Diagnosing mechanical damages not detected by the OBD system of diesel engines

The paper presents the possibilities of diagnosing with the use of vibracoustic signal of mechanical damages of diesel engines, which are not detected by the OBD system. This system does not recognize such damages, but it masks them delaying information about the damage to the point where the regulatory values of controlling work of the engine will exceed the limit values. This is because the aim of the OBD system is to ensure the minimization of exhaust emissions. There were made measurements of vibroacoustic signal of the head of the car engine with fuel injection system Common Rail, where there were introduced mechanical failures typical and dangerous for the engine. It has been proved that the OBD system does not recognize these damages and the work of the engine is correct. Therefore, there is a need for an additional diagnostic system which supports the OBD system in detection of this type of damages. It seems that the use of vibroacoustic signal as an additional analyzed signal should improve the sensitivity of the on-board diagnostic system to damages of diesel engine. The author tested the sensitivity of vibroacoustic signal to damages introduced to the engine and he presented the proposition of the system based on simple measures of the vibroacoustic signal, which allows for both detecting mechanical damages and their identification

Automatic system for measuring shifts and deformation of dental prostheses

The paper presented a multi-purpose system for testing of dental prostheses within the static and kinematic conditions as well as the conditions of its stability quick analysis. The common goal of prosthetics specialists is to define biomechanical criteria shaping the restorations to protect the existing state of the biological substrate [1]. In prosthesis biomechanics, the gingival soft tissue, as substances with heterogeneous properties, are difficult to individual assessment of the value, direction and duration of the occlusion forces transmitted by the prosthesis in the life cycle [2]. More predictable are static or kinematic behaviors, reflecting the mechanical states of prosthesis design with designed shape and material properties which are possible to determine. However, static measurements of dentures do not reflect their work in natural conditions [3], and can only designate the values of selected parameters (deflection, stress) during the reference of constant load values. The article presents the author’s research stand for kinematic loads testing, which are similar to natural ones during shredding of food. The results of stress and strain of denture prosthesis, identified during laboratory tests, will be used to verify the mathematical models of dentures during kinematic forces

Analysis of dynamic compliance of the supporting structure for the prototype of organic Rankine cycle micro-turbine with a capacity of 100 kWe

The article describes the research carried out using a complex numerical model which had been developed applying finite element method (FEM). The supporting structure on which two turbine generators (with a target capacity of approx. 100 kWe) were placed was the object of this study. The calculations were aimed to determine the influence of dynamic properties of the supporting structure on the operation of turbogenerators. Within this study the following tasks have been accomplished: computational modal analysis was performed, the stiffness coefficients of the tested construction were determined and compared with the dynamic properties of the bearings used. This was necessary in order to analyze the dynamic interaction between the rotor and the turbine’s bearings

Underwater robotic system for reservoir maintenance

In this paper a description and practical implementation of the developed prototype of an underwater hybrid robot is presented. The solution is based on the guidelines of Cracow waterworks (Municipal Waterworks and Sewer Enterprise, MPWiK S.A.). The prototype of the hybrid robot consists of a crawler robot and a ROV. Robots’ design, mathematical models of kinematics and dynamics of the crawler robot, ROV’s vision system architecture with image processing methods for surface crack detection and robot position and attitude estimation are investigated and examined. Results obtained from experimental validation of the developed prototype are presented and discussed. Finally, the paper establishes future research directions

Vision-based measurement systems for static and dynamic characteristics of overhead lines

In the paper, optical-based measurement methods for calculating the deflection and vibration of overhead lines are presented. The authors describe the state of the art in the field of non-contact examination of static and dynamic overhead transmission line characteristics, and propose concepts of vision-based measurement systems for both static and dynamic states of a structure. The system devoted to static measurements is based on a digital SLR camera and image-processing software used for the acquisition and interpretation of data. The digital image correlation method, implemented in Wiz2D software, is applied to compute the displacement of the transmission line cable with respect to a known baseline position. Dynamic characteristics of the structure are obtained using a stereo-vision system consisting of two high-speed digital cameras. Corresponding points in two video sequences of the vibrating cable are tracked using TEMA software. 3D positions in a camera frame of reference and displacements are computed using a 3D reconstruction method. The paper describes two series of experiments conducted on a lab setup and the obtained results are examined and discussed