When a rope quickly transfers from a slack state to a taut state, a snapping action occurs and produces a large tensile force which is known as a snap load. Energy is dissipated during this snap load, and it is proposed to use synthetic fiber ropes as a type of passive earthquake damper in order to take advantage of this phenomenon. This thesis is the second phase of a multi-stage research project whose goal is to investigate and develop what will be known as Snapping-Cable Energy Dissipators (SCEDs). The experimental data that was collected in the Master'­s Thesis of Nicholas Pearson was organized and analyzed as a part of this research in order to evaluate the behavior of the ropes during the snapping action. Additional tests were also conducted for this project under more controlled conditions in order to better understand how the ropes change throughout a sequence of similar snap loadings and also to determine the amount of energy that is dissipated. The data from both projects was then used as input parameters for a mathematical model that was developed to characterize the behavior of the ropes during a snap load. This model will be utilized in subsequent research involving the finite element analysis of the seismic response of structural frames containing SCEDs. / Master of Science

Energy is lost when a rope transfers from a slack state to a taut state. This transfer is called a snap load and can be very violent. It is proposed to use synthetic fiber ropes as a type of passive control device in new or existing structures to mitigate seismic response. Experimental static and snap load (dynamic) tests were conducted on various synthetic fiber ropes. An eleven-foot-tall drop tower was built in the Virginia Tech Structures and Materials Laboratory in order to conduct these tests. Force and acceleration of the drop plate, which slides vertically within the drop tower, were measured with respect to time for all dynamic tests. Acceleration data was integrated using the trapezoidal or midpoint rule to obtain velocity and displacement values. Plots were made for each test in order to give a better representation of the results. These plots include representations of force and acceleration vs. time, force vs. absolute displacement, force vs. velocity, and force, acceleration, velocity, and displacement vs. time (during the initial taut phase only). Test results show that energy was dissipated in all of the dynamic drop tests, which was expected. Also, the displacement of each rope did not return to zero at the same time that the force returned to zero after the initial snap load. This proves that the ropes undergo some permanent elongation under load. The stiffness of each rope increased with continuous testing. As more tests are conducted on each rope, the strands are pulled tighter into the braided configuration, which causes the rope to become stiffer. / Master of Science