order using a calibrated strain gauge system.
• Connections were subjected to sinusoidal loads (10 kN and 20 kN) at various frequencies on an Instron 8850 testing machine.
• Data acquisition and processing were performed using MATLAB/Simulink R2018b.

Main Results:

• Bolt forces exhibited cyclic variations relative to initial preload values.
• Due to connection asymmetry, force variations differed among individual bolts.
• Observed bolt force deviations remained within ±2%, indicating stable performance.

Conclusions:

• The asymmetrical multi-bolted connection demonstrated stability under cyclic operating loads.
• Experimental results provide valuable data for validating systemic modeling approaches for bolted connections.
• The findings confirm the effectiveness of preloading in maintaining connection integrity.