Research on split and evolution of acoustic cavity resonance frequency of rotating loaded tire

The tire acoustic cavity resonance noise (TACRN) is known to contribute to audible noise in the passenger compartment of a vehicle. In order to reduce TACRN effectively, its mechanism needs to be grasped better. In this paper, the calculation formulas of tire acoustic cavity resonance frequency for four different conditions such as static unloaded tire, static loaded tire, rotating unloaded tire, and rotating loaded tire are analyzed and verified by the simulation and experiment. In particular, the resonance frequency formulas of static loaded tire introducing inflation pressure and rotating loaded tire are proposed and verified, respectively, in this paper. And the influence of tire inflation pressure, load, and running velocity on splitting frequency are studied. Some new findings are described and discussed; for example, the first-order resonance frequency may split into four resonance frequencies in most cases, and may split into three resonance frequencies in certain cases when a loaded tire is rotating. And the existing conditions for three and four resonance frequencies are also discussed.

Development of Mathematical Functions to Predict Deflection of Radial and Bias Tractor Tires on Rigid Surface

The objective of this study was to develop mathematical functions to predict deflection for radial and bias tires. In order to develop the models, the data were obtained from the tire manufacturing companies and organized in Excel first and then transferred to Minitab® for stepwise regression analysis. The variables considered in the study were inflation pressure, load and tire width and overall diameter. Tire width (w) and overall diameter (d) was considered in a multiplication form. The tire deflection models in two different form (linear and non-linear) were developed for both, radial and bias tires. The model selection was achieved by three different criteria and % differences between the measured and predicted data. Based on the results of applying model selection criteria, the models for radial and bias tire in non-linear form were found to be adequate for predicting the tire deflection. The results from the stepwise analysis indicated that the load on tire was the predominant variable in the models and made the highest contribution to the prediction functions. The developed models were verified against to published literature data and found a good agreement.

Real-Life Outcomes of Coronary Bifurcation Stenting in Acute Myocardial Infarction (Zabrze–Opole Registry)

Percutaneous coronary intervention (PCI) of bifurcation lesions is a technical challenge associated with high risk of adverse events, especially in primary PCI. The aim of the study is to analyze long-term outcomes after PCI for coronary bifurcation in acute myocardial infarction (AMI). The outcome was defined as the rate of major adverse cardiac event related to target lesion failure (MACE-TLF) (death-TLF, nonfatal myocardial infarction-TLF and target lesion revascularization (TLR)) and the rate of stent thrombosis (ST). From 306 patients enrolled to the registry, 113 were diagnosed with AMI. In the long term, AMI was not a risk factor for MACE-TLF. The risk of MACE-TLF was dependent on the culprit lesion, especially in the right coronary artery (RCA) and side branch (SB) with a diameter >3 mm. When PCI was performed in the SB, the inflation pressure in SB remained the single risk factor of poor prognosis. The rate of cumulative ST driven by late ST in AMI was dependent on the inflation pressure in the main branch (MB). In conclusion, PCI of bifurcation culprit lesions should be performed carefully in case of RCA and large SB diameter and attention should be paid to high inflation pressure in the SB. On the contrary, the lower the inflation pressure in the MB, the higher the risk of ST.

Anchoring and migration of balloon in REBOA

A mechanical theory is described for a phenomenon in the surgical procedure of resuscitative endovascular balloon occlusion of the aorta (REBOA). In this procedure a balloon is pushed into the aorta by a catheter and then inflated in order to stop haemorrhage. One of the hazards of this procedure is the tendency for the balloon to migrate away from its intended position. This work examines the mechanics of balloon anchoring and migration by analysing the effects of pressure waves, the sheet flow and solid friction in the thin gap between the walls of the aorta and balloon. A viscoelastic model is adopted for the aorta wall for pressure waves between the left ventricle and the balloon. The lubrication approximation is used for blood flow in the thin gap between the walls of the balloon and aorta. Samples of quantitative predictions are discussed on how the inflation pressure and balloon characteristics affect the balloon anchoring and migration. The crucial roles of solid friction and balloon placement are pointed out, which should help in guiding the manufacturing of balloons and their usage in the field.

Experimental and Numerical Studies on the Inflatable Recyclable Anchor in the Tube Piece Type Based on the Soil-Anchor Interaction Mechanism

This paper deeply studies the characteristics and “uplift bearing capacity” of a novel type of inflatable recyclable anchor in the tube piece. The proposed novel inflatable recyclable anchor in the tube piece type comprises a metallic rod, an inflatable anchorage device, and a recovery device. Fifteen field uplift tests are conducted to investigate the effects of inflation pressure, thickness of the steel disc, embedment length, and time lapse between anchor inflation and pullout on “the uplift bearing capacity.” The results show that “the uplift bearing capacity” of the novel inflatable anchor in the tube piece type increases with the increase of inflation pressure, thickness of the steel disc, and embedment length. With the increase of inflation time, “the uplift bearing capacity” of the novel inflatable anchor experiences an increase after first experiencing a decrease. The finite element analysis method is used to establish a numerical analysis model of the inflatable anchor, and the distribution law of the tensile stress of the surrounding soil during the pullout of the anchor is analysed. Compared with the traditional grouted anchor, the proposed anchor has an obvious superiority in recyclability, reusability, and swifter formation of anchorage force and thus is a resource-saving and environmentally friendly anchor technology.

Reduction of Whole Body Vibration in a Wide Frequency Range Using Inflation Pressure Control of Air Bladder Cushion

Several types of interfaces like foam and inflated air cells exist to reduce the effect of mechanical vibration experienced in human-machine interfaces in different scenarios such as transportation. However, their vibration attenuation performance in a wide frequency range relevant to whole body vibration (1–80 Hz) leaves much to be desired. In this study, we investigate the effect of inflation pressure on the vibration attenuation behavior of an air cell cushion. An experimental setup capable of conducting frequency sweep tests and regulating inflation pressure in an air cell array cushion was developed. Frequency sweep tests were conducted at various inflations and the vibration transmissibilities at static inflations were plotted. A dynamic inflation scheme was developed based on the apriori knowledge of inflation dependent transmissibilities. Furthermore, the closed loop behavior of the inflation scheme was evaluated with a frequency sweep test. The resulting closed loop transmissibility indicated better vibration attenuation performance than any single static inflation for the air cell array cushion in the range of frequencies relevant to whole body vibration. This result lays the groundwork for potential air cell cushions which modify their inflation dynamically through a direct feedback from sensors like accelerometers to attenuate vibration in a wide frequency range.

Effect of Cover Crop, Slurry Application with Different Loads and Tire Inflation Pressures on Tire Track Depth, Soil Penetration Resistance and Maize Yield

Agricultural soils can be affected in their ecological functions by in-field traffic of agricultural machinery. A three-factorial research design was carried out in a field experiment to test the effect of slurry tanker filling level (filled, half-filled, empty), tire inflation pressure of the slurry tanker (high: 300 kPa, low: 100 kPa), and ground covering (+cover crop, −cover crop) on tire track and soil penetration resistance (averaged, 0–20 cm, 21–40 cm) after application on the fields in spring. Additionally, the effect on grain yield of the subsequent culture was considered. The total weight of the tractor slurry tanker combination was 16,470 kg (empty), 25,940 kg (half-filled), and 34,620 kg (filled). The low tire inflation pressure of the slurry tanker increased the mean tire–soil contact area by 75% (filled), 38% (half-filled), and 16% (empty tanker). The results obtained show a significant effect of tire inflation pressure and ground covering on the measured parameters. The tire inflation pressure reduction effect on track depth was highest in the filled slurry tanker (−17.8%). With increasing wheel load, the effect of reduced tire inflation pressure on soil penetration resistance (0–20 cm) increased. In the subsoil (21–40 cm), the effect of tire inflation pressure was much lower, indicating that a reduction of tire inflation pressure preserves the upper layers rather than the lower ones. Furthermore, cover crops are linked to a higher degree of soil deformation after traffic with the tractor–slurry combination due to their loosening effect on the topsoil. Tire tracks were 15.0% deeper in the cover crop field than in the field without a cover crop. It is assumed that cover crop mixtures with different types of root mass can influence the mitigation of soil compaction in an ameliorative way.

Soil compaction response to wheel traffic in the Rolling Pampas region of Argentina

The present work shows the effects of the different agricultural wheels traffic on the soil physical properties on a Typic Argiudoll soil worked under no-tillage cropping system. Soil compaction produced by traffic was quantified through these parameters: a) cone index, b) rut depth and c) soil water content at the traffic moment. Grain chaser, sprayer, harvester combine and tractor equipped with commonly used wheels in the study area were tested. The main results obtained showed that the tyres with the highest inflation pressure and tyre ground pressures produced the highest values of cone index and rut depth. Typic Argiudoll soil worked under continuous no-tillage cropping system is not able to constrain topsoil and subsoil compaction when it is wheeled by tyre with ground pressures greater than 77.6 kPa. Highlights Soil compaction causes a reduction in root growth and yield in many crops. Soil under a no-tillage system does not limit topsoil and subsoil compaction when wheeled by tyres with ground pressures greater than 77.6 kPa When the machinery load increases on soils with high bearing capacity (soils under a long-term no-tillage system), the subsoil compaction problems increase.

Paradoxical Response of Pulmonary Slowly Adapting Units During Constant Pressure Lung Inflation

Typically, unit discharge of slowly adapting receptors (SARs) declines slowly when lung inflation pressure is constant, although in some units it increases instead-a phenomenon hereinafter referred to as creeping. These studies characterize creeping behavior observed in 62 of 137 SAR units examined in anesthetized, open-chest and mechanically ventilated rabbits. SAR units recorded from the cervical vagus nerve were studied during 4 seconds of constant lung inflation at 10, 20 and 30 cmH2O. Affected SAR units creep more quickly as inflation pressure increases. SAR units also often deactivate after creeping, i.e., their activity decreases or stops completely. Creeping likely results from encoder switching from a low discharge to a high discharge SAR, because it disappears in SAR units with multiple receptive fields after blocking a high discharge encoder in one field leaves low discharge encoders intact. The results support that encoder switching is a common mechanism operating in lung mechanosensory units.

Illustrating Membrane-Dominated Regimes in Pressurized Thin Shells

Pressurized thin-wall structures cover a broad range of applications, including storage tanks, pressurized rubber flood barriers, and large span enclosures. To accurately model such structures, the analyst must select the appropriate mechanical formulation (e.g.membrane vs shell). Membranes are assumed to have negligible bending stiffness and respond to compression by wrinkling; shells resist axial compression (before buckling) and bending efficiently. While theoretical research on these differences is vast, this study aims to explicitly clarify the consequences of this choice and permit a comparison of error between membrane and shell formulations. Therefore, this paper presents a parametric study of canonical pressurized thin-wall structural geometries (i.e.semi-cylinder, hemisphere) to illustrate the transitions between membrane and bending dominant behavior. The mathematical models of a pneumatic 5-parameter shell and membrane are presented and employed to quantify the effects of variables such as thickness and geometry on the amount of membrane, bending, and shear energy. The effects of inflation pressure, self-weight, and hydrostatic loads are also considered. The graphical results, presented in terms of dimensionless quantities in the design space, are general and should be of interest to the theorist and practitioner alike.