Assessment of the strength of the cabin mounting elements of the high-capacity wheeled chassis

The article deals with the issues of modeling the stress-strain state of the attachment points of the cab of a wheeled chassis of high load capacity. The main design loads are determined. Geometric and computational finite element models are constructed, taking into account the features of the metal structure. The technique of gluing elements of the grid model is applied. The contact interaction of the parts is taken into account. Based on the calculations performed, conclusions are drawn about the compliance of the developed structure with the strength requirements.

Structural analysis of freight car lever transmission with parallel shoe releasing devices taking into account the edge contact of the shoe and wheel

The article deals with the issues of modeling the stress-strain state of the attachment points of the cab of a wheeled chassis of high load capacity. The main design loads are determined. Geometric and computational finite element models are constructed, taking into account the features of the metal structure. The technique of gluing elements of the grid model is applied. The contact interaction of the parts is taken into account. Based on the calculations performed, conclusions are drawn about the compliance of the developed structure with the strength requirements.

HAZARD IDENTIFICATION AND PROBABLISTIC SCENARIO SELECTION FOR SHIP- SHIP COLLISION ACCIDENTS

In collision risk-based design frameworks it is necessary to accurately define and select a set of credible scenarios to be used in the quantitative assessment and management of the collision risk between two ships. Prescriptive solutions and empirical knowledge are commonly used in current maritime industries, but are often insufficient for innovation because they can result in unfavourable design loads and may not address all circumstances of accidents involved. In this study, an innovative method using probabilistic approaches is proposed to identify relevant groups of ship-ship collision accident scenarios that collectively represent all possible scenarios. Ship-ship collision accidents and near-misses recently occurred worldwide are collated for the period of 21 years during 1991 to 2012. Collision scenarios are then described using a set of parameters that are treated individually as random variables and analysed by statistical methods to define the ranges and variability to formulate the probability density distribution for each scenario. As the consideration of all scenarios would not be practical, a sampling technique is applied to select a certain number of prospective collision scenarios. Applied examples for different types of vessels are presented to demonstrate the applicability of the method.

HIGH-SPEED WAVE-PIERCING CATAMARAN GLOBAL LOADS DETERMINED BY FEA AND SEA TRIALS

Wave-piercing catamaran hull forms are widely used for high-speed ferry applications due to the hull slenderness, suitable for achieving high speeds. The global loads acting on these craft are of great interest as there is limited knowledge on determining the magnitude of the loads, in particular when operating in random sea conditions. Longitudinal and transverse bending moments as well as pitch connecting moments and hull torsion loads act on the hull simultaneously. This paper investigates the estimation of these global loads from full-scale catamaran sea trials strain gauge data using finite element methods. Det Norske Veritas (DNV) load cases are applied to a finite element model in order to determine the conversion between local strain values observed during sea trials and prevailing global loads. Comparisons are thus made of global loads determined from strain data collected from sea trials with DNV global load cases. The results show that this method is relatively reliable for the prediction of hull global loads in the absence of slamming. Comparisons have been made for different heading angles. The quasi-static design loads are important during the ship design stage, as they are good proxies in wavelengths comparable to the hull length for rationally determined loads obtained from a first-principles dynamic analysis. The broad aims here are to demonstrate the use of strain sensor data obtained during sea trials for determination of global sea loads, to reconcile the loads thus determined with DNV load cases and thereby to improve the accuracy of the predicted loads used in design to increase the structural efficiency of vessel design.

Inverted pyramid Azores - an eternal hybrid structure

Engineering structures are designed with observation of rules for structural performance under specific design loads, defined in the so-called structural codes. While dead loads are directly dependent from the selection of structural materials to a given structural function, live and accidental loads are often linked to the region where the structure must perform. In a complete opposition to engineering principles in Ancient Egypt, the inverted pyramid was designed to become a statement of how to bend gravitational laws, and what can be achieved by modern engineering, sill with intelligence to fulfill its function in a region where engineering structures are subjected to extreme live and accidental load regimes, e.g. high risk of earthquakes and high wind seasonal loads. A hybrid structural concept was specified, comprising lightweight structural wall elements anchored to a relatively heavyweight structural core. The suggested design concept fulfills the global equilibrium equation defined by architecture, and should become a structural example from a structural design perspective. As any other project involving non-comprehensive geometry, design and construction of the inverted pyramid is highly sensible to management options, which shall assure high precision manufacturing, and accurate control of its production.

Classification of Slamming Events in Irregular Waves Measured through Tow Tank Experiments

Slamming events are the source of critical design loads for small, high-speed craft. Categorization of slamming events can prove useful by identifying cases of interest for more in-depth analysis, such as high-fidelity modeling and experiments. Inspired by developments in facial recognition techniques, a quantitative method is proposed to sort slamming events using various experimental measurements. A singular value decomposition method on a matrix assembled of vectors of time-histories of rigid body motions recorded in free-to-heave-and-pitch tow tank experiments on a planing hull. While some of the categories identified in this work show distinct features in slamming accelerations consistent with previously identified categories, other categories have also been identified. These results can be used when evaluating ride quality, and design loads, and performing more in-depth studies on specific slamming categories.