Stress-strain state of friction joints with laser treatment of contact surfaces

Introduction. Researched is conducted to determine the possibility of using an alternative method - laser cleaning. Laser systems have proven themselves in many areas and are a high-tech and effective solution for many construction problems. Despite this nowadays sandblasting is the most common method of processing contact surfaces of high-strength bolted joints - an outdated technology, with high equipment wear and even dangerous to people’s health. Materials and methods. Sandblast and laser-treated specimens were tested for shear. Before testing, the roughness of the contact surfaces and the tension force of high-strength bolts were tested. During the test, the readings of the meter and dial-indicator were taken. The experiments were carried out on a hydraulic press IPS-500, the samples were provided in a processed form. Results. According to the data obtained, strain graphs were plotted and the shear forces of the samples were calculated. Calculated efforts were compared with standard values. The results show the compliance of samples with the requirements of SP 35.13330.2016 “Bridges and pipes” in terms of strength characteristics. Samples with laser surface cleaning have a safety margin value similar to sandblasted samples. Conclusions. Comparison of the strength characteristics proves the possibility of using laser cleaning of the contact surfaces of friction joints. After the transition from outdated technologies, the process of surface preparation can be made economical and environmentally friendly. The obtained values and data can be entered into a number of regulatory documents, including SP 35.13330.2016 “Bridges and pipes” for future research and the widespread application of the method.