Tire–road coefficient of friction is often used to estimate stopping distances and other aspects of accident reconstruction. The actual value that must be used in the calculations is often obtained from published data and sometimes measured on-site. While it depends mainly on tires, road surface, ambient conditions and speed, the effective stopping capability of a vehicle is influenced also by other parameters (car, driver, ABS, etc.). This paper presents a methodology that, exploiting data obtained with on-site measurements and/or published by technical press, allows the evaluation of the coefficient of friction and the stopping capability of a car. This is done by means of a computer program, based on a fuzzy logic approach.

Hybrid supercapacitors (HSCs) are innovative energy storage solutions that are becoming essential in many fields of applications. Their performances are strongly influenced by several parameters, such as temperature conditions, load characteristics, and state-of-charge (SOC). For this reason, it is becoming fundamental to characterize their performances under different scenarios. One of the best ways to investigate the performances is by employing the electrochemical impedance spectroscopy (EIS) measurement. However, since HSC is a recent technology, databases and studies focused on impedance analysis are not currently available in the literature. For this reason, this work presents the results of a large measurement campaign carried out to acquire impedance data on a large frequency range (from 1 mHz to 100 kHz) under different temperatures and SOC conditions. The constructed dataset has been used to investigate impedance anomalies and to analyze the effects that temperatures and SOC may have on the HSC impedance. The large obtained dataset can also be used for diagnostic and prognostic purposes. The dataset used in this study is available at https://doi.org/10.6084/m9.figshare.24321496 .

Classic circuit modeling for supercapacitors is limited in representing the strongly non-linear behavior of the hybrid supercapacitor technology. In this work, two novel modeling techniques suitable to represent the time-domain electrical behavior of a hybrid supercapacitor are presented. The first technique enhances a well-affirmed circuit model by introducing specific non-linearities. The second technique models the device through a black-box approach with a neural network. Both the modeling techniques are validated experimentally using a workbench to acquire data from a real hybrid supercapacitor. The proposed models, suitable for different supercapacitor technologies, achieve higher accuracy and generalization capabilities compared to those already presented in the literature. Both modeling techniques allow for an accurate representation of both short-time domain and steady-state simulations, providing a valuable asset in electrical designs featuring supercapacitors.

When measuring residual stresses using the hole-drilling strain-gauge method, plasticity effects arise if the residual stress level exceeds about 60% of the material yield strength. In this case the classical methods, which are based on the linear elastic material behavior, do not work properly and residual stresses are overestimated. This paper presents a numerical study of the influence of plasticity on residual stress measurement by using the hole-drilling strain-gauge method in those cases in which stress does not vary with depth. The study investigates the effects of the most important loading, measuring, geometry, and material variables. An iterative method, which can be applied to obviate these errors, is then presented. The method was implemented in ANSYS using the APDL macrolanguage (ANSYS Parametric Design Language Guide, Documentation for ansys 11.0) to automatically execute the procedure steps. A finite element model of the hole, which allows for plasticity, is requested. Employing the readings of a standard three elements strain-gauge rosette, the method makes it possible to extend the measurement limit in comparison to that of the ASTM E837 standard (ASTM E837-08, “Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gauge Method”).