Mechanical Behavior Of Encapsulation Of Soft Material Filaments

The encapsulation of slender flexible filament in confined space is a common phenomenon in many fields such as biology,medicine,mathematics,materials,information and so on.In order to make efficient use of space,slender flexible filament such as DNA,chromatin fibers,surgical catheters and coils,wires,etc.form various complex shapes in confined space.The morphologies and mechanical properties of the encapsulation structures are two important problems,which are closely related to the bio-encapsulation structure and the function of flexible devices.At present,most of the previous works focus on the simulations and experiments of metal wires.However,the encapsulation behaviors of flexible filaments made of soft materials are not been addressed.The effects of mechanical properties of soft materials on encapsulation behavior and their corresponding curvature distribution and energy distribution of encapsulation structures are still not be explored.In this thesis,experimental methods are used to investigate the encapsulation behaviors of soft materials filaments.A two-dimensional disc encapsulation device was designed to encapsulate a typical soft material flexible-rubber band.The effects of encapsulation modes,the friction property of material surface and cavity environments on encapsulation behavior were studied.The evolution of encapsulation structures was investigated.The encapsulation lengths,loop numbers and contact numbers were quantitatively obtained.The mechanical parameters such as box counting dimension,encapsulation rate,curvature distribution and energy distribution were calculated.Three-dimensional cylindrical encapsulation devices with different diameters are also designed to carry out encapsulation experiments of rubber bands.The encapsulation structure evolution of rubber band in cylinders with different diameters was studied.The encapsulation lengths and other parameters were quantitatively counted,and the mechanical parameters such as box counting dimension and encapsulation rate were calculated.In addition,based on the structure of rubber band formed in three-dimensional encapsulation device,compression experiments of ordered encapsulation structures and disordered encapsulation structures were carried out.Compression force-displacement curves and force-encapsulation rate curves were obtained.In addition,a comparative experiment was carried out with hard aluminum wire.These results provide inspiration and guide for the design of confined selfassembly system,assembly of flexible polymer chains,flexible electronic encapsulation and densification technology of slender structures.