3D Dynamical Model For Liquid Sloshing Simulation In A Partially Filled Elliptical Tank

Many of 2D mechanical models have been devel-oped to simulate liquid sloshing of a partially filled tank with different shapes. However, those models didn’t represent properly the complex liquid motion, especially in the case of portable tanks. Indeed, forces exerted on the liquid can be lat-eral, longitudinal and vertical. Then, liquid displacement and pressure forces applied to the tank walls are undervalued and may cause design flaws. In this case, 2D mechanical models are ineffective for liquid motion simulation. In previous studies, a 3D equivalent mechanical model has been developed. This dy-namical model is used to simulate different liquid motion in a partially filled tank that consider any sort of excitement forces and get more accurate results in terms of displacements and pressure forces. In this study, a brief description of the new dy-namical model is given, including the liquid discretization pro-cess, stiffness and damping coefficients computing method and equations of motion. Afterward, the model is applied to an el-liptical cross section tank to obtain displacement and pressure forces of the liquid. Finally, the results are compared to the lit-erature

Fatigue cycles and performance evaluation of accelerating aging heat treated aluminum semi solid materials designed for automotive dynamic components

The A357-type (Al-Si-Mg) aluminum semi solid casting materials are known for their excellent strength and good ductility, which make them materials of choice, preferable in the manufacturing of automotive dynamic mechanical components. Semi-solid casting is considered as an effective technique for the manufacturing of automotive mechanical dynamic components of superior quality performance and efficiency. The lower control arm in an automotive suspension system is the significant mechanical dynamic component responsible for linking the wheels of the vehicle to the chassis. A new trend is to manufacture this part from A357 aluminum alloy due to its lightweight, high specific strength, and better corrosion resistance than steel. This study proposes different designs of a suspension control arm developed, concerning its strength to weight ratio. Furthermore, this study aims to investigate the effect of accelerating thermal aging treatments on the fatigue life of bending fatigue specimens manufactured from alloy A357 using the Rheocasting semi-solid technology. The results revealed that the multiple aging cycles, of WC3, indicated superior fatigue life compared to standard thermal aging cycles. On the other hand, the proposed designs of automotive suspension control components showed higher strength-to-weight ratios, better stress distribution, and lower Von-Mises stresses compared to conventional designs

Effect of Rainflow Cycle Number on Fatigue Lifetime of an Arm of a Vehicle Suspension System

Fatigue is considered as one of the main cause ofmechanical properties degradation of mechanical parts.Reliabilities methods are appropriate for fatigue analysis usinguncertainties that exist in fatigue material or process parameters.Current work aims the study of the effect of the Rainflow cyclenumber on fatigue lifetime of an upper arm of the vehiclesuspension system. The major part of the fatigue damage inducedin suspension arm is caused by two main classes of parameters.First parameter characterizes materials properties and a secondone describes equivalent force generated by road excitation andpassenger’s number. Therefore, representative sampling ofYoung's modulus and equivalent loading are selected as inputparameters to conduct repetitive finite elements simulations byMonte Carlo (MC) algorithm. Strain-life approach based onManson-coffin and Ramberg-Osgood equations is used in orderto determine fatigue lifetime of each combination of inputparameters. Thereafter, response surface is built according topreselected performance function. A PYTHON script wasdeveloped to automatize finite element simulations of the upperarm according to a design of experiments. Preliminary resultsshow Rainflow primary cycles to have significant effect onobtained cycle’s number to fracture. Load generated byexcitation road have a remarkable quasi-linear inverselyproportional effect on fatigue lifetime

Quality index charts of Al-Si-Mg semi solid alloys subjected to multiple temperatures aging treatments and different quenching media

The use of quality index charts is considered as an effective mean for evaluating the mechanical performance of Aluminum alloys for industrial engineering applications. The current study was carried out to investigate the influences of multiple-interrupted temperatures aging and quenching media (water versus air) on the quality index performance and precipitations evolution of A357 Aluminum semi solid alloys. Regarding the lack of similar investigations applied on such alloys, the quality index charts were generated for Al-Si-Mg semi solid castings based on its tensile properties. These charts are used to determine the quality index, in MPa, as a simple mean for compromising the strength and ductility together in one value using the Drouzy model. The multiple temperatures aging cycles were applied to improve the quality index values of Al-Si-Mg semi solid alloys for enhancing its characteristic and performance to resist the mechanical failures relating to automotive dynamic parts. The evolution of Mg2Si hardening precipitates, formed for specific thermal aging cycles, was investigated using transmission electron microscopy (TEM). The results obtained in this work revealed that the optimum quality index values were obtained by the application of T6-thermal under-aging treatment cycles. The regression models, using a statistical design of experiments, indicated that the optimum strength and high-quality index values were obtained by the application of interrupted thermal aging cycles, mainly C2,3-T6/T4/T7 conditions

Evaluation of mechanical properties and durability performance of HDPE-wood composites

The objective of this work is to evaluate the mechanical properties and durability performance of bio-composite materials made from sawdust and thermoplastic polymer (HDPE). For the preparation of the composites, sawdust in different proportions with Maleic Anhydride grafted Polyethylene (MAPE) as the coupling agent was used. The thermal and mechanical properties were successively characterized. The results indicate that adding wood fillers to a polymer matrix increases the degree of crystallinity and improves the tensile strength and ductility of composites. On the contrary, resistance to water absorption decreases as a function of the wood fillers. Scanning electron microscopy (SEM) was used to analyze morphological structure alteration when exposed to intense weathering. The biodegradability of bio-composites up to 97 days was also investigated; the results indicate that, by increasing the filler content, the amount of weight loss increased as well. In other words, even though the addition of sawdust to thermoplastic polymer improves the mechanical performance of a composite material, it also accelerates the biodegradation rate of the composite. An optimum amount of filler content might compromise the effect of biodegradation and mechanical properties of composite materials

Development of an analytical dynamic model of a vibro‐compactor used in carbon anode production

The carbon anode quality has a significant impact on the production of primary aluminum. Their performance can be evaluated by their various mechanical, electrical, physical, and chemical, properties such as density, electric resistivity, C02 and air reactivities. The focus of this work is to study the various parameters of the vibro-compaction, which is one of the critical steps in the process of anode manufacturing. In this work, a dynamic model of a vibro-compactor is developed. The vibrocompactor is modeled as a rigid mass suspended on springs and dampers and subjected to harmonic external excitation. This model is used to identify the optimal conditions of the vibrocompacting process. These conditions are obtained through a correlation between the analytical vibro-compaction parameters and data from an industrial vibro-compactor. The use of optimum parameters will help improve the anode performance and, consequently, lead to better productivity and reduction on environmental impact

Evolution of anode properties during baking

Carbon anodes are used in electrolytic production of aluminum. Good quality anodes decrease carbon and energy consumption, greenhouse gas emissions, and increase anode production as well as anode life. Many factors such as quality of raw materials, anode recipe and operational parameters of different units (mixing, compacting and baking) affect anode properties, consequently, anode quality. One of the important anode properties is density. High density anodes have longer life and they have to be changed less often during the electrolysis. Too low or too high density is the indication of the presence of cracks and pores which increase the electrical resistivity, thus, energy required to produce the anodes. In this work, the evolution of anode structure (development of pores/cracks), consequently, anode properties (density, electrical resistivity) during baking was studied by stopping the anode baking at the intermediate temperatures and measuring the anode properties. In addition, an apparatus was developed for continuously monitoring the development of anode electrical resistivity during anode baking. This knowledge can be helpful for improving the anode quality

Characterization of cracking mechanisms of carbon anodes used in aluminum industry by optical microscopy and tomography

The objective of this work is to understand the different mechanisms of crack formation in dense anodes used in the aluminum industry. The first approach used is based on the qualitative characterization of the surface cracks and the depth of these cracks. The second approach, which constitutes a quantitative characterization, is carried out by determining the distribution of the crack width along its length as well as the percentage of the surface containing cracks. A qualitative analysis of crack formation was also carried out using 3D tomography. It was observed that mixing and forming conditions have a significant effect on crack formation in green anodes. The devolatilization of pitch during baking causes the formation and propagation of cracks in baked anodes in which large particles control the direction of crack propagation

The Influence of Tractor-Seat Height above the Ground on Lateral Vibrations

Farmers experience whole-body vibrations when they drive tractors. Among the various factors that influence the vibrations to which the driver is exposed are terrain roughness, tractor speed, tire type and pressure, rear axle width, and tractor seat height above the ground. In this paper the influence of tractor seat height above the ground on the lateral vibrations to which the tractor driver is exposed is studied by means of a geometrical and an experimental analysis. Both analyses show that: (i) lateral vibrations experienced by a tractor driver increase linearly with tractor-seat height above the ground; (ii) lateral vibrations to which the tractor driver is exposed can equal or exceed vertical vibrations; (iii) in medium-size tractors, a feasible 30 cm reduction in the height of the tractor seat, which represents only 15% of its current height, will reduce the lateral vibrations by around 20%; and (iv) vertical vibrations are scarcely influenced by tractor-seat height above the ground. The results suggest that manufacturers could increase the comfort of tractors by lowering tractor-seat height above the ground, which will reduce lateral vibrations

Numerical investigation of the load free permanent strain in carbon anode during baking process

Baking is the final step of the anode production, which plays a major role in attaining the anode properties required by industry. However, the anode baking is a costly process during which various complex phenomena take place. It is therefore important to ensure good understanding of the impact of these phenomena on the baked anode quality. Regarding the mechanical aspect, various strain mechanisms occur in the anodes during the baking and evolve with respect to the spatial distribution of temperature and its rate of change in the baking furnace. Each of these mechanisms contributes to the stress equilibrium in the carbon anode and can lead, depending on the baking conditions, to poor mechanical properties including cracks when the failure limit is exceeded. In this paper, a specialized thermo-reactive visco-elastoplastic model is presented, which allow the numerical investigation of the stress distribution in the anode during baking. Each strain mechanism considered in the model is presented with a particular attention given to the permanent and non-recoverable strain mechanism occurring before the initial volatile release phase. Finally, the definition of a baking index is discussed to ensure the best approach to be used to quantify the evolution of anode properties during baking