Characterizing the Dynamic Response of a Chassis Frame in a Heavy-Duty Dump Vehicle based on an Improved Stochastic System Identification

This paper presents an online method for the assessment of the dynamic performance of the chassis frame in a heavy-duty dump truck based on a novel stochastic subspace identification (SSI) method. It introduces the use of an average correlation signal as the input data to conventional SSI methods in order to reduce the noisy and nonstationary contents in the vibration signals from the frame, allowing accurate modal properties to be attained for realistically assessing the dynamic behaviour of the frame when the vehicle travels on both bumped and unpaved roads under different operating conditions. The modal results show that the modal properties obtained online are significantly different from the offline ones in that the identifiable modes are less because of the integration of different vehicle systems onto the frame. Moreover, the modal shapes between 7Hz and 40Hz clearly indicate the weak section of the structure where earlier fatigues and unsafe operations may occur due to the high relative changes in the modal shapes. In addition, the loaded operations show more modes which cause high deformation on the weak section. These results have verified the performance of the proposed SSI method and provide reliable references for optimizing the construction of the frame

A Flow Structure Interaction Method for Towed Cable System

Abstract: The ocean towed cable system is a classic example of fluid-structure interaction (FSI). This interaction can exhibit stability or oscillation between a highly deformable moving cable and the surrounding turbulent flow. However, in dynamic simulations of towed cable systems, a constant drag coefficient for an infinite circular cylinder is often used based on experimental data. An innovative fluid-structure interaction method is introduced to obtain accurate drag distribution along cable to couple with towed system dynamics. A modified nodal position finite element method (NPFEM) coupled with Reynolds-averaged Navier-Stokes (RANS) approach has been utilized to predict hydrodynamic forces along the cable. A data exchange algorithm has been developed specifically for fluid-structure interaction within the towed cable system where the cable profile is transferred to construct the flow domain while hydrodynamics is interpolated for NPFEM analysis. A topology partition around cable is applied. A multiblock grid is generated around cable. The simulation results of the fluid-structure interaction of the towing system are verified. This FSI scheme reveals how strongly hydrodynamics determine cable dynamics and induce vortex structure vibrations around a towed cable system. Parametrically controlled structured grid generation and their applicability for complex flow fields have also been discussed. Detailed descriptions of boundary layer separation evolution around spatially distributed cable are provided. This FSI scheme reveals a real strongly hydrodynamic determined cable dynamics and vortex structure induced vibrations around a towed cable system. The proposed method enhances predictive accuracy of the towed system dynamics response

The Orientational Influence on the Electronic Structure of the Solid fcc C_<60>

The comparison of the electronic structures of fcc C_ solids between two different molecular orientations has been done by performing a band structure calculation. We have found that the molecular orientation causes considerable changes on the degeneracies at Γ points, the dispersion of bands and the location of valence band maximum and conduction band minimum. The band variation upon molecular orientation should become an important subject in physics and materials science of the new class of solid fullerenes

Effect of pinocembrin pre-treatment on expressions of Cx43 protein and claudin 1 in myocardial ischemia cardiomyocytes of arrhythmic rats

Purpose: To investigate the effects of pinocembrin on ventricular rhythm and the expression of cardiomyocyte ligament junction protein (Cx43) and claudin 1 (ZO-1) in ischemia/reperfusion (I/R) rats.Methods: Ischemia/reperfusion (I/R) model rats (n = 15) were divided into 5 groups: IR group, control group, and 3 pinocembrin groups (3, 10 and 30 mg/kg). The serum levels of creatine kinase-MB isoenzyme (CK-MB) and troponin I (cTnI) were measured by enzyme-linked immunosorbent assay (ELISA). Changes in myocardial tissue were detected by H &amp; E staining, while mRNA and protein levels of Cx43, ZO-1 and Kir2.1 were measured by reverse transcriotion-polymerase chain reaction (RT-PCR) and Western blotting, respectively.Results: In pinocembrin groups, heart rate (HR), mean arterial pressure (MAP) and rate-pressure product (RPP) levels were significantly higher compared with IR group (p &lt; 0.05). Moreover, the extent of arrhythmia and the levels of CK-MB and cTnI in pinocembrin groups were lower relative to IR group, while Na+-K+-ATPase and Ca2+-Mg2+-ATPase activities, as well as Cx43 mRNA, ZO-1 mRNA, and protein levels of Cx43, ZO-1 and Kir2.1 were significantly higher than the corresponding values for IR group (p &lt; 0.05).Conclusion: These results suggest that pinocembrin reduces ventricular arrhythmias in I/R rats by upregulation of expressions of Cx43, ZO-1 and Kir21, and inhibition of re-distribution of ZO-1 and Cx43. These findings provide the basis for the clinical application of pinocembrin in the treatment of arrhythmia.Keywords: Pinocembrin, Ventricular arrhythmia, Ligament junction protein, Recombinant human Kir2.1 protein, Arterial pressure, Protein levels, Claudin, Cardiomyocyt

Cooperative coevolutionary bare-bones particle swarm optimization with function independent decomposition for large-scale supply chain network design with uncertainties

Supply chain network design (SCND) is a complicated constrained optimization problem that plays a significant role in the business management. This article extends the SCND model to a large-scale SCND with uncertainties (LUSCND), which is more practical but also more challenging. However, it is difficult for traditional approaches to obtain the feasible solutions in the large-scale search space within the limited time. This article proposes a cooperative coevolutionary bare-bones particle swarm optimization (CCBBPSO) with function independent decomposition (FID), called CCBBPSO-FID, for a multiperiod three-echelon LUSCND problem. For the large-scale issue, binary encoding of the original model is converted to integer encoding for dimensionality reduction, and a novel FID is designed to efficiently decompose the problem. For obtaining the feasible solutions, two repair methods are designed to repair the infeasible solutions that appear frequently in the LUSCND problem. A step translation method is proposed to deal with the variables out of bounds, and a labeled reposition operator with adaptive probabilities is designed to repair the infeasible solutions that violate the constraints. Experiments are conducted on 405 instances with three different scales. The results show that CCBBPSO-FID has an evident superiority over contestant algorithms