دانلود رایگان مقاله انگلیسی مطالعه تجربی و عددی بر رفتار مکانیکی اتصالات فولادی با مقاومت بالا Q460D - الزویر 2018

abstract

Based on static tensile test of 20 Q460D high-strength steel bolted connection joints, influences of high-strength steel material strength and bolt arrangement pattern on bearing capacity and deformation of connections were analyzed. According to differences of end distance, edge distance, and pitch between bolts, finite element modeling, theoretical calculation, and test results were compared, a quantitative analysis was carried out for mechanical property of high-strength steel bolted connections, and applicability of relevant standards was investigated. The study showed that bearing capacity and deformation of specimens for Q460D high-strength steel increased as pitch increased when bolts were under transversal arrangement. Influence of increased edge and end distance on bearing capacity of the connection was minimal after standard value of the structure was reached. Stress nephogram obtained from numerical analysis and plastic region presented symmetrical distribution with two holes bearing balanced stress, fitted curve points were dispersedly distributed, and margin of theoretically calculated value was large when EC3 standard was used. When bolts were under longitudinal arrangement, bearing capacity of the specimens only presented a linearly increasing trend as pitch increased, two holes bore unbalanced stress in stress distribution, stress borne by bolt hole at end part and its deformation were both large, and bearing capacities of end and middle bolts calculated according to the EC3 standard were relatively accurate. This study can provide a theoretical basis for design and connection structure of Q460D high-strength steel bolted connection joints.

Conclusions

Influences of parameters, such as bolt arrangement pattern and joint construction on mechanical properties of connection joints, were discussed based on an experimental study of the properties of Q460D high-strength steel bolted connections. The following conclusions could be obtained:

1) Failure mode and bearing capacity of bolted connection joints were closely related to bolt arrangement pattern and structural form. An equation was established according to force equilibrium and deformation coordinating conditions. The difference value between initialslippage load obtained through theoretical computation and test value did not reach 4% with favorable applicability.

2) When bolts were under transverse arrangement, specimen bearing capacity presented a linear growth with end distance, edge distance, and bolt pitch; fitting trend through ANSI standard was quite approximate while the EC3 standard was partially conservative. When bolts were under longitudinal arrangement, net crosssection capacity of the connection only presented a linear growth trend as edge distance increased, influence ranges of end distance and bolt pitch did not exceed 3%, and the EC3 standard had improved fitting effect.

3) Finite element model coincided with test results very well in reflecting specimen stress distribution, failure mode, and bearing capacity. When displacement value was d0/6, bearing capacity could reach over 85% of ultimate bearing capacity, and difference value between test value and numerical analysis result was within 10%.

4) When bolts were under transverse arrangement, two bolt holes bore relatively uniform stresses, and stress nephogram and plastic region were under symmetrical distribution; when bolts were under longitudinal arrangement, two holes bore non-uniform stresses, and end bolt holes bore large stress and experienced large deformation.

5) For Q460D steel, the deviation was large when the EC3 standard formula was used to compute bearing capacities of bolts under transverse arrangement; for bolt specimens under longitudinal arrangement, computational effects of end bolts and inner bolts were satisfactory.