Finite element modeling of static tire enveloping characteristics

To investigate static tire enveloping characteristics, a three dimensional (3-D) finite element model is proposed. The vertical stiffness of the tire is studied on a flat surface with and without cleat. Tire rubber materials and cord layers are represented independently using "rebar" elements available in MSC Marc Mentat. Comparisons of numerical and experimental results are given to show the validity of the proposed model. It is shown that after a certain displacement, the results of the proposed model agree well with experimental results. In addition, the model results show that regardless of the type of the cleat placed under the rim center (hub center), all vertical force curves intersect after a certain displacement, which indicates typical static enveloping characteristics. Moreover, another typical characteristic of the radial tires that is unlike those of bias-ply constructions confirms that the contact patch does not expand laterally after a level vertical load is applied to the tire, which is directly related to fuel consumption and tire tread life

Cost-Effectiveness of Dual Antimicrobial Therapy for Gonococcal Infections Among Men Who Have Sex With Men in the Netherlands

Transplantation and autoimmunit

Experimental and Numerical Investigation of the Flow Topology During Airdrop Operations

This paper reviews experimental and numerical simulations of the dropping of simplified cargo supplies from a generic military transport aircraft carried out at DLR. Aiming at developing a well-validated process chain to accurately compute the trajectories and attitudes of airdropped cargo supplies in the proximate vicinity of the aircraft, extensive low-speed wind tunnel tests were conducted as a means to validate the numerical simu- lation. A simulation environment was established, coupling unsteady Navier-Stokes CFD methods with multi-body simulation methods, allowing for the precise computation of the time-dependent aerodynamic and ight mechanic behaviour of an airdropped supply. A comparison of selected results between the numerically simulated airdrop and the wind tunnel data is presented