The strain gauge method and the digital image correlation (DIC) method are commonly employed for measuring strain in tested objects, including material specimens and structural elements. The optical method enables the assessment of 3D strain fields across the entire area of interest, achieved through cameras and advanced software. The study investigates both quasi-static strength tests and more advanced research of structures. It explores full-scale construction testing, featuring highly stressed components of new wagon designs. The paper reviews the benefits and challenges of using the DIC method to measure large-scale elements. Conducting full-scale object testing is characterized by significant complexity, often involving interactions between elements, complex loading conditions, and the influence of friction. Numerous factors affect the measurements. Therefore, to compare both methods, an initially standard shear by tensile test of CFRP composite was analyzed. The analysis of strain maps provides valuable visualization of deformation patterns occurring during construction loading. The strain gauge method was crucial for verifying the quality of the DIC measurements. The results obtained provide a detailed understanding of how the components behave, highlighting the versatility of digital image correlation technology. For strain values of 0.3% and above, a good match was obtained between optical and strain gauge measurements. Below this value, the results have less accuracy. The results obtained provide a detailed understanding of how the components behave, highlighting the versatility of digital image correlation technology. The error comparison and discussion between different measurement scenarios were conducted. The paper presents a developed methodology for measuring strain and displacement state in complex and crucial structural elements. The method can be applied to measurements of heavily loaded components used in the transportation industry; for example, in railways.

A special wagon with a low rotatable loading platform for transportation of truck vehicles by rail was developed in Military University of Technology in the Department of Mechanics and Applied Computer Science in Warsaw. The essence of such reloading is to place the semitrailer on a special rotatable platform with the use of a truck tractor. The structure can be used for transportation of different types of vehicles such as tractors, trucks, trailers, semitrailers and cargo containers. The wagon allows quick and fast loading and unloading without any platform infrastructure or terminals. An intermodal transport system based on an innovative concept of the railway wagon, which will use the national railway infrastructure, was developed. The process of loading and unloading the trailers can be performed considering a whole train or individual wagons from any part of the train (no cranes needed). This type of railway wagon will allow transport companies to save time and money for road transport. The advantages of this construction are reduction of the negative impact on the environment as well as an increase of road safety by reducing the number of vehicles on the roads. As part of the work on the wagon and the intermodal transport system, a strength test of the wagon structure was carried out and the effort of the basic components of a the wagon and a complete structure was estimated. For this purpose, numerical analysis was used.

A special wagon, presented in the paper, can be used for intermodal transport of various types of vehicles. It enables transport of vehicles of 36 tons mass and height of 4m on the GB1 clearance height. An innovative wagon is equipped with a frame-support with marginal parts mounted on standard biaxial bogies and the central part lowered with a rotatable loading platform. The rotating part of wagon acts as a kind of platform, allowing truck to move through it during load/unload. During railway operation, this rotating platform is to become an integrated part of the wagon; the tailboards of the rotating part will be connected to the over-bogie part with the special locks. A unique concept of the wagon structure forced a design approach which was rather unusual for the rail industry. Since the design team aimed at very challenging demands of GB1 envelope and usage of standard bogies, the layout of the wagon had to be thoroughly examined in terms of its overall stiffness. Every major design change had to be simulated in order to accurately predict its influence on the whole wagon structure. FE analysis was used for numerical tests of such a wagon structure in different configurations. The calculations were carried out on the basis of PN-EN standards. Selected results of numerical tests of the prototype version of a such wagon for intermodal transports were presented in the paper.

The paper presents the study of the operation of the prototype of the dual leaf spring that consists of a four-leaf main spring and a two-leaf auxiliary spring under the action of a cyclic load close to the actual operating conditions of a car suspension. The importance of friction in an operation of this type of structure has been mentioned; numerical methods and an experimental facility for studying the effect of friction on the spring operation have been considered. The investigation results have been presented in the form of summary tables, color-coded images, and diagrams of the temperature distribution for measuring points located on single leaves of the double spring. The methodology of experimental studies and the used equipment made it possible to evaluate the effect of friction and accompanying thermal stresses during the operation of the dual leaf spring.

This article presents a simulation study of the suspension system in a vehicle that weighs approximately 12 tons (class N2). The authors have tested the influence of experimentally determined values of friction coefficients on the energy dissipated in the multi-leaf spring. The study was carried out using finite element analysis with LS-DYNA software. A nonlinear vibration model of the complete spring was developed, including the variable friction forces between the leafs. The model takes into account the sprung and unsprung mass of the chassis. Numerical tests were carried out using three different coefficients of friction (determined experimentally) for a selected speed of the car. Random realizations of the road micro-profile (type A, B, C) recommended by ISO 8608 were used. The results of the tests were presented in the form of acceleration curves in the vertical direction, comparative plots of daily vibration exposure A(8) and vibration transmission coefficient (T), and the distributions of RMS acceleration in frequency of one-third octave bands. This data was used to assess the quality of the vibration isolation system between the front suspension of the vehicle and the driver’s seat.

The article deals with investigations of a prototype single and double multi-leaf spring composed of a four-leaf main spring and a double-leaf supporting spring subjected to the cyclic loads. A methodology of a measurement conducted during experimental tests and a set of research instruments used in the stand research allow evaluation of the effects of friction and the accompanying heat stress of the leaf spring in the quasi real operating conditions. The role of clearances and friction in operation of this type of construction as well as analytical, numerical, and bench testing methods used in the research on the effect of energy dissipation due to friction on operation of the leaf spring are discussed. Dynamic elastic characteristics with hysteresis loops and identification of leaf cooperation areas are presented for the single and double multi-leaf springs tested under different conditions.