Adams Model Research Articles

Transient Co-Simulation of Low Voltage Circuit Breaker With Permanent Magnet Actuator

A new type of low voltage circuit breaker with permanent magnet (PM) actuator is proposed. The magnetic field is computed using finite element method (FEM) to find out the relationship among the flux linkage, displacement and different currents and these information are stored in a look-up table. The control model, which is built in Matlab, is connected with the Adams model via input and output interfaces. The transient co-simulation is used to study the making process. Experiments are carried out on a prototype to validate the proposed method.

Impact of the cavitation model on the theoretical performance of heterogeneous slip/no-slip engineered contacts in hydrodynamic conditions

Today's industry faces intense pressure to reduce energy consumption and to extend components' lifetimes in order to reduce economic and environmental costs. During the last few years, it has been pointed out that fluid wall slip is likely to improve friction in low-loaded mechanisms; if the slip zone covers only a specific zone of the surface, improvement of both load and friction can be obtained. The physico-chemical heterogeneity of the surface acts as a geometrical discontinuity and induces pressure gradients analogous to those occurring in a Rayleigh step bearing. Such favourable behaviour can be inhibited if the location of the slip/no-slip areas causes cavitation. This article aims to show the importance of the choice of the cavitation model in the analysis of slip/no-slip hydrodynamic contacts. Current practice predicts the performance of cavitated devices by using the well-known Half-Sommerfeld or Swift—Stieber models. However, using a mass-flow conserving model such as the so-called Floberg—Elrod—Adams model can lead to qualitatively and quantitatively different conclusions. The simple case of a parallel slider bearing is of particular interest. If alternating slip/no-slip areas are introduced, then a non-zero load-carrying capacity can be obtained whose theoretical value dramatically depends on the cavitation model and even on the inlet flowrate of the lubricant.

2-D analytical model for characterizing flexural damping responses of composite laminates

Abstract The flexural damping behaviors of composite laminates were characterized analytically in this study. A 2-D analytical model was developed based on the extension of Ni–Adams model [Ni RG, Adams RD. The damping and dynamic moduli of symmetric laminated composite beams—theoretical and experimental results. J Compos Mater 1984;18(2):104–21] accounting for the energy dissipation contributed by the laminar stresses of σxy and σyy. The specific damping capacity (SDC) of the composite was determined in accordance with the energy dissipation concept, which was defined as the ratio of the dissipated energy to the stored energy for per circle of vibration. The 2-D analytical model was validated by comparing the SDC of [0/−60/60]s and [0/90/45/−45]s laminates with the experimental data and the finite element (FEM) results. In addition, the effects of interlaminar stress on the flexural damping responses of laminated plates were also characterized in the 3-D FEM analysis. Results indicated that the interlaminar stress effect may not be so significant that the current 2-D model is adequate for the evaluation of the damping responses of the composite laminates. Furthermore, the present predictions, as compared to the Ni–Adams [Ni RG, Adams RD. The damping and dynamic moduli of symmetric laminated composite beams—theoretical and experimental results. J Compos Mater 1984;18(2):104–21] and Adams–Maheri [Adams RD, Maheri MR. Dynamic flexural properties of anisotropic fibrous composite beams. Compos Sci Technol 1994;50(4):497–514] models, generally demonstrate good agreements with the experimental data and the FEM results.

Secondary Torque in Automotive Drive Shaft Ball Joints: Influence of Geometry and Friction

Automotive drive shafts are made of two constant velocity joints coupled by an intermediate shaft. In general, the joint close to the gearbox is a plunging tripod joint, the movement of which serves suspension. The joint close to the wheel is a fixed ball type joint, which allows the steering movement. The article is devoted to secondary torque generated by the ball joint during torque transmission. This study is based on an ADAMS model in rigid bodies with local deformation at contact (Hertz theory) and on industrial test bench measurements. After geometrical representation of ball joint kinematics and before the secondary torque calculation, the ADAMS model is validated through the calculation of internal efforts, which are compared with the models and measurements already presented in the literature. Concerning the secondary torque study, measurements with an industrial test bench at the NTN TE Test Department and the ADAMS model show that the R6 component of the secondary torque (orthogonal to the joint plane) is found to be negligible with respect to the transmitted torque (<2 N m for 300 N m input torque). The results of the ADAMS model also show that the steering component of the secondary torque (in the joint plane and orthogonal to the wheel axis) does not only depend on the joint angle but also on the friction and sign of the transmitted power.

Simulation results for design and operation of CALUMA, a new low-cost humanoid robot

SUMMARYThis paper presents simulation results for basic operation of CALUMA (CAssino Low-cost hUMAnoid robot). The new humanoid robot CALUMA is described with its characteristics of low-cost design and easy-operation behavior. A CALUMA model in ADAMS environment has been elaborated. The CALUMA ADAMS model has been used for a dynamic simulation of robot operation. Three modes for the dynamic simulation have been studied, namely straight walking, walking with a grasped object in the hand, and lifting an object. The results of simulating those basic operations show the feasibility of the proposed design for CALUMA robot and validate its operation. Improvements have been illustrated in the design evolution for the robot structure and operation as suggested by simulation results.

Removal of copper(II) from aqueous phase by Purolite C100-MB cation exchange resin in fixed bed columns: Modeling

The dynamic removal of copper by Purolite C100-MB cation exchange resin was studied in packed bed columns. The values of column parameters are predicted as a function of flow rate and bed height. Batch experiments were performed using the Na-form resin to determine equilibrium and kinetics of copper removal. The uptake of Cu(II) by this resin follows first-order kinetics. The effect of stirring speed and temperature on the removal kinetics was studied. The activation energy for the exchange reaction is 13.58 kJ mol −1. The equilibrium data obtained in this study have been found to fit both the Langmuir and Freundlich isotherm equations. A series of column tests were performed to determine the breakthrough curves with varying bed heights and flow rates. To predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design, four kinetic models; Bohart–Adams, Bed Depth Service Time (BDST), Clark and Wolborska models are applied to experimental data. All models are found suitable for describing the whole or a definite part of the dynamic behavior of the column with respect to flow rate and bed height. The simulation of the whole breakthrough curve is effective with the Bohart–Adams and the Clark models, but the Bohart–Adams model is better. The breakthrough is best predicted by the Wolborska model. The breakthrough data gave a good fit to the BDST model, resulting in a bed exchange capacity very close to the value determined in the batch process.

Cyanobacterial biosorption of Cr(VI): Application of two parameter and Bohart Adams models for batch and column studies

Abstract The present investigation was aimed at analyzing the potential utility of Lyngbya putealis HH-15, an indigenous cyanobacterium isolated from a metal contaminated site as a biosorbent of Cr(VI) from aqueous solutions using static and dynamic mode studies. Surface adsorption of the metal at specific binding sites on the algal biosorbent was confirmed through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) spectral analysis. Kinetic model was applied to study the adsorption process. Intraparticle diffusion plot of the data indicated the involvement of both surface sorption and intraparticle diffusion. Six two-parameter equations (Langmuir, Freundlich, Temkin, Flory–Huggins, Dubinin–Radushkevich, D–R and Brunauer, Emmer and Teller, BET isotherms) were applied to model the equilibrium sorption data on both free and immobilized form of the cyanobacterial biosorbent. In continuous flow column experiments effects of bed height (5–10 cm), flow rate (1–3 mL/min), and initial metal ion concentration (5–20 mg/L) on breakthrough time and adsorption capacity of the immobilized biosorbent were studied. The data generated was developed into a model based on empirical relationship of the Bohart–Adams model. The column regeneration studies were also performed using 0.1 M HCl for five cycles. The high chromium removal ability and regeneration efficiency of this biosorbent suggest its applicability in industrial processes and data generated would help in further upscaling of the adsorption process.

Single and bulk compression of pharmaceutical excipients: Evaluation of mechanical properties

The compaction of powders into tablets is widely used in the pharmaceutical industry to convert drugs, in the form of small particles, into coherent and robust metered solid dosage forms. In order to produce robust tablets with the required properties, it is essential to understand the elastic, viscoelastic and plastic properties and rupture strength of the feed particles, which can be as small as a few microns in diameter. The objective of this work is to characterise the mechanical properties of single particles using a micromanipulation diametrical compression technique and relate the parameters to the compression behaviour of powders. Mechanical parameters, such as the Young's modulus, hardness and nominal rupture stress, were thus determined for each sample. The bulk compression data of the powders were analysed to calculate the parameters of the Heckel (Heckel, R.W., 1961a An analysis of powder compaction phenomena, Trans Metal Soc. AIME, 221, 1001–1008; Heckel, R.W., 1961b Density–pressure relationships in powder compaction, Trans Metal Soc. AIME 671–675), Kawakita (Kawakita, K. and Ludde, K.H., 1971 Some considerations on powder compression equations, Powder Technology, 4, 61–68) and Adams (Adams, M.J., Mullier, M.A. and Seville, J.P.K., 1994 Agglomerate strength measurement using a uniaxial confined compression test, Powder Technology, 78, 5–13.) models. These parameters will be compared with each other, and with the mechanical properties of the individual component particles. A correlation has been found between the nominal rupture stress of single particles and the apparent strength derived from the Kawakita and Adams models.

On the instantaneous formation of cavitation in hydrodynamic lubrication

We consider the Elrod–Adams model extending the classical lubrication Reynolds equation to the case of the possible presence of a cavitation region. We show that the behaviour of the pressure and saturation depends crucially on the behaviour of the separation h ( t , x , y ) among the two surfaces. In particular, we exhibit some simple formulations for which we prove (rigorously) that a cavitation region is formed instantaneously (even for initially saturated flows). Some numerical experiences are also given. To cite this article: J.I. Díaz, S. Martin, C. R. Mecanique 334 (2006).

Dye removal by low cost adsorbents: Hazelnut shells in comparison with wood sawdust

Batch adsorption of Methylene Blue, up to 1000 mg L −1, and Acid Blue 25, up to 500 mg L −1, onto ground hazelnut shells was studied in comparison with sawdust of various species of wood, in order to explore the potential use of this material as low cost adsorbent for dye removal in dyehouse effluents. The adsorption kinetics was investigated according to Lagergren's model, but the best fit was achieved by a second order equation. The equilibrium data were processed according to Langmuir's model and higher adsorption capacity values towards both dyes were shown by hazelnut shells than wood sawdust. Moreover, fixed bed adsorption of Methylene Blue was performed on hazelnut shell columns and the breakthrough curves were determined by varying bed depth, flow rate and influent concentration. The data were processed according to Bohart–Adams model and the column performances could be predicted by the bed depth service time (BDST) approach.

Effect of Blade Torsion on Modeling Results for the Small Wind Research Turbine (SWRT)

The small wind research turbine (SWRT) testing project was initiated with the goal of better characterizing both small wind turbine loads and dynamic behavior. The main purpose of the testing was to produce high quality data sets for model development and validation and to help the wind industry further their understanding of small wind turbine behavior, including furling. Previous papers have discussed modeling results for the SWRT using the FAST aeroelastic simulator. This paper summarizes modeling results from both the FAST and ADAMS aeroelastic simulators. The ADAMS model allows for blade torsional stiffness to be modeled, which is shown to significantly improve the agreement between model and test results for rotor speed and explain variances in previous comparisons between the SWRT FAST modeling results and the SWRT test data. The ADAMS model results also show that the aerodynamic pitching moment impacts the blade torsion more than the inertial forces.

Dynamic sorption of methylene blue by cedar sawdust and crushed brick in fixed bed columns

The dynamic removal of methylene blue by cedar sawdust and crushed brick was studied in packed bed columns. The values of column parameters were predicted as a function of flow rate and bed height. On evaluating the breakthrough curves, the sorption isotherms of methylene blue onto cedar sawdust and crushed brick in 20 °C aqueous solution were experimentally determined in batch conditions. Both the Freundlich and the Langmuir models were found to fit the sorption isotherm data well, but the Langmuir model was better. A series of column tests using cedar sawdust and crushed brick as low-cost sorbents were performed to determine the breakthrough curves with varying bed heights and flow rates. To predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design, five kinetic models; Bohart and Adams, bed depth service time (BDST), Clark, Wolborska, and Yoon and Nelson models were applied to experimental data. All models were found suitable for describing the whole or a definite part of the dynamic behavior of the column with respect to flow rate and bed height, with the exception of Bohart and Adams model. The simulation of the whole breakthrough curve was effective with the Yoon and Nelson and the Clark models, but the breakthrough was best predicted by the Wolborska model.

Gradient-based approximation methods applied to the optimal design of vehicle suspension systems using computational models with severe inherent noise

The principal aim of this paper is to evaluate the feasibility of using gradient-based approximation methods for the optimisation of the spring and damper characteristics of an off-road vehicle, for both ride comfort and handling. The Sequential Quadratic Programming algorithm and the relatively new Dynamic-Q method are the two successive approximation methods used for the optimisation. The determination of the objective function value is performed using computationally expensive numerical simulations that exhibit severe inherent numerical noise. The use of forward finite differences and central finite differences for the determination of the gradients of the objective function within Dynamic-Q is also investigated. This is done in investigating methods for overcoming the difficulties associated with the optimisation of noisy objective functions. A recreational off-road vehicle is modelled in ADAMS, and coupled to MATLAB for the execution of the optimisation process. The full vehicle ADAMS model includes suspension kinematics, a load-dependent tyre model, as well as non-linear springs and dampers. Up to four design variables are considered in modelling the suspension characteristics. It is found that both algorithms perform well in optimising handling. However, difficulties are encountered in obtaining improvements in the design process when ride comfort is considered. Nevertheless, meaningful design configurations are still achievable through the proposed optimisation process, at a relatively low cost in terms of the number of simulations that have to be performed.

Removal of lead(II) by adsorption using treated granular activated carbon: Batch and column studies

In the present study, a deeper understanding of adsorption behavior of Pb(II) from aqueous systems onto activated carbon and treated activated carbon has been attempted via static and column mode studies under various conditions. It probes mainly two adsorbents that is, activated carbon (AC) and modified activated carbon (AC–S). Characterization of both the adsorbents was one of the key focal areas of the present study. This has shown a clear change or demarcation in the various physical and chemical properties of the modified adsorbent from its precursor activated carbon. Both the adsorbents are subjected to static mode adsorption studies and then after a comparison based on isotherm analysis; more efficient adsorbent is screened for column mode adsorption studies. The lead removal increased for sample of treated carbon. The extent of Pb(II) removal was found to be higher in the treated activated carbon. The aim of carrying out the continuous-flow studies was to assess the effect of various process variables, viz., of bed height, hydraulic loading rate and initial feed concentration on breakthrough time and adsorption capacity. This has helped in ascertaining the practical applicability of the adsorbent. Breakthrough curves were plotted for the adsorption of lead on the adsorbent using continuous-flow column operation by varying different operating parameters like hydraulic loading rate (3.0–10.5 m 3/(h m 2)), bed height (0.3–0.5 m) and feed concentrations (2.0–6.0 mg/l). At the end, an attempt has also been made to model the data generated from column studies using the empirical relationship based on Bohart–Adams model. This model has provided an objective framework to the subjective interpretation of the adsorption system and the model constant obtained here can be used to achieve the ultimate objective of our study that is, up scaling and designing of adsorption process at the pilot plant scale level. AC–S column regeneration using 0.5 and 1.0 M concentration of HNO 3 has been investigated. It has shown a regeneration efficiency of 52.0% with 0.5 M HNO 3.

A Pilot Scale Evaluation for Adsorptive Removal of Lead (II) Using Treated Granular Activated Carbon

Wastewaters discharged from the defence serviceable industries pose a serious environmental hazard due to their heavy metal load. The present study focused on optimizing the operational variables viz, hydraulic loading rate, bed height and feed concentration through bench scale study and using that for assessing the efficiency of pilot scale system with sulphur loaded carbon (AC-S) as the adsorbent in the removal of Pb (II). Static mode adsorption studies were also carried out for Pb (II) removal using treated (AC-S) and untreated carbon (AC). AC-S shows about 35 percent increase in maximum adsorption capacity over that on AC. The maximum adsorption capacity in the column mode for Pb (II) at the optimized conditions: bed height of 0.4 m, hydraulic loading rate of 7.5 m3h−1m−2 and the feed concentration of 6 mg l−1 for achieving 50 % breakthrough concentration was found to be 2.89 mg g−1. Adsorption mechanism involved during Pb (II) in the column has also been explored. Bohart - Adams model was used for modeling the bench scale data and predicting the adsorption behavior at pilot scale level.

Effets d'anisotropie par homogénéisation dans un problème à frontière libre

The Elrod–Adams model is a pressure–saturation formulation which takes into account cavitation phenomena in thin fluid films mechanics. We study the asymptotic behavior of the model, using the two-scale convergence technique, in devices such as journal bearings. Interest is highly motivated by the roughness effects of the surfaces. Anisotropic effects appear on the coefficients, which is usual, but also on the saturation function, since various saturation functions appear through the homogenization process. To cite this article: G. Bayada et al., C. R. Acad. Sci. Paris, Ser. I 340 (2005).

In-series columns adsorption performance of Kraft mill wastewater pollutants onto volcanic soil

Two in-series columns systems with volcanic soil were tested for wastewater pollutants adsorption capacity. The first system was tested with acidified volcanic soil and the second with a reactivated volcanic soil. The reactivated soil was obtained by washing the previous spent acidified soil system with an acid solution. The systems parameters were obtained using the Bohardt and Adams model for fixed-beds. The acidified soil parameters indicated an adsorption capacity q of 28 and 139 mg/g of phenolic compounds and color, respectively (for each column), compared to 12 and 39 mg/g for the reactivated soil system. The adsorption rate constant k ranged between 1.5 × 10 −6 and 2.8 × 10 −6 l/min mg and no significant difference was observed for each analysed column system and pollutant. Furthermore, the molecular weight distribution analysis of input and output samples of one acidified soil column indicated that the fraction >30 000 Da is the most adsorbed until the breakpoint. Moreover, the CODs and tannins and lignin removal efficiencies at the breakpoint reached values between 60% and 70% in each column and each system, indicating that lower biodegradable compounds were retained effectively. The results indicate that it is possible to compare the acidified volcanic soil adsorption capacity with natural zeolites, and a preliminary costs evaluation indicates that volcanic soil could be also competitive, even when comparing with activated carbon.

Mercury (II) removal from water by coconut shell based activated carbon: Batch and column studies

This study was undertaken to investigate adsorption behavior of Hg (II) from aqueous systems on activated carbon in static and dynamic mode by varying initial Hg (II) concentration, adsorbent dose and pH. Langmuir and Freundlich adsorption isotherm were applied to model the adsorption data. Removal of mercury obeyed the Langmuir and Freundlich adsorption isotherm models. The extent of removal of Hg (II) was found to be dependent on sorbent dose, pH and initial Hg (II) concentration. Mercury uptake increased from 72 to 100 percent with increasing pH from 2 to 10. A set of desorption studies was also performed for the metal ions with the aim of investigating the mechanism involved. Moreover, the competing effects of various ions like Pb (II) and Cu (II) is also described. The column capacity for a column diameter of 20 mm, bed height of 0.4 m, hydraulic loading rate of 7.5 m3h‐1m‐2 and a feed concentration of 3 mg I‐1 were found to be 3.02 mg g‐1. Breakthrough curves were plotted for the adsorption of mercury on the adsorbent using continuous‐flow column operation by varying different operating parameters like hydraulic loading rate (3–10.5 m3h‐1m‐2), bed height (0.3–0.5 m), and feed concentrations (2–6 mg I‐1). The aim was to assess the effect of bed height, hydraulic loading rate and initial feed concentration on breakthrough time and adsorption capacity, which helped in ascertaining the practical applicability of the adsorbent. At the end an attempt has been made to develop empirical relationship from the data generated from column studies for designing the adsorption column, based on the Bohart ‐Adams model.

Sorption of anionic surfactants on a fixed bed of rubber granules

The performance of a fixed-bed adsorber (FBR) column for the removal of anionic surfactants from aquatic environments has been studied. Waste tyre rubber granules were used as the adsorbent material, and sodium dodecyl sulfate, an anionic surfactant, as the adsorbate. The FBR column design parameters were evaluated using the column breakthrough data at different bed depths. The Bohert and Adams model was used with the bed depth service time approach for the design of the column. The bed efficiency obtained was 90.97%.

An Efficient Multibody Dynamics Model for Internal Combustion Engine Systems

The equations of motion for the major components in an internalcombustion engine are developed herein using a recursive formulation.These components include the (rigid) engine block, pistons, connectingrods, (flexible) crankshaft, balance shafts, main bearings, and enginemounts. Relative coordinates are employed that automatically satisfy allconstraints and therefore lead to the minimum set of ordinarydifferential equations of motion. The derivation of the equations ofmotion is automated through the use of computer algebra as the precursorto automatically generating the computational (C or Fortran) subroutinesfor numerical integration. The entire automated procedure forms thebasis for an engine modeling template that may be used to supportthe up-front design of engines for noise and vibration targets.This procedure is demonstrated on an example engine under free(idealized) and firing conditions and the predicted engine responses arecompared with results from an ADAMS model. Results obtained by usingdifferent bearing models, including linear, nonlinear, and hydrodynamicbearing models, are discussed in detail.