Customers all over the world have great expectations in terms of the delivery and availability of supplied items. It is thought that the most important, both for suppliers and their customers, are ...short-term orders realisation and flexible services. Simulation methods can be a strongly support for an entrepreneur in decision making process connected to these expectations or short-period and long-period planning. Simulation methods ensure possibilities to test and analyse different kind of “what-if” scenarios of distribution systems such as: potential surplus of orders or other untypical things mostly describes as force majeure. The main aim of the paper is to consider simulation model of distribution system that occur in one international entrepreneur that operates in the area of Poland. The paper consists of literature review, a reference model of the original system with elementary formal notation included and a reference model implementation into simulation software (in form of simulation model), conclusions and potential directions on the model development. The model of the distribution system consists of vertices and edges. Chosen vertices are elementary form of logistics facilities such as warehouses and production facilities such as factories. Meanwhile, edges are real shaped routes between verticals, if they exist.
In this paper a simulation model of a part of logistics facility, i.e. an order picking area in a high-bay warehouse, is considered. The construction of this model was preceded by the development of ...a conceptual model as a result of the study for selected warehouses of this type. The researched simulation model is not a reflection of a logistics facility functioning in reality. This facility is a hypothetical warehouse. The simulation model includes generators of pseudorandom numbers, which, among other things, serve to obtain and introduce randomly generated picking orders (picking lists) into the model. And at the same time these generators reflect and provide the real, often unforeseen, size of orders. This allows, among other things, to analyze the capacity of the considered facility. The paper presents a comparison of results obtained with use of simulation model for pseudorandom number generator with different data at the input to these model.
The shuttle-carrier warehouse is a new kind of high-density intelligent high-bay warehouse. Based on existing research, the storage allocation problem of this intelligent highbay warehouse has been ...studied, and an improved dynamic programming algorithm has been proposed based on the idea of route selection. The objective function designed in this paper mainly considers the "task completion time" and the "device busy level variance" for the multiple pallets of multiple tasks which will be allocated into the warehouse. The "task completion time" allows the algorithm to allocate the storage locations according to the current state of the warehouse and the optimized route, thus reducing the time to complete all tasks. A smaller "device busy level variance" allows the workload of the device to be well balanced, avoiding some devices being too busy and causing excessive devices' loss or rapid power consumption. Through simulation experiments, the improved algorithm reduces the "task completion time" by 36.5% and the average "device busy level variance" by 14.5% compared to the unimproved algorithm.
The transport plays a growing role in the integrated logistics management of semi-finished products and components flow. For manufacturing companies it is important to maximize the use of production ...resources, minimize the number of transport resources and optimize the process, in terms of both production costs and time. The use of specific means of transport and correct organization of material flow are fundamental in order to assure continuity of production and to deliver products to the customer just in time. Due to highly complicated processes of organization and management of material flow, computer systems are currently used. Based on this type of application, some necessary simulations were carried out. These tests were aimed at investigating the impact of the number of transport resources on handling time of high-bay warehouse. On this basis, a methodology of defining a multi-objective function and determining weights of each objective are presented. The conducted analysis allowed to select the most effective number of internal transport resources in exemplary warehouse. The obtained results, particular stages of conducted analysis and conclusions were presented in this paper.
Bei automatisierten Hochregallagern werden sehr strenge Anforderungen an die Verformung der Bodenplatte gestellt, die zu weitgehend fugenlosen Konstruktionen führen. Stahlfasern können hier auf ...Grundlage der DAfStb‐Richtlinie „Stahlfaserbeton” für den Nachweis der notwendigen Rissbreitenbegrenzung angerechnet werden. Weiterhin ergeben sich in der Regel sehr hohe Lasten durch die Regalstützen auf der Bodenplatte und bei Bauvorhaben in Silobauweise müssen zudem Lasten aus der Dachkonstruktion berücksichtigt werden. Die Anrechnung der Stahlfaserwirkung beim Durchstanznachweis kann hilfreich sein, um die Plattendicke zu reduzieren, soweit dies die Verformungsanforderungen zulassen, oder auf aufwendige Durchstanzbewehrung zu verzichten. Anhand eines Praxisbeispiels wird verdeutlicht, dass eine Kombination von Stahlfasern und herkömmlicher Betonstahlbewehrung wirtschaftlich sein kann und auf welche Details im Sinne der Ausführung geachtet werden muss.
Use of steel fibre reinforced concrete in floor slab for automated high‐bay warehouses
In automated high‐bay warehouses, very strict requirements are placed on the deformation of the floor slab, which lead to largely jointless constructions. Steel fibres can be used here on the basis of the DAfStb guideline ”Steel fibre concrete“ for the verification of the necessary crack width limitation. Furthermore, there are usually very high loads on the floor slab from the racking supports, and in the case of clad rack construction loads from the roof structure must also be taken into account. The inclusion of steel fibres in the punching shear check can help to reduce the slab thickness, as far as the deformation requirements allow, or to do without costly punching shear reinforcement. By means of a practical example, it is shown that a combination of steel fibres and conventional reinforcing steel can be economical. Furthermore, it is explained by way of example which details must be taken into account in terms of execution.
Considering that the determination of fire hazard zones in warehouses is not sufficiently researched and studied, this paper aims to present a new methodological approach concerning the mentioned ...issue. Based on the COPRAS multi-criteria decision-making method, a new method was developed for the precise determination of potential zones where there is a risk of fire. The advantage of the described method is that it allows the quick and easy determination of all-orientation fire risk zones. The method requires fewer hardware resources compared to the existing ones and enables the display of the warehouse space in the form of a 3D model with calculated fire hazard zones. The mentioned procedure represents the first step when planning the layout and arrangement in the warehouse itself. The effectiveness of the proposed method was confirmed through a suitable numerical example.
Fully automated electrically powered stacker cranes are the most common transportation devices used in automated high bay warehouses. When high throughputs are attained, the amount of the electric ...energy used is high. Taking this into account, together with relatively high rack configuration the energy saving by employing the regeneration of potential energy during the lowering of the stored goods seems to be a promising choice. In the paper real life data for deployment of four stacker cranes in high bay warehouse of bigger dairy is introduced and analysed. The cranes’ working cycles are determined and their energy consumption is estimated. Finally, the probable energy and costs savings are determined taking into account the regenerated energy for crane operations and lower energy consumption for refrigeration purposes.
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