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This paper aims to introduce, apply and validate, through a realistic case study, an analytical cost model to support the design of the tow-train feeding system for mixed-model assembly lines managed according to the just-in-time concept. The fleet size and inventory level, minimizing the total annual cost, are the key model goals, while the tow-train shipping capacity and the service level are the decisional variables to set.

The model computes the material handling, inventory and stockout rising costs of the tow-train feeding system and looks for their minimization. It further computes the expected lead time between consecutive round-trips and the Kanban card number, distinguishing among parts and assembly lines, overcoming the simplifying hypothesis assuming a constant lead time for all parts. The model is validated against a dedicated case study stressing its strengths in terms of cost and inventory-level reduction.

The proposed approach is found to be effective if compared to the standard literature in the field of Kanban system design. The 10.76 per cent cost saving is experienced for the considered case study, and the inventory level is closer to the field-experienced profile.

The model adopts a practical perspective, making it easy and applicable to common operative industries.

The literature neglects to consider the differences in the part consumption when estimating the lead time between tow-train round-trips. The proposed model overcomes such limitations and strengthens the model applicability and performances.

The purpose of this paper is to present an analytical modelling approach to predict engineering elastic constants of 3D woven orthogonal composites (3DWOCs) at representative volume element (RVE) level using a volume averaging method.

The present analytical modeling approach uses a more realistic internal geometry representation of the 3DWOC. A RVE which is a repeating element at macroscopic level is first identified and volume proportions and engineering elastic constants of various constituents (matrix and family of constituent tows; warp, weft and z‐fibers) which contribute to the global stiffness of RVE/composite are next determined. For accurate predictions, emphasis is given to accurate measurements of micro‐structural data such as fiber volume fraction and fiber volume proportion of constituent tows and internal geometry of the 3DWOC structure‐in particular, undulation of z‐fibers. Microscopic study has been conducted in this regard.

The predicted engineering elastic constants are compared against experimental data, showing a strong correlation between predicted and experimental values.

The methodology presented in the paper can be used for accurate computation of the engineering elastic constants of 3DWOCs. The method can also be used for other types of 2D or 3D textile composites such as 2D woven composites, 2D braided composites, 3D woven angle interlock composites and 3D braided composites.

The paper succeeds in relating the micro‐structural properties and analytical model for the accurate prediction of engineering elastic constants.

This paper aims to investigate the scheduling and loading problems of tow trains for mixed-model assembly lines (MMALs). An in-plant milk-run delivery model has been formulated to minimize total line-side inventory for all stations over the planning horizon by specifying the departure time, parts quantity of each delivery and the destination station.

An immune clonal selection algorithm (ICSA) combined with neighborhood search (NS) and simulated annealing (SA) operators, which is called the NSICSA algorithm, is developed, possessing the global search ability of ICSA, the ability of SA for escaping local optimum and the deep search ability of NS to get better solutions.

The modifications have overcome the deficiency of insufficient local search and deepened the search depth of the original metaheuristic. Meanwhile, good approximate solutions are obtained in small-, medium- and large-scale instances. Furthermore, inventory peaks are in control according to computational results, proving the effectiveness of the mathematical model.

This study works out only if there is no breakdown of tow trains. The current work contributes to the in-plant milk-run delivery scheduling for MMALs, and it can be modified to deal with similar part feeding problems.

The capacity limit of line-side inventory for workstations as well as no stock-outs rules are taken into account, and the scheduling and loading problems are solved satisfactorily for the part distribution of MMALs.

In this paper, continuous glass tow preg-reinforced acrylonitrile butadiene styrene (ABS) composites were fabricated by using a 3D printing method, and the purpose of this study is the investigation of the fiber preimpregnation effect on the mechanical behavior of these composites. In addition, a simple theoretical approach (mixture law), which considers the elastic behavior of reinforced composites and a numerical simulation method based on finite element method (FEM), was used to predict the tensile stress–strain behavior of ABS/glass tow preg composites in the elastic region.

Different groups of preimpregnated glass tows with various ABS amounts (named 2%, 10%, 20% and 30%) were prepared by the solution impregnation method. Then, preimpregnated glass tows (prepregs or tow-pregs) were fed into the printer head along with the polymeric ABS filament to print the composites. The tensile, flexural and short beam tests were conducted to evaluate the mechanical properties of the printed composites.

The first result of using tow-pregs instead of dry tows in continuous fiber 3D printing is much easier printing, printability improvement and the possibility of printing layers with low thickness, which can further increase the mechanical properties. The mechanical test results showed all of the glass prepregs improve strength and modulus in the tensile, three-point bending and short beam tests compared with neat ABS specimens, but statistical analysis showed that ABS weight percentage in the prepregs had no significant effect on the mechanical strength of composites except for the tensile modulus. Samples containing 2%-prepreg (minimum ABS amount in the tow-pregs) showed a significant improvement in tensile modulus. In the simulation section, good agreement is obtained between the model predictions and experimental tensile results. The results show that an acceptable deviation (14%) exists between the experimental and predicted value of elastic modulus by the numerical model.

To the best of the authors’ knowledge, this is the first study showing the effects of ABS weight percentage in prepregs on the mechanical properties of 3D printed continuous fiber-reinforced composites and predicting the mechanical behavior of 3D printed composites by numerical simulation method.

A SURVEY of the information available regarding the application of the results of tests of models in towing basins to the design of floats for seaplanes was made by the National Advisory Committee lor Aeronautics in 1929. It was found that the development of flying boats and seaplanes had been assisted very much in the United States, and possibly more in other countries, by tests of models in towing basins or tanks (References 1 and 2). Some tanks already existed which were designed especially for testing models of seaplane floats and the construction of other tanks for this special purpose was projected (References 3 and 4). There was no such tank in the United States; in fact, there were only two tanks, both constructed before the appearance of the seaplane and designed originally to test models of ships. The construction in the United States of a special towing basin that could be devoted to tests of models of seaplane floats and hulls might reasonably be expected to be of great assistance in the further development of this type of aircraft, the importance of which appeared to be increasing.

The purpose of this paper is to examine and model the in-plant operational efficiency of tow trucks of an automobile manufacturing plant. Even though, tow trucks contribute toward the improvement of operational performance, little case-based evidence prevail in the literature. For this purpose, a case study has been conducted in an Indian automobile manufacturer to address the prevailing issues in material handling (MH).

Initially, this paper focuses on grouping of the sequence parts and finding the shortest path among the groups. To elucidate this, an analytical framework based on the distance and stuffing quantity is proposed. A fuzzy Dijkstra’s algorithm is used to solve the issues in grouping of the sequence parts and shortest path among the groups.

This study addressed the four aspects of MH: move cost, time, distance and material by integrating the function of grouping, finding the shortest path and communication with low cost devices. The result shows that logistics routes and activities should not be interrupted by any of the external factors. The availability of stock is a key performance variable to attain efficiency. In addition to this, effective communication between the truck operators and the production line managers is key performance indicator.

The paper helps the automobile practitioners on increasing the efficiency of tow truck by systemizing the routes. Logistics routes and activities should not be interrupted by any of the external factors. The availability of stock is a key performance variable to attain efficiency. In addition to this, effective communication between the truck operators and the line managers is key performance indicator.

Goldhofer Fahrzeugwerk GmbH & Co. just received its first order for a towbarless aircraft towing tractor, type AST 1. The order has been placed by SWISSAIR, which intends to operate the tow tractor at the Zürich airport after its delivery in July 1991. The delivery scope amounts to approx. DM 2M. It is expected that SWISSAIR will meet its further demand for aircraft tow tractors in the coming years by the latest Goldhofer technology. Two vehicle sizes (AST 1: 100 t — 450 t take‐off weight and AST 2:40t — 180t take‐off weight) cover most internationally used aircraft models.

Organisations operate within a three‐tiered environment – internal, micro and macro. The environment is a powerjul force acting upon the effectiveness of strategic decision making. Failure to take cognisance of the influence of the three‐tiered environment can have disastrous consequences. The cross‐impact matrix and the TOWS matrix are two strategic decision‐making aids that improve effective decision making. When used in conjunction with creative problem solving methods they can provide the basis of a powerful management tool.

A strength testing method formerly used in Germany is described. Aircraft components were towed under water in a large tank so that loads were produced on the specimen equivalent to those realized under actual flight conditions. Advantages of the method were that no special means for transmitting forces to the specimen were needed and that all changes of the air loads resulting from elastic deformation were automatically included in the applied loading. Particulars arc given about tests made on cabin hoods, tail planes and on one wing. Future possibilities of testing whole aircraft and of conducting research into the effects of clastic deformations on stabilitity characteristics are discussed. The limitations of the method arc given, especially with regard to the absence of compressibility effects. The opinion is advanced that despite these limitations further development of such testing methods should be considered.