Finite Element Analysis of Ring-on-Ring Test on LCD Panels

Paper No P41: Predicting Change in Cell Gap in LCD Panels Subjected to Touch Force

“…By comparing these three cases, it can be concluded that spacers and liquid crystal do not influence the global deformation of the panel. This conclusion is in line with references [ , which validate finite element models where spacers and liquid crystal were replaced with frictionless contact with experimental stress. Figure compares change in cell gap for the case where both spacers and liquid crystal were considered in the model with a case where only spacers were considered in the model.…”

Design and development of ring-on-ring jig for biaxial strength testing of brittle ceramic composite materials: ZrB2-30wt-%SiB6

“…Figure 12 shows how the radial, σ r , and tangential, σ t , stresses on the tensile surface vary as a function of the radial distance for the simulation with coefficient of friction of 0.1. σ r and σ t are equal at the centre of the tensile surface of the disk sample in the region enclosed by the load ring represented by the area marked by A-B in Figure 12. Vepakomma et al [10] and Hsueh et al [21] show that in a ring-on-ring simulation, the variation of maximum principal stress along the radial direction of the tensile surface shows a peak that occurs in the region enclosed by the load ring indicating that the stress is no longer uniform. The same behaviour was found in the simulation developed in this paper where, in Figure 12, σ r is larger than σ t for a small region, peaking in the line marked by C , and decreasing rapidly as the radial length distances from the centre of the disk.…”

“…The guidelines for the ring-on-ring fixture design and the sample's dimensions can be found in the standard ASTM C1499, where the relationships between sample's geometry and jig dimensions are presented [5]. Owing to the popularity and versatility of the ring-on-ring test its range of application varies from dental material application, such as ceramic dental restorations [9], to the test of biaxial strength for LCD display panels [10] found in today's televisions and cell phones. The ring-on-ring geometry of the biaxial testing jig was adopted as ISO-6474 for orthopaedic alumina and zirconia ceramics.…”

Strain distribution and electrical characteristics of flexible low-temperature polysilicon thin film transistors under biaxial bending

“…The simulation cloud shows that the maximum tensile biaxial stresses occur within the loading ring. Within the region enclosed by the loading ring, the centres εr and εθ of the tensile surface of the disc specimen are equal [14]. In the on-ring simulations, the maximum principal stresses vary radially along the tensile surface and reach an inflection point in the region enclosed by the loading ring, indicating that the stresses are no longer uniform.…”