A Report on the Experiment of Shearing Bolt Connection

2026-08-06 22:03

The following is a summary and reflection report on the experiment of the shear bolt connection: ** I. Experiment summary ** 1. ** Type and Principle of Shearing Bolt Connection ** - The shear-resistant connection relied on the screw to bear the pressure and the shear-resistant to transmit the external force in the direction of the rod axis. In the experiment, different connection methods and stress conditions could be observed. For example, in the high-strength bolt connection, the friction type high-strength bolt connection was to tighten the high-strength bolt, so that the screw produced a pre-tension to compress the contact surface of the component, and the friction of the contact surface prevented the relative slip to achieve the purpose of force transmission. The damage criterion was the relative slip of the plate. However, the high-strength bolt connection allowed the contact surface to slip, and the failure criterion was that the connection reached its limit state. - For the tension connection, the screw was used to transmit the external force parallel to the rod axis, and the plates had the tendency to separate from each other. The connection of the joint action of tension and shear relied on the screw to transmit both the external force vertical to the rod axis and the external force parallel to the rod axis. 2. ** Destruction Mode ** - In the experimental study, it was observed that there were many failure modes such as shear-out failure, tearing failure, bearing failure, net section failure and bolt shear failure. For example, Q690 high-strength steel showed good local deformationability in the test, but different bolt grades, specifications, pre-tension, bolt arrangement, end distance, and edge distance would affect the appearance of the failure mode. 3. ** Force Phase ** - In terms of the working performance of high-strength bolts, the stress process was similar to that of ordinary bolts. It was divided into four stages: the elastic stage of friction force transmission, the sliding stage, the elastic stage of bolt force transmission, and the elastic and plastic stage. However, due to the large friction between high-strength bolt connections, the first stage was far greater than ordinary bolts. 4. ** The influence of bolt related parameters ** - The grade and specifications of the bolt had an impact on the connection performance. In the experiments, it was found that bolts of different grades and specifications had different performances in transmitting force and resisting damage. - The pretension was also a key factor. For example, in the experiment of large hexagonal high-strength bolts, under-tightening would cause the pre-tension to be less than the value specified in the code, resulting in the friction between the nodes being less than the set value, and the shear bearing capacity could not reach the rated value. Over-tightening may cause the thread to be damaged, the screw to be over-stretched, causing the "necking" phenomenon or even breaking, or crushing the connected parts, and may cause delayed fracture of the bolt, bringing safety risks. - The hole diameter and shape of the high-strength bolt hole, the permitted distance between the hole and the edge, as well as the space requirements for the construction tools to operate when arranging the bolts, will also affect the performance of the shear bolt connection. In the process of the experiment, it is necessary to consider the reasonable setting of these factors. 5. ** Inspection and Quality Control in the Experiment ** - The quality inspection of high-strength bolts was divided into two stages. The first stage of process inspection included the installation method of high-strength bolts, the installation process, the treatment and cleaning of the connecting surface, the tightening sequence and tightening method, etc. This stage directly determined the quality of the connection. - The second stage was the quality inspection after tightening. For large hexagonal high-strength bolts, the small hammer striking method can be used to conduct a general survey to prevent missing tightening. Some bolts can be randomly checked through the moment inspection, and the time requirements for the moment inspection should be paid attention to. The connection of the high-strength torsion-shear bolt could be judged by checking whether the quincunx head was broken. For special cases, it could be tested according to the test method of the big hexagon bolt. At the same time, the integrity of the acceptance data must be ensured during the experiment, such as the quality assurance certificate of high-strength bolts, the anti-slip coefficient test report, etc. ** 2. Reflection ** 1. ** Experiment design ** - When designing experiments, there might be situations where some influencing factors were not considered comprehensively. For example, there was no in-depth study of the changes in the performance of the connection of the anti-shear bolt under different environmental conditions (such as temperature, humidity, etc.). In practical engineering applications, environmental factors may have an important impact on the reliability of the connection. - There may be limitations in the selection and number of experimental samples. When studying the different grades and specifications of bolts, more types and numbers of samples may be needed to draw a more accurate general conclusion. 2. ** Experiment Operation ** - During the experimental operation, although there were relevant standards and methods for the tightening process of the bolt, there might be some errors in the actual operation. For example, when using the corner method or the torque-based method, how to control the pre-tension more precisely to avoid under-tightening or over-tightening situations required further improvement in operating techniques or the use of more precise tools. - In terms of observation and recording of experimental data, there might be some areas that were not detailed enough. For example, when recording the failure mode, the recording and analysis of some transition states or composite failure modes may not be in-depth enough, which may affect the comprehensive and accurate understanding of the connection performance. 3. ** Connection between theory and practical application ** - There was a certain gap between the experimental results and the actual engineering application. The connection performance data under ideal conditions obtained in the experiment may be different in actual engineering due to the complexity of the structure and the difference in construction quality. Therefore, further research was needed on how to better apply the experimental results to practical engineering to ensure the safety and reliability of the steel structure connection. Read more exciting novels for free