Corrosion resistance is an important property requirement for marine paint systems used in naval industry such as for ship's topsides and superstructures, which obliges testing the coating performance in order to make a durable selection of the paint systems. This can be achieved by performing laboratory accelerated corrosion tests recommended for C5M corrosivity class (in particular the standard neutral salt spray test ISO 9227 or the cyclic corrosion test ISO 20340‐Annex A) which give results in a rather short delay (up to 6 months) compared to field exposures in marine atmospheres (several years). It is however well known that these tests may not be fully representative of real ship environmental conditions.
The aims of the present study were thus to compare and estimate the correlation of various accelerated corrosion tests including standardized tests (ISO 9227, ISO 20340, ISO 16701) and newly developed test conditions to field exposures on worldwide operating ships (container carrier vessel and oceanographic ship) and on conventional static marine atmospheric sites (C5M). Fifteen different marine paint systems commonly used for offshore and naval application were selected for the study. From the results, the exposure conditions on the container vessel were the most aggressive ones compared to static exposures after 2 years. The best correlation to such field exposure was observed using the cyclic test ISO 16701 with a deviation inferior to 25%, an acceleration factor of 4 and comparable corrosion aspect. If all testing conditions involving NaCl 5 wt% (including ISO 20340) showed a superior acceleration factor (e.g., about 12), a larger deviation (50%) was however found indicating that these tests did not accelerate the corrosion degradation of the paint systems similarly to field exposures. In addition, conditions for an optimization of ISO 20340 annex A test were found.
The use of variable configuration vehicles creates the possibility of direct control of the contact forces between the foot or wheel of a vehicle and the ground. That control is an important element of the coordination of practical walking machines. Control of the contact forces at each wheel is also attractive for wheeled vehicles. For example, the power consumed in driving such a vehicle is quite sensitive to wheel-ground conditions. In conditions of strict power budgets, as in planetary roving vehicles, it becomes attractive to attempt to minimize power consumption by optimizing the wheel-ground contact forces. Unfortunately, control of contact forces in a wheeled vehicle is very complex because of the non-holonomic nature of the system.In this paper we will review the allocation of contact forces in legged systems and examine the attempts that have been made to apply similar principles to the guidance and propulsion of wheeled systems on uneven terrain. The Adaptive Suspension Vehicle (ASV) and Wheeled Actively Articulated Vehicle (WAAV) from the authors' laboratory will be used as examples, and as sources of experimental validation of theoretical and numerical results. The former is a six-legged walking machine with each leg having three actively controlled degrees of freedom relative to the vehicle body. The latter is a six-wheeled variable configuration vehicle with three-axis, actively controlled, spherical articulations between successive axles.
A large scale design space exploration provides invaluable insight into vehicle design tradeoffs. Performing such a search requires designers to: • define appropriate performance criteria by which to judge the vehicles in the design space; • develop vehicle models to calculate the needed criteria; and • determine suitable velocity profiles as well as grade and terrain conditions to feed into the models. This paper presents a methodology for creating and conducting a design space exploration with particular application to heavy duty series hybrid electric-trucks.
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