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IMO Grain Regulations require a minimum level of acceptable stability for grain transportation, represented by the roll angle due to the conditional grain displacement, the residual restoring energy after such an assumed grain displacement and the initial metacentric height. Modern loading complexes for transshipment of grain crops are highly productive, which requires constant monitoring of the ship's position, including adjusting the length and tension of the mooring ropes. Along with mooring winches, windlass and capstan, dynamic mooring cleats are also involved in this process. The analysis of the mooring devices showed that the most effective for correcting the position of the vessel is the use of controlled bollards in combination with automatic winches. However, the experience of using the controlled bollards of known designs indicates that their designs contain solutions that significantly limit the possibilities of use in the rapidly changing position of the vessel or in difficult climatic conditions. The proposed design differs in that the pedestals have electromechanical stoppers with force sensors, the fingers are installed on the axes of rotation of the pedestals and are connected to the shafts of piezoelectric motors, which are rigidly attached to the base, and together with the stopper are connected to the control unit. Thus, the developed device will provide: expansion of the range of operating modes for the use of mooring bollards due to the use of piezoelectric motors; simplification of the design; no need to compensate for the influence of climatic factors on the bollard elements; no threat of environmental pollution by hydrocarbon working substances; improving maintainability due to the choice of a modular design. The use of the developed device will make it possible to quickly maintain a safe position of the ship during cargo operations. Thus, the developed device will provide: - expansion of the range of operating modes for the use of mooring bollards due to the use of piezoelectric motors; - simplification of design implementation; - no need to compensate for the influence of climatic factors on the bollard elements; - no threat of environmental pollution by hydrocarbon working substances; - increase in maintainability due to the choice of modular design and availability for technical diagnostics. The use of the developed device will allow to promptly maintain safety by the position of the vessel during cargo operations. [ABSTRACT FROM AUTHOR]

An actual test of medium-duty truck collision with twin anti-ram bollards of steel tube is analysed and simulated with different mass-spring-damper models to study bollard design requirements. Test data is obtained from test report of a medium-duty truck crashed into two fixed twin bollards at speed 78.3 km/h. Maximum impact load and impact height at that time is important in the analysis. Bollard height should be close to or larger than the vehicle's centre of gravity height to avoid climbing of the truck on the bollard. However, increasing impact height yields also increase in failure risk of bollard. Foundation is also critical in success of the bollard in successfully stopping the vehicle. The bollard should be fixed to the frame embedded in the concrete foundation so that the deformation in concrete be minimised. The bollard should be so stiff to stop the vehicle while most of the impact energy is absorbed by the vehicle through deformation of its frontal sections. A single-degree freedom linear mass-spring-damper model is the simplest model, but its results are not in line with test data. Single-degree non-linear model simulates the peak load but not the load history. However, using engine mass instead of truck mass in the single-degree model provides acceptable impact force data for the bollard. Two-degree freedom mass-spring damper linear model seems to simulate both truck's and bollard's deformation in a good manner. Non-linear analysis simulates the collision in a more realistic way, but it requires more data to be determined with testing. [ABSTRACT FROM AUTHOR]

Lack of shock absorption capability of conventional steel bollards causes significant vehicle damage and, consequently, high repair costs. This research studies a solution to reduce vehicle damage by inserting polylactic acid (PLA) honeycomb structures. A honeycomb-inserted bollard was designed based on numerical simulations using LS-DYNA, which yielded the bollard designed for actual vehicle-bollard collision experiments. Simulation efforts were focused on calculating the acceleration characteristics when a vehicle collides with steel and honeycomb-inserted bollards. Compared to the simulated steel bollards, 20 MPa yield-strength honeycomb-inserted bollard showed 0.017 s delay in the maximum acceleration occurrence time, reduction of the maximum acceleration of 37.4% of that of steel bollards, and a 13.1% reduction in the B-pillar maximum acceleration. Actual vehicle-bollard collision experiments, with a gyro-sensor installed at the test vehicle front bumper frame, also proved improved shock absorption characteristics of the honeycomb-inserted bollards. An experiment with honeycomb-inserted bollard showed a 0.783 s delay in the maximum acceleration occurrence time, a significant delay when compared to steel bollards. The maximum acceleration measured by the gyro-sensor was 0.35 × 103 m/s2 when the simulation predicted it to be 0.388 × 103 m/s2, proving the similarity in the simulations and experiments. Thus, this study of shock absorption characteristics promised reduced damage to vehicles and lower repair cost. [ABSTRACT FROM AUTHOR]

The blind encounter commuting risks, such as failing to recognize and avoid obstacles while walking, but protective support systems are lacking. Acoustic signals at crosswalk lights are activated by button or remote control; however, these signals are difficult to operate and not always available (i.e., broken). Bollards are posts installed for pedestrian safety, but they can create dangerous situations in that the blind cannot see them. Therefore, we proposed an obstacle recognition system to assist the blind in walking safely outdoors; this system can recognize and guide the blind through two obstacles (crosswalk lights and bollards) with image training from the Google Object Detection application program interface (API) based on TensorFlow. The recognized results notify the blind through voice guidance playback in real time. The single shot multibox detector (SSD) MobileNet and faster region-convolutional neural network (R-CNN) models were applied to evaluate the obstacle recognition system; the latter model demonstrated better performance. Crosswalk lights were evaluated and found to perform better during the day than night. They were also analyzed to determine if a client could cross at a crosswalk, while the locations of bollards were analyzed by algorithms to guide the client by voice guidance. [ABSTRACT FROM AUTHOR]