Performance Assessment and Comparison of Two Piezoelectric Energy Harvesters Developed for Pavement Application: Case Study

To advance the development of piezoelectric energy harvesters, this study designed and manufactured bridge-unit-based and pile-unit-based piezoelectric devices. An indoor material testing system and accelerated pavement test equipment were used to test the electrical performance, mechanical performance, and electromechanical coupling performance of the devices. The results showed that the elastic modulus of the pile structure device was relatively higher than that of the bridge structure device. However, the elastic modulus of the two devices should be improved to avoid attenuation in the service performance and fatigue life caused by the stiffness difference. Furthermore, the electromechanical conversion coefficients of the two devices were smaller than 10% and insensitive to the load magnitude and load frequency. Moreover, the two devices can harvest 3.4 mW and 2.6 mW under the wheel load simulated by the one-third scale model mobile load simulator, thus meeting the supply requirements of low-power sensors. The elastic modulus, electromechanical conversion coefficients, and electric performance of the pile structure device were more reliable than those of the bridge structure device, indicating a better application prospect in road engineering.

Dynamic Wheel-Rail Force-Based Track-Irregularity Evaluation for Ballasted Track on Serviced Railway by Adjacent Excavation

This study investigates a load-based, track-irregularity-analysis technique for ballasted tracks on a serviced railway line with respect to excavation work conducted in adjacent sites. A numerical analysis and field measurements (railbed-settlement-monitoring sensor, track-geometry-measurement system, wheel-load measurements) were analyzed comparatively to demonstrate the correlation between the track irregularities and the Wheel-Rail interaction force. In this way, we highlight the necessity for load-based track-irregularity-management methods. The analyzed results show that the maximum dynamic wheel load was measured in the range of approximately 10 m before and after the location where the maximum track irregularities occurred, and that even if the maintenance criteria of track irregularities were satisfied, the design dynamic wheel load could still be exceeded depending on the train speed, thus indicating that track damage can be caused by the impact load.

Analysis of the Cutting Abilities of the Multilayer Grinding Wheels—Case of Ti-6Al-4V Alloy Grinding

This paper presents an effectiveness analysis of the grinding process with the use of a new multi-layer abrasive tool. The designed abrasive tool consists of external layers with a conventional structure, whose task is to decrease the grinding wheel load and ensure high grinding volumetric efficiency. The inner layer of the grinding wheel contains a 30% addition of abrasive aggregates. The task of the inner layer is to provide lower roughness of the machined surface. The aim of the research presented in this paper was to evaluate the topography of the designed abrasive tool and to analyze the middle layer properties influencing the machined surface roughness. The differentiation of the active surface features of the abrasive tool was determined for the conventional layer and the layer with the addition of abrasive aggregates. The machining potential of the layers was also determined using the Shos parameter. The surface topography of Ti-6Al-4V alloys ground with the use of a multi-layer wheel and a conventional grinding wheel was analyzed. With the application of the bootstrap hypothesis, the set of roughness parameters differentiating the topography of ground surfaces was determined.

Concept and Development of an Accelerated Repeated Rolling Wheel Load Simulator (ARROWS) for Fatigue Performance Characterization of Asphalt Mixture

Fatigue performance is one of the most important properties that affect the service life of asphalt mixture. Many fatigue test methods have been developed to evaluate the fatigue performance in the lab. Although these methods have contributed a lot to the fatigue performance evaluation and the development of fatigue related theory and model, their limitations should not be ignored. This paper starts by characterizing the stress state in asphalt pavement under a rolling wheel load. After that, a literature survey focusing on the experimental methods for fatigue performance evaluation is conducted. The working mechanism, applications, benefits, and limitations of each method are summarized. The literature survey results reveal that most of the lab test methods primarily focus on the fatigue performance of asphalt mixture on a material level without considering the effects of pavement structure. In addition, the stress state in the lab samples and the loading speed differ from those of asphalt mixture under rolling wheel tire load. To address these limitations, this paper proposes the concept of an innovative lab fatigue test device named Accelerated Repeated Rolling Wheel Load Simulator (ARROWS). The motivation, concept, and working mechanism of the ARROWS are introduced later in this paper. The ARROWS, which is under construction, is expected to be a feasible and effective method to simulate the repeated roll wheel load in the laboratory.

Assessment Of Factors Affecting Road Pavement Design And Remedial Actions

Many factors such as number of vehicles, speed, climatic conditions and other factors affect are to be considered for the design of pavement. In this article we will discuss about the factors influencing pavement design. Pavements are engineered structures which are used as roads, runways, parking areas, etc. Ground or surface transportation is the most widely used transportation in the world. So, construction of pavements should be done as it is strong and durable for their design life. There are so many factors which influencing the pavement design. The factors may be of loading, environment, materials used etc. Which are as follows Wheel load, Axle configuration, Contact pressure, Vehicle speed, Repetition of loads, Subgrade type, Temperature and Precipitation. This paper aims to present a review on the performance, problems and possible remedial measures practices for roads constructed on these problematic soils in the country. Finally, emphasis should be given to the importance in construction in this kind of soil of strictly applying engineered design of geometric, drainage, pavement thickness, material selection and proportioning. Thus, those concerned bodies shall decide to accept and control the risk associated with construction on this soil or not, or to decide that more detail study is required to allow for extra design and construction preemptive measures once the potential problem has been identified and the end user convinced of the cost-savings in adopting a pro-active approach.

“Mechanistic Analysis of Rigid Pavement for Wheel Load Stresses By Finite Element Method Considering Different Sub-Grade with Different Percentage of Metal Fibre”

In the present work, analysis of concrete pavements using ANSYS software has been attempted. ANSYS is a finite element method-based software. The concrete slab has been modeled with solid 45 brick element and spring elements for soil. Analysis was carried out for a wide range of load and slab soil combination. The soil as “Winkler type” represented by elastic springs and their stiffness was derived from modulus of sub-grade reaction. The influence of any particular base or sub base on edge stresses was not studied here. The model will be then subjected to number of varying input parameters like the change in the thickness of pavement slab, sub-grade material to winkler foundation, modulus of elasticity by adding metal chips in different percentage like 10%, 20%, 30% and also intensity of loads. It is aimed to compare the stresses of the model study with classical approach of Westergaards and IRC 58- 2002 method. Westergaards equation under estimate edge wheel load stresses when compared with those obtained from ANSYS. For generating the charts, edge loading condition was considered which is critical case for wheel load stresses. Also, it was aimed to compare the results with those given by IRC 58 – 2002 design charts. Design charts were developed in thesis work yield the same value of pavement thickness as that of IRC 58 – 2002 method.

“Mechanistic Analysis of Rigid Pavement for Wheel Load Stresses By Finite Element Method Considering Different Sub-Grade with Different Percentage of Metal Fibre”

In the present work, analysis of concrete pavements using ANSYS software has been attempted. ANSYS is a finite element method-based software. The concrete slab has been modeled with solid 45 brick element and spring elements for soil. Analysis was carried out for a wide range of load and slab soil combination. The soil as “Winkler type” represented by elastic springs and their stiffness was derived from modulus of sub-grade reaction. The influence of any particular base or sub base on edge stresses was not studied here. The model will be then subjected to number of varying input parameters like the change in the thickness of pavement slab, sub-grade material to winkler foundation, modulus of elasticity by adding metal chips in different percentage like 10%, 20%, 30% and also intensity of loads. It is aimed to compare the stresses of the model study with classical approach of Westergaards and IRC 58- 2002 method. Westergaards equation under estimate edge wheel load stresses when compared with those obtained from ANSYS. For generating the charts, edge loading condition was considered which is critical case for wheel load stresses. Also, it was aimed to compare the results with those given by IRC 58 – 2002 design charts. Design charts were developed in thesis work yield the same value of pavement thickness as that of IRC 58 – 2002 method.