Studies On The Wind-induced Damping Properties Of Metal Roof Panels With Rockwool Cores

Large span roof structures basically use metal roof system, which rockwool sandwich roof panel with standing seam system is widely used. The wind pressure pass through the metal roof panel to the purlins and then pass to the main structure. Because of the weak stiffness and damping properties of the rookwool, the roof panel will inevitably effect the wind-induced response of the main structure. Currently, research on the impact of wind-induced damping of roof panel to the main structure is still blank. Specified the wind-induced damping properties of metal roof panels with rookwool three parts of work were done as follow:(1) Compared with the upper and lower metal panel, rockwool is the major contribution to the roof panel damping properties, Studies of mechanical and damping properties of the rockwool material was done by means of tests. With Germany Zwick/Roell universal testing machine, tensile and compression tests of rockwool material were measured, and got the isotropic elastic modulus, Poisson’s ratio and tensile compressive strength of rockwool material. For measuring the rockwool material loss factor, the vibration beam method was measured. And the loss factor-frequency curve of rock wool material is fitted according to the testing results.(2) Damping properties of rockwool sandwich roof panel with standing seam system was studied. The methods of calculating the loss factor of the composite structures was introduced, and then the modal strain energy method was used to analyse the first200modal loss factor of a0.4m×2m rockwool sandwich metal roof, and the damping properties of the roof panels with different sandwich thickness and roof purlins were done. Based on the calculated roof panels loss factor at each mode, further analysis of the roof panel stiffness and damping properties how to effect its corner reaction force at different frequency harmonic loads was done. The analysis showed that the corner reaction force was enlarged because of the limited stiffness of the roof panel, and the vibration reduction at high-frequency excitation was good because of its’damping property.(3) Studied the roof panels’stiffness and damping effect on the structural dynamic response. A span of16m and simply supported beam structure with rockwool sandwich roof panels example was analysed to study the roof panels’stiffness and damping effect on the structure’s moments of midspan. Finally, applied a artificial wind pressure to the simply supported beam structure, and inspected the difference of midspan moments between the situation of considering roof panels and situation of not considering roof panels. The analysis showed that compared to the conventional calculation method, the response of the main structure was induced after considering the roof panels, It demonstrated that it’s necessary to consider the roof panels in the analysis of wind-induced response of the roof structure.