Tearing a thin sheet by forcing a rigid object through it leads to complex crack morphologies; a single oscillatory crack arises when a tool is driven laterally through a brittle sheet, while two diverging cracks and a series of concertinalike folds forms when a tool is forced laterally through a ductile sheet. On the other hand, forcing an object perpendicularly through the sheet leads to radi...

PURPOSE To determine the success rate of conventional dacryocystorhinostomy (DCR) and endoscopic DCR performed in patients with acute dacryocystitis. METHODS Records of patients with acute dacryocystitis and operated during 2007-2008 were reviewed. Patients who completed a follow-up of 60 months were included in our study. Demographic characteristics, surgery types, success rate, and follow-u...

Material and methods. The study assessed 2 types of chains. The first phase of the study evaluated 1) the tensile strength of the chains; and 2) elongation at the time of tearing in an environment outside of the oral cavity (without exposition). The second phase of the study evaluated 1) permanent deformation after stretching; 2) elongation at the time of tearing; and 3) the tensile strength of...

Current-driven tearing instabilities dominate magnetic relaxation in self-organized high temperature plasmas such as the reversed field pinch (RFP) and spheromak. In the Madison Symmetric Torus (MST) RFP experiments, they are observed in the form of magnetic field, flow velocity, and current density fluctuations that follow a temporally cyclic sawtooth behavior. During a sawtooth crash, a surge...

This paper was to verify the STAGS (general shell, geometric and material nonlinear) code and the critical crack-tip-opening angle (CTOA) fracture criterion for predicting stable tearing in cracked panels that fail with severe out-of-plane buckling. Materials considered ranged from brittle to ductile behavior. Test data used in this study are reported elsewhere. The STAGS code was used to model...

The physical rules governing the tearing of a packaging or piece paper are not completely elucidated despite being common phenomena in daily life. Here, we investigate how presence straight rigid object, ruler, guides fracture thin sheet within wide range pulling directions. In case isotropic brittle sheets, simple geometrical analysis shows that follows direction vector, which differs signific...

Finite Element Tearing and Interconnecting (FETI) methods are a powerful approach to designing solvers for large-scale problems in computational mechanics. The numerical simulation problem is subdivided into a number of independent sub-problems, which are then coupled in appropriate ways. NURBS- (Non-Uniform Rational B-spline) based isogeometric analysis (IGA) applied to complex geometries requ...

This work concerns a new criterion for hot-tearing evaluation in castings. Algorithm describing the conduction of computer simulations of phenomena accompanying the casting formation, which performing is the preparation stage for using of this criterion, is also described. According to the low recurrence of phenomena occurring during solidification (e.g. grained structure parameters, stresses d...