Papers by Keyword: Normal

Abstract: Based on the discrete element numerical simulation, the change of failure modes of slope influenced by parameters of rock mass structural plane is studied. It is shown the failure modes shift gradually from the bedding sliding failure modes to the sliding-bending failure modes with the increase of the strength of the rock mass structural plane; The slope failure modes are mainly sliding failure modes with the increasing of the normal and shear stiffness and spacing of rock structural plane. Failure modes shift from shearing slip failure modes to shearing slip and buckling failure modes and finally to the tilting failure modes with the increase of the rock structural plane dip angle. The impact of the rock structural plane cohesion to the slope stability is the greatest, and the stiffness is the least.

Abstract: Soil adheres to the surfaces of soil engaging components of earthmoving machinery and equipment. It has been pbserved that up to 50% of energy may be consumed in overcoming adhesion and friction of soil to the surfaces of soil engaging components of agricultural and earthmoving machinery. Surface morphology, chemical composition, elasticity, lubrication mechanism and electric osmosis play significant roles in reducing adhesion, friction and energy consumption of various equipment. Some of these techniques have very limited application in the practical field conditions because of the time and amount of fluid required to achieve the desired results. Whereas other techniques are effective in reducing adhesion and friction and improving work quality of these machines and equipment. This paper analyses the forces including the drafts of conventional and bionic bulldozing blades operating under identical conditions using mathematical modelling. The force analysis showed that both adhesion and friction play major role in reducing drafts of earrthmoving machinery. It is also worth stating that both the surface morphology and the construction materials play important role in reducing adhesion and friction of ground eganging components of earthmoving machinery.

Abstract: The effects of varying distribution type of random variables and environmental, operational, and design random variables influenced by a shock wave caused from various origins on the failure probability are systematically investigated using the first order reliability method (FORM) for buried pipeline. It is found that the failure probability of the buried pipeline increases with faster P-wave velocity and slower S-wave velocity. The failure probability is estimated to be the largest for the Weibull distribution and the smallest for the lognormal distribution. A set of similar values of the failure probability for the normal distribution and lognormal distribution are noted. The normalized margin is defined and estimated. Furthermore, the normalized margin is used to predict the failure probability simply by using the fitting lines between the failure probability and the normalized margin.

Abstract: Grinding and polishing are widely used for glass machining with fine finished surfaces. These processes result from abrasion due to repeated contacts between hard sliding particles and the glass surface. The study of contact mechanics problem is of fundamental interest to understand the process of material removal in glasses. In order to get insight into this problem, an experimental set up was designed which allows a monotonic loading of the indenter combined with a controlled sliding of the specimen to simulate a slow abrasive machining process. In addition, the experiments are conducted with an in-situ video monitoring that allows for the observation of the different fracture phenomena beneath the indenter. Fracture surfaces were also studied using SEM and AFM for multi-scale investigation. Fracture analysis was carried on a standard float glass, four different SLS glasses and a fused silica glass. The observed phenomena were discussed in the light of the influence of the normal load and the chemical composition.