STUDY OF THE BEHAVIOR OF TANK TRUCK WITH LIQUID CARGO IN CURVED MOVEMENT

The principles of calculating the stability margin and overturning moment to ensure the safe-ty of road traffic of a heavy-duty vehicle on curved road sections are considered. Two stages of the behavior of a fire-fighting tanker are considered: during slow sliding in a skid and the impact of the car's wheels on an obstacle, followed by overturning.

Probable Causes of Losses of Containers from Container Ships

In May of 2020 a container ship sailing along the eastern coast of Australia encountered a storm and lost a number of containers. The loss of containers was not unusual, about 1400 containers are lost each year on average. What was unusual was the large number of containers on this one ship. Coincidentally, MARIN releasted a report in September 2020 investigating similar losses of large number of containers from container ships going to northern Europe. Then, between October 2020 and February 2021, seven ships on a northern Pacific route from China to the USA loss between 3,000 and 4,000 containers and had a large number of container stacks roll over. This paper is a independent generic assessment of a marine forensic investigation taking a systems engineering approach to look at the broad spectrum of possible causes of container stacks rolling over and lossing containers. The paper discusses weather effects on the stability and motions of the container ships and the securing of the cargo containers. The paper goes into detail about the underlying issue of the container stacks and their heights such that at decreasingly smaller angles of heel or rll, the line of action of the weight of the higher containers passes outside the base of the stack thereby causing a overturning moment on the corners of the containers.

Wave Impact Loads on Vertical Seawalls: Effects of the Geometrical Properties of Recurve Retrofitting

This study investigates the variation of wave impact loads with the geometrical configurations of recurve retrofits mounted on the crest of a vertical seawall. Physical model tests were undertaken in a wave flume at the University of Warwick to investigate the effects of the geometrical properties of recurve on the pressure distribution, overall force, and overturning moment at the seawall, subject to both impulsive and non-impulsive waves. Additionally, the wave impact and quasi-static loads on the recurve portion of the retrofitted seawalls are investigated to understand the role of retrofitting on the structural integrity of the vertical seawall. Detailed analysis of laboratory measurements is conducted to understand the effects of overhang length and height of the recurve wall on the wave loading. It is found that the increase in both recurve height and overhang length lead to the increase of horizontal impact force at an average ratio of 1.15 and 1.1 times larger the reference case of a plain vertical wall for the tested configurations. The results also show that the geometrical shape changes in recurve retrofits, increasing the overturning moment enacted by the wave impact force. A relatively significant increase in wave loading (both impact and quasi-static loads) are observed for the higher recurve retrofits, while changes in the overturning moment are limited for the retrofits with longer overhang length. The data generated from the physical modelling measurements presented in this study will be particularly helpful for a range of relevant stakeholders, including coastal engineers, infrastructure designers, and the local authorities in coastal regions. The results of this study can also enable scientists to design and develop robust decision support tools to evaluate the performance of vertical seawalls with recurve retrofitting.

Practical confirmation of mechanical balancers effectiveness to reduce vibration of marine main diesel engines

The article discusses compensators of unbalanced moments from inertial forces of the second and variable components of the overturning moment of the main order and the elastic moment at the resonance of torsional vibrations of the shaft line of modern marine low-speed diesel engines. The efficiency of the diesel engine’s operation is analyzed based on the vibration measurements on ships and some problems caused by these devices.

Seismic Performance of Storage Tank Isolated by Different Isolators Through Real-Time Hybrid Simulation

There are three kinds of isolators commonly used in storage tank, friction pendulum bearing (FPB), laminated rubber bearing (LRB), and variable curvature friction pendulum bearing (VCFPB), respectively. Real-time hybrid simulation is conducted in this paper to compare the seismic performance of the storage tank isolated by the above three types of bearings. The storage tank is used as the physical substructure for experimental testing, and the isolators are adopted as the numerical substructure for numerical simulation. The isolation performance is estimated by the following perspectives: deformation of the isolator, shear force, overturning moment, and input energy. Test results show that the deformation of LRB is the largest, which can be twice that of FPB, and that larger deformation will enlarge the seismic energy input into the storage tank. Moreover, the low-frequency components of shear force and overturning moment are amplified by LRB. In contrast, the FPB and VCFPB have a good performance on all frequency bands. Particularly, the softening mechanism enables VCFPB to have better seismic performance and have a reduction rate of about twice that of LRB.

Analysis of Multi-Story Buildings with Hybrid Shear Wall - Steel Bracing Structural System

Numerous studies were contemplated on the structures with distinctive structural configuration and ample amount of work is currently being performed through the investigation of the response of individual behavior of shear walls and bracings by varying configurations and their material properties. Seismic design philosophies had mentioned firmly that a structure must accomplish Life Safety (LS) and Performance Level (PL) for both reinforced concrete and steel structures. This study is anchored on prevailing lateral load resisting system which is virtuous but not adequate to retain vigorous ground motion or acceleration. To overwhelm this problem, an attempt was made to familiarize a new lateral load resisting system formulated by the amalgamation of two different existing lateral load resisting systems, specifically shear walls and bracings. The hybrid structural system embraces two distinctive lateral load resisting techniques, shear walls, and bracings for moment-resisting frame. A numerical finite element study was carried out by the linear dynamic method on the response of structure subjected to seismic condition and an optimal configuration of the different structural patterns is assured by using numerous possible patterns of a hybrid structural system using finite element-based software. The criteria contemplated for study including time period, base shear, overturning moment, story drift ratio, and story displacement are compared with different models and the optimal structure is concluded based upon the recital. The comparative results revealed that there is a reduction noticed in the fundamental time period, and story displacement, where as there is negligible increment in base shear and overturning moment for the hybrid structural system as compared to other configurated models.

A Review on Seismic Performance of L-Shaped Building Through Plan Irregularities

The patterns of sporadic structure development have quickly expanded because of tasteful and restricted accessibility of land. Past examinations have indicated that the structures with design abnormality are harmed under solid ground movement. Auxiliary inconsistencies are significant elements which decline the seismic exhibition of the structures. Structures having basic anomalies bring about the lopsided circulation of the story float, exorbitant twist, etc. The irregularity discussed here are about plan irregularity which is available in re-participant corners and torsional anomaly which is caused by abrupt changes in firmness and twist enhancement factor in building. This study is to propose a feasible solution to build this kind of structure in seismically active areas using analytical methods with the assistance of ETABS software. The analysis shall be done through a comparable static horizontal power technique and reaction range examination (dynamic investigation). The basic reactions will estimated regarding story displacement, inter-story drift ratio, torsional irregularity ratio, torsional diaphragm rotation, normalized base shear force, and overturning moment, which are also called seismic response demands. The structure will be analyzed and compare with different types of other shape plan.