Mounting System Research Articles

Engine to wing structural design under critical loads caused by a propeller blade loss

To support the propeller blade loss loads in a turboprop aircraft the engine mounting system has to be carefully designed. The joints have to withstand the flight loads, however, during the blade loss event they have to fail before the wing gets damaged. Using a FEM model and Monte Carlo simulation techniques the possible failure sequences for a broad spectrum of flight conditions have been obtained, including different propeller frequencies, blade loss sizes, angular positions where the blade is lost and also material properties. The structural model includes non-linear behavior, damages, and several types of failure together with stochastic variables which can incorporate parameter uncertainties. Finally, the pylon to wing support is designed to guarantee, with high level of confidence, no major hazard on the aircraft due to this dynamical phenomenon.

An optimization design method for a body mounting system of a heavy vehicle

Noise, vibration, and harshness is one of the main issues of heavy vehicles since their working conditions are very complex and tough. However, most previous works were focused on the optimization design methods of the engine mounting system and few works were reported to study those of the body mounting system. In practice, the body mounting system can significantly affect the noise, vibration, and harshness performance of the vehicle. An inappropriate body mounting system can produce unacceptable noise, vibration, and harshness performance and even result in serious accidents. To overcome this issue, an optimization design method for a body mounting system of a heavy vehicle is proposed to investigate the effect of the body mounting system on the noise, vibration, and harshness performance. Based on the geometrics of the vehicle body, the initial material parameters, shapes, and sizes of the rubber absorber of the body mounting system are determined by the vibration transmissibility ratio and static deformation ratio from an analytical method in the literature. The von Mises stresses of the initial rubber absorber cases from a static finite element analysis are used to select the optimal rubber absorber cases. A multibody dynamic method is proposed to validate the noise, vibration, and harshness performance of the optimal rubber absorber cases. The results show that the presented optimization design method for the body mounting system can be used to optimize the noise, vibration, and harshness performance of the heavy vehicles.

Design of Post-Consumer Modification of Standard Solar Modules to Form Large-Area Building-Integrated Photovoltaic Roof Slates

Building-integrated photovoltaic (BIPV) systems have improved aesthetics but generally cost far more than conventional PV systems because of small manufacturing scale. Thus, in the short and medium term, there is a need for a BIPV mounting system that utilizes conventional modules. Such a design is provided here with a novel modification of conventional photovoltaic (PV) modules to allow them to act as BIPV roofing slates. The open-source designs for the mechanical components necessary to provide the post-consumer conversion for a conventional PV module are provided, and prototypes are fabricated and installed on a mock roof system along with control modules mounted conventionally. The approximately U.S.$22/module BIPV roof-mounted system is direct mounted on the roof to eliminate the need for roofing shingles or other coverings, which effectively provides a 20% total cost reduction from conventional racking systems that demand a roof to mount upon without considering the savings from the rack itself. The results of the outdoor system testing found no water leaks. An increased operating temperature was observed, which would reduce the output from a silicon-based PV module by less than 10%. The results found significant potential for this design to further reduce total PV systems costs.

Vibration and noise analysis of heavy-duty trucks based on powertrain lightweighting

Vehicle lightweighting has been considered as one of the most important solutions to improve fuel economy and reduce harmful emissions. Considering the PowerTrain System (PTS) lightweighting of a heavy-duty truck tractor, cast iron of which the transmission shell was made is replaced with aluminum. Such weight reduction caused the irrationality of the natural frequency matching and the vehicle NVH performance become worse. In order to evaluate the influence of PTS lightweighting on the vibration and noise, the theoretical analysis and experimental tests have been done. The Genetic Algorithm (GA) method was adopted for the Powertrain Mounting System (PMS) optimization. Considering the installation position of PMS, the limitations of package space, cost and available time, the mounting stiffness was chosen as the design variables. One combination of the main vibration energy distribution of PMS was selected as the objective function of optimization design. After optimization, the vehicle experimental study was carried out to investigate the vibration and noise performance of the PMS at idle and Whole Open Throttle (WOT). The test results show that the optimization of PMS had a significant improvement on the vehicle vibration and noise performance.

Design method for a powertrain mounting system to decrease the vehicle key on/off vibrations

Five dynamic response evaluation indices from the viewpoint of the powertrain mount system and the vehicle system during the vehicle key on/off periods (i.e. the engine start and stop) are proposed. By analysis using different methods to minimize the powertrain vibration, it was found that an increase in the mount system damping can decrease the vehicle key on and key off vibration. For this reason, in this paper a semi-active hydraulic damping strut is designed and made which can provide high damping for a mount system when the vehicle key on/off but switches to lower damping to isolate high-frequency vibrations under normal conditions. The calculated longitudinal acceleration of the powertrain, the jerk of the powertrain, the dynamic force of the mount and the vibration dose value for a vehicle with the semi-active hydraulic damping strut and without the semi-active hydraulic damping strut are compared on the basis of the excitation force identified for the powertrain using a 13-degree-of-freedom vehicle model. Experiments were carried out, and the results show that the use of the semi-active hydraulic damping strut can decrease the engine start and stop vibrations to a large extent. Finally, the experimental results are compared with the calculated values from the 13-degree-of-freedom vehicle model.

Near-field partial shading on rear side of bifacial modules

It is well-known that near-field shading reduces the power output of a PV system drastically, especially when inhomogeneous shading creates a large current mismatch between series-connected solar cells. Typically, the front side irradiance is very uniform and near-field shading is avoided. In contrast, for bifacial panels, the rear side contribution is effected much more, both by the inhomogeneity of the rear irradiance and by (unavoidable) near-field objects, including the mounting system. In this paper, outdoor and indoor irradiance and IV measurements are combined with LT-spice modelling to show the limited effect of rear side shading on the performance. We will show that the actual rear side irradiance for an actual, tilted, equator-facing system, with cell-size resolution, varies between 47 and 83 W/m2. Varying distance and position of near-field objects, the drop in current is in good quantitative agreement with the measured reductions in rear side irradiance. Increasing the reflectance of the near-field object strongly reduces the effective shading, the measured loss in rear irradiance and the current drop in the IV curve.

Multi-objective robust optimization design for powertrain mount system of electric vehicles

A multi-objective robust optimization scheme for the powertrain mount system of an electric vehicle is proposed in this paper. A permanent magnet synchronous motor model is established by taking account of the effects of magnetic saturation and space harmonics, in which the d–q-axis inductance and the flux linkage excited by permanent magnet were obtained by finite element method. The rippled output torque of the permanent magnet synchronous motor mixed with harmonic components is obtained with the New European Driving Cycle as the running condition of the electric vehicle. A six degree-of-freedoms (DOFs) powertrain mount system is established and the response of the system is obtained with the rippled torque as the excitation input. A multi-objective optimization model of the powertrain mount system is built with the stiffness’s of the mounts as the design variables, and with the goal of maximizing the decoupling rates and minimizing the dynamic reaction forces of the mounts acting on the car body. Genetic algorithm is used to conduct the global optimization and all the Pareto optimal solutions are found out based on the optimization theory, and the solution with the optimal robustness of dynamic reaction force is obtained by Latin hypercube sampling method. The results show that with the proposed multi-objective robust optimization scheme applied for the parameters optimization of the motor mount system, the decoupling rates increase obviously, the dynamic reaction force decreases apparently, and the optimization result shows good robustness. The optimization results can make the powertrain mount system of electric vehicles processing of optimal dynamic response characteristics correspondingly.

Vertical repositioning accuracy of magnetic mounting systems on 4 articulator models

Statement of problemResearch of the ability of a cast mounted on an articulator on maintaining the identical position of a cast mounted on an articulator after repeated repositioning is lacking, despite the possible effects this may have on the occlusion of a mounted cast. PurposeThe purpose of this in vitro study was to verify and compare the vertical repositioning accuracy of 4 different, commercially available articulator magnetic mounting plate systems. Material and methodsFour articulators and their associated magnetic mounting plates were selected for the study. These were the Artex AR articulator (Amann Girrbach AG), the Denar Mark II articulator (Whip Mix Corp), the Kavo Protar Evo articulator (Kavo Dental GmbH), and the SAM3 articulator (SAM Präzisionstechnik GmbH). Three new magnetic mounting plates were prepared for each articulator system. The repositioning accuracy of each mounting plate was evaluated by comparing the standard deviation of the vertical distances measured between the mounting plate and a laser displacement sensor. The lower arm of the articulator was secured, and the vertical distance was measured by positioning the laser displacement sensor positioned vertically above the mounting plate. Once the vertical distance was measured, the mounting plate was detached from the articulator and reattached manually to prepare for the next measurement. This procedure was repeated 30 times for each of the 3 magnetic mounting plates. Data were analyzed by ANOVA for 2-stage nested design and the Levene test (α=.05). ResultsSignificant differences were detected among articulator systems and between magnetic mounting plates of the same type. The standard deviations of the measurements made with the Artex AR articulator, Denar Mark II articulator, Kavo Protar Evo articulator, and SAM3 articulator were 0.0027, 0.0308, 0.0214, and 0.0215 mm, respectively. Thus, the repositioning accuracy could be ranked in the order as follows: Artex AR, Kavo Protar Evo, SAM3, and Denar Mark II. ConclusionsThe position of the magnetic mounting plate after repositioning did not maintain an identical position in the vertical dimension on any of the 4 articulator models tested. The repositioning accuracy of the mounting plates showed significant differences among the articulators tested in this study.

Electric motor-based crankshaft stop position control to suppress range extender start vibration in electric vehicle

Range-extended electric vehicles have the most complex noise and vibration problems since certain control strategies often make range extenders (REs) shut down or restart for the sake of better fuel consumption. This paper deals with this uncomfortable riding experience, especially during the range extender start phase. A control-oriented nonlinear model for the start–stop vibration analysis, including range extender mount system, engine–clutch–motor shaft system, engine inertia torque and force, engine friction torque, engine gas torque, engine manifold pressure, electric motor torque, and range extender controller, is thus built. In the developed model, a new estimation method for gas torque is proposed, where the initial crank angle is considered and the relevant equations are simplified. The method has proven to predict gas torque accurately without using a complex calculation process. According to the developed model, the active control method, crankshaft stop position control (CSPC) has been proposed. The crankshaft stop position is analyzed as well as the crankshaft movement with different speeds at top dead center is discussed, which lead to the design of the target curves for crankshaft movement during the stop phase. Based on the set-up model, CSPC is finally applied through the cascade control of the motor to evaluate the control effectiveness. The simulation outcomes demonstrate that CSPC can help the crankshaft to finally stop at the optimal initial crank angle, which effectively lessens the vibration in the next start phase.

Gas torque compensation control for range extender start-stop vibration reduction in electric vehicle

One of the key challenges with the development of range extended electric vehicles is the noise, vibration and harshness behavior, specifically the uncomfortable ride experience during the range extender starting and stopping. This article focuses on providing an active control method to address this critical noise, vibration and harshness issue. A control-oriented nonlinear model for the start-stop vibration analysis, including range extender mount system, engine-clutch-motor shaft system, engine inertia torque and force, engine friction torque, engine gas torque, engine manifold pressure, electric motor torque and range extender controller, is thus built. In the developed model, a new estimation method for gas torque is proposed, where the initial crank angle is considered as well as the relevant equations are simplified. The method is proved to predict gas torque accurately without the expense of complex calculation process. Based on the model, the mount system vibration response has been analyzed that the excitation of range extender block on vehicle body in x-direction is the most prominent. The concept of the active control method, gas torque compensation control, is thus introduced in detail to reduce such a system vibration during start-stop phase. According to the control principle, the torque compensation coefficient for gas torque compensation control is determined and the compensation speed range is analyzed. In order to evaluate the control effectiveness, gas torque compensation control is implemented in the set-up model. The simulation outcomes demonstrate that gas torque compensation control is effective in reducing the vibration generated during start-stop transitions.

Аж богдын нурууны физик газарзүйн тодорхойлолт

Mountain Aj Bogd is one of branch mountains the mount systems Mongol Altai, which is located at the middle part of Mongol Altai mountain. Mountain Aj Bogd is similar with surface typology, deposits, form relief, erosion and accumulation process, mountain side, dissection, age and land­scape of main mountains of Mongol Altai. Aj Bogd Mountain is a mounting system had existed which surrounding by valleys and depressions and related by kotal and pass from the main ridge of the Mongolian Altai mountains. The Aj Bogd Mountain segregated to the east by Gobi Khonin Us, to the north from the mountain Khubch by pass Zoolin Bogd and the Mongol Altai mountain by depressions of Alag lake, to the west from mountains Ikh Tayan by dale of the Tuhum,Tooroi, to the south by Nomingiin gobi. The highest peak of this mountain Aj Bogd is 3093.3 m high above the sea level. The relief and peak of a mountain is mostly cupola or plane shaped because of in longest time weathered by wind and water.

Experimental Investigation of Static Properties of Magnetorheological Elastomer

Magnetorheological elastomer (MRE) is a type of smart material made of natural or synthetic rubber filled with micron-sized magnetic particles. Its shear modulus and elasticity can be controlled by applying an external magnetic field. In this study, a mounting system model is used to obtain displacement transmissibility factor. In the experimental analysis, three different MRE samples are manufactured by varying the percentage of magnetic particles. The experimental investigations are carried out to characterize the quasi-static properties of these MREs by attaching them with universal testing machine in compression and tensile mode. In both modes, different currents and velocities are applied to the samples. From the experimental results, a proportional relationship has been observed among the resisting force from MREs and applied excitation current, displacement and velocity. In most cases, the force has increased with the increasing percentage of magnetic particles in the sample. However, the highest force is obtained from the sample with 30% magnetic particles, at 2 A current and velocity of 4 mm/min. The results observed in this research would be useful for vibration control in applications such as engine mounting system.

Quiet rim driven ventilation fan design

Auxiliary ventilation fans are commonly used as a form of temperature and humidity control of working environments. However, they often generate high noise levels that cause permanent hearing impairment from prolonged exposure. Dominant noise sources from ventilation fans such as noise due to the aerodynamic interaction of the fan with the struts to support the hub motor and the blade-duct tip gap can be eliminated using a rim driven fan. However, tones from blade steady loading and thickness and the broadband airfoil self-noise of the fan are not eliminated. This noise is proportional to the 4-6th power of the tip speed. Hence, the approach here is to design a ring driven ventilation fan that reduces the fan tip speed while optimizing the blade profile to retain aerodynamic performance. The fan design has been 3D printed and implemented using a motor mounting system to validate the predicted performance. The motor mounting system integrates the fan design, a bell mouth shaped duct and a brushless DC motor. The experiments show good agreement with the predicted mechanical power, axial flow, and radiated noise over a range of speeds. Results suggest that a ring driven fan reduces noise while maintaining aerodynamic performance.

Ira Dyer and the BBN Applied Research Division

Ira Dyer was one of the first hires by Leo Beranek for the fledgling company Bolt, Beranek and Newman (BBN). Ira in turn hired many of the now recognized pioneers in ocean, structural; and ocean acoustics and formed the BBN Applied Research Division. Members investigated all aspects of sound and vibration in ships, submarines, aircraft, and spacecraft. An example includes during the mid-1950s, Ira helped design the US Navy X-1 Submarine, a small four-man quiet diesel-electric submarine for ADM Rickover. BBN designed an innovative engine mounting system that quieted the vehicle and led the way for ultra-quiet submarines in the future Navy. This submarine is now on display at the Navy Submarine Museum at Groton, CT. Other contributions by members include SEA (statistical energy analysis) and criteria for modeling flow-excitation forcing functions to structural radiation. Ira created a golden era for acoustics at BBN.

Development of a portable cavity-enhanced absorption spectrometer for the measurement of ambient NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub>: experimental setup, lab characterizations, and field applications in a polluted urban environment

Abstract. A small and portable incoherent broadband cavity-enhanced absorption spectrometer (IBBCEAS) for NO3 and N2O5 measurement has been developed. The instrument features a mechanically aligned non-adjustable optical mounting system, and the novel design of the optical mounting system enables a fast setup and stable operation in field applications. To remove the influence of the strong nonlinear absorption by water vapour, a dynamic reference spectrum through NO titration is used for the spectrum analysis. The wall loss effects of the sample system were extensively studied, and the total transmission efficiencies were determined to be 85 and 55 % for N2O5 and NO3, respectively, for our experimental setup. The limit of detection (LOD) was estimated to be 2.4 pptv (1σ) and 2.7 pptv (1σ) at 1 s intervals for NO3 and N2O5, respectively. The associated uncertainty of the field measurement was estimated to be 19 % for NO3 and 22–36 % for N2O5 measurements from the uncertainties of transmission efficiency, absorption cross section, effective cavity length, and mirror reflectivity. The instrument was successfully deployed in two comprehensive field campaigns conducted in the winter and summer of 2016 in Beijing. Up to 1.0 ppb NO3+N2O5 was observed with the presence of high aerosol loadings, which indicates an active night-time chemistry in Beijing.

Optimization of Front Wheel Drive Engine Mounting System for Third Order Shudder Improvement

Optimization of Front Wheel Drive Engine Mounting System for Third Order Shudder Improvement

VIBRATION ANALYSIS OF A FLAT PLATE UNDER AERODYNAMIC LOADING

Aeroelastic instabilities may occur in aircraft surfaces, leading to fatigue or structure failure. Flutter is an aeroelastic instability that results in a self-excited divergent oscillatory behavior of the structure. A classical two-degree-of-freedom flutter is a combination of bending and torsion vibration modes. A flexible mount system has been developed for flutter tests with rigid wings in wind tunnel. This flexible mount has to provide a well-defined two-degrees-of-freedom system on which rigid wings encounter flutter. Experi-mental Modal Analysis (EMA) and Finite Element Model Analysis (FEM) were performed to verify the natural frequencies and modes prior to any wind tunnel flutter test. The equations of motion of the system were developed using Lagrange's equation. The critical flutter speed was determined by three different methods: the p-method for steady flow, the classical flutter analysis and the k-method for unsteady flow, and comparing with experimental results. قد يحدث عدم الاستقرار في أجنحة الطائرات مما يؤدي إلى الکسر او انهيار الهيکل بالکامل. وتعتبر الرفرفة أکثر أنواع عدم الاستقرارالتى تنشأ من التداخل بين قوى الهواء، والمرونة، وقوى القصور الذاتي. ولدراسة هذه الظاهرة نحصل على درجتان من درجات الحرية وهما عزم الثنى وعزم الالتواء وذلک عن طريق وضع انظمة مرنة وأخرى جاسئة ، ويتم وضع هذا النظام فى نفق هواء وذلک للحصول على هذه الظاهرة .ويتم استنتاج معادلات الحرکة عن طريق معادلة لاجرانج. ويتم حساب سرعة الهواء التى تحدث عندها هذه الظاهرة باستخدام ثلاثة طرق مختلفة، واحدة فى تدفق منتظم للهواء، والاثنان الأخريان فى تدفق غير منتظم للهواء

A Theoretical Investigation of the Influence of Powertrain Mounts on Transmission Torsional Dynamics

This paper investigates the effect of the powertrain mounting system on the linear and nonlinear torsional dynamical behaviour of a transmission system. To this aim, two dynamic models, one with rigid mounts and the other with flexible mounts, are presented and compared: the first model considers only the torsional dynamics of transmission and driveline, while the second model includes also a 3 degrees-of-freedom powertrain block. The mechanical coupling and interaction between the powertrain block and transmission system is discussed and formulated. These models are then analyzed in terms of vibrational mode shapes, natural frequencies and Frequency Response Functions (FRFs); a sensitivity analysis of the main transmission parameters, e.g. the gear ratio, is also presented. From the comparison of the two simulated configurations (with and without powertrain mounts) both in time and frequency domain, a significant interaction between the two subsystems is noticed, particularly in the vehicle acceleration signal. Neglecting the powertrain mounts may lead to underestimating the real vibration level. A nonlinear model of a dual clutch transmission, including the main backlashes present along the transmission path (clutch spline, gear meshes, synchronizers), is coupled to the powertrain mounting system model. Finally, the effect of mount stiffness on transmission NVH during critical manoeuvres is shown.

Development of a Virtual Multi-Axial Simulation Table to Enhance the Prognosis of Loads on Powertrain Mounting System During Durability Applications

Development of a Virtual Multi-Axial Simulation Table to Enhance the Prognosis of Loads on Powertrain Mounting System During Durability Applications

Automated Mounting of Pole-Shoe Wedges in Linear Wave Power Generators—Using Industrial Robotics and Proximity Sensors

A system for automatic mounting of high tolerance wedges inside a wave power linear generator is proposed. As for any renewable energy concept utilising numerous smaller generation units, minimising the production cost per unit is vital for commercialization. The linear generator in question uses self-locking wedges, which are challenging to mount using industrial robots due to the high tolerances used, and because of the fact that any angular error remaining after calibration risks damaging the equipment. Using two types of probes, mechanical touch probes and inductive proximity sensors, combined with a flexible robot tool and iterative calibration routines, an automatic mounting system that overcomes the challenges of high tolerance wedge mounting is presented. The system is experimentally verified to work at mounting speeds of up to 50mm/s, and calibration accuracies of 0.25mmand 0.1 ∘ are achieved. The use of a flexible robot tool, able to move freely in one Cartesian plane, was found to be essential for making the system work.