Slotted Beam-Column Energy Dissipating Connections: Applicability and Seismic Behavior

Energy dissipating joint can effectively strengthen the connection of prefabricated buildings. In the present study, a new slotted mild steel damper was installed at the beam end of the prefabricated structure to form as the energy-dissipating joint of the beam-column. By using ABAQUS software, a finite element (FE) analysis was conducted for the single-story-and-span of the single-frame structure with a slotted damper as energy-dissipating joint. The result shows that the damper was the first to yield in the structure and performed well in energy dissipation, indicating its reasonable design of structure and connection. The energy dissipation mainly occurred at the flange of the variable cross sections, between which beam-ribbed webs ensured the required bearing capacity and stiffness and provided a reliable connection. The hysteretic curves were obtained by analyzing the mechanical properties of the slotted damper under pure bending and pure shearing. In the OpenSees platform, the Steel02 Material model and the twoNodeLink element were used to fit the hysteretic curves; this method was employed for the parametric simulation of the slotted energy dissipation. The dynamic characteristics and seismic response of the controlled structure with slotted energy dissipating joint were also analyzed and compared with those of the uncontrolled structure in the OpenSees platform. The results show that the period of the controlled structure was prolonged and the top story acceleration decreased, indicating its effect in reducing seismic response. The shear-dependent seismic reduction ratio was about 35%, while the drift-dependent seismic reduction ratio was about 10%. The seismic performance of bottom story was better than that of the top story, and the damper has good energy dissipation performance in the bending direction. Some detailed design criteria are put forward and consequences for design on the basis of the performed simulations are shown.

Evaluation of the Composite Barrier Natural Oscillations Influence on the Generated Shock Loading

The problem of studying behavior of various structures under the influence of intense impulsive (shock) loads arising during operation of many modern facilities, machines and devices remains relevant for many years. Shock loading in laboratory conditions is generated due to interaction between the test object and the braking device (barrier). In this case, braking device or barrier could be a one-piece or a prefabricated structure. If the braking device (barrier) dimensions commensurate with the test object, the braking device natural oscillation frequencies excited during interaction between the test object and the braking device (barrier) could be found in the range of the test object natural oscillation frequencies. Frequency determination within the signal spectrum registered on the test object and caused by oscillations of the braking device (barrier) or test equipment, would assist in better assessing the test object shock loading and its compliance with real operating conditions

Study on Prefabricated Firewall with Truss Load

In this paper, a prefabricated structure is used to study the main transformer firewall with truss structure of the substation. The beams, columns and wall panels of the firewall are prefabricated components, and the cast-in-place structure is used only at the top beam and column joints.

АНАЛІЗ КОНСТРУКТИВНИХ ОСОБЛИВОСТЕЙ З'ЄДНАНЬ СИЛОВИХ ЕЛЕМЕНТІВ КРИЛА ЛІТАКІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

Ensuring the fatigue life of the aircraft structure is a requirement for flight safety, and for a cost-effective aircraft. A plane with a long lifetime can perform more flights, reduce routine maintenance costs and increase airline profits. Market trends in the aviation industry show the interest of airlines in long life aircraft. Structural elements of the wing are joined by fasteners. The wing structure fatigue is determined by the endurance of regular zones. Regular zones include longitudinal, transverse joints. The fatigue life of the wing irregular zones should be no less than the fatigue life of the regular zone. The article provides an analysis of the design features of the wing structural element joints performing short and medium flights, ANTONOV and Boeing, which have reached a high level in this field of research. Structural schemes of the wings, location and execution of the joints of the wing structural parts using facilities that improve take-off and landing characteristics (such as ailerons, flaps, slats and spoilers) are analyzed. The types, diameters and materials of fasteners that vary within the wing limits are considered. Attention was focused on such important indicators as the edge tolerance, distance between the fasteners (spacing), wing and fastener construction materials. The wing is made of a prefabricated structure, to ensure safety requirements for permissible destruction. In turn, this leads to an increase in the amount of fasteners. Since fatigue life is affected not only by the kinds of materials, parameters of fasteners, rated stresses, but also the degree of load transferring between parts. The constructive execution of the longitudinal and transverse connections of the load-bearing elements was analyzed to further study the degree of load transfer in a difficult - stressed state. The materials of the article provide an opportunity for further in-depth research on the general and local stress-strain state of the wing.