STUDY OF PENDULUM-TYPE VISCOELASTIC SPECTROSCOPY FOR SOLIDS AND FLUIDS

Abstract

Pendulum-type viscoelastic spectroscopy (PVS) and liquid pendulum-type viscoelastic spectroscopy(LPVS) are developed to measure the viscoelasticity of solids and fluids respectively in a frequency sweep at various temperatures Both experimental methods utilize magnetic interactionto general mechanical vibrations of a cantilever beam and its deformation is recordedthrough a laser-based displacement measurement system The magnetic interaction between apermanent magnet and Helmholtz coil can achieve high-frequency driving torque or pure bending moment For PVS the cantilever beam is the specimen under testing For LPVS the cantilever beam is made of a known material and interactions between the beam and its surrounding liquid give rise to its rheological properties In addition to rheological properties LPVS is also capable of determining the size of nanoparticles in colloidal suspension Experiments at elevated temperature for LPVS were achieved by wrapping a heating tape around the container that holds the liquid sample In this work several new designs of LPVS core components were attempted and their performances were analyzed In addition several samples were studied Fresh and hardened cement paste were experimentally studied by LPVS and PVS respectively A class of glue at its liquid state and hardened state was also investigated Furthermore PVS was adopted to study the viscoelastic properties of corrugated cardboard and tire rubber For the corrugated cardboard it was obtained that at 100 Hz dynamic Young’s modulus jE_j = 600 MPa in cross direction and jE_j = 210 MPa in machine direction And dynamic shear modulus jG_j are 100 and 50 MPa Furthermore the cardboard showed tan _ about 0 048 in bending mode and 0 042 in torsion mode For the tire rubber its damping was measured about 0 1 around 100 Hz LPVS was utilized to study the rheological properties of nanoparticle colloidal suspensions glue and a kind of shower gel For glue specimen at its liquid phase we measure the value of tan _ decreases from about 103 at 0 01 Hz to 1 at 100 Hz For hardened glue its loss tangent is about 0 5 to 0 05 between 0 01 and 100 Hz In addition a machine deep learning method is proposed to analyze the particle size and its distribution in colloidal suspensions

Date of Award	2019
Original language	English
Supervisor	Yun-Che Wang (Supervisor)