The design and optimization of the spring element (using FEA) of a new WIM sensor, proposed by ROC Systemtechnik GmbH is presented in the following sections [6�C8].3.?Initial WIM Sensor Model (7.1 mm Thickness of the Elastic Element)An innovative WIM sensor proposed by AZD9291 manufacturer the ROC Company has been conceived and it shows the following advantages [9]:Small cross section and flat design (90 mm ��24 mm);Good accuracy and repeatability;Good reliability;Moderate price;Low installation cost.Each sensor box designed as a matrix of 16 measurement points contains eight sensor modules representing the shear beam spring elements (Figure 2). In a WIM system, each lane of the road is equipped with a line of sensors, consisted of several WIM sensor boxes covering the whole lane width.Figure 2.A WIM sensor box.
The initial design of a sensor module is presented in Figure 3. The thickness of the module components and their elastic characteristics are given in Table 1. The overall dimensions of this assembly are 48 mm �� 18.7 mm �� 7.1 mm. It is composed of two outer plates, (1) and (5) as shown in Figure 3(a), and a central elastic plate (3), Figure 3(b), bonded together by the adhesive layers (2) and (4), Figure 3(c). To avoid the relative displacements between the three plates, three pins (6) are also inserted in the assemblage. The bottom part of the sensor module is embedded in the sensor box and the upper part is loaded by the tires running on the top pad of the box. The central elastic plate (3) is equipped with strain gages and their outputs are sent to a data acquisition system.Figure 3.
Components and assembly of a sensor module: (a) Outer plates; (b) Central elastic plate; (c) Assembly of sensor module [10].Table 1.The thickness of the sensor module components and their elastic characteristics.4.?Modelling and Data Processing in the FEA Stage4.1. Model and MaterialsFinite Element Analysis in the elastic range, under static loading conditions, has been performed using the ABAQUS v6.8 software. The elastic element has been considered to be embedded at the bottom part and leaned on the flat surfaces near the lower leg. The maximum load of 6,000 N, corresponding to the heaviest vehicle, was equally divided on the two arms of the elastic element and uniformly distributed on the top surfaces and the flat surfaces in their vicinity (Figure 4).
The three sensor plates are fixed with adhesive and three pins. The boundary conditions on the pin holes surface were connection (limited to longitudinal displacement AV-951 in the direction of OZ axis and rotation of OX, and OY axis). Initially, the outer plates and www.selleckchem.com/products/PD-0332991.html the central elastic plate have been made of stainless steel 1.4548.6 (X5CrNiCuNb17-4-4) Bohler N700, having the yield point ��0.2 = 1,170 MPa, considered a homogeneous and isotropic material.Figure 4.