The aim of this thesis was to design the steel frame and the supporting system for the air supported conveyor. Dimensions, drawings and calculations were wanted for the results.
This chapter describes the research problem and questions, the scope of the thesis and methods.
1.2.1 Research problem and questions
Based on the situation that the company did not have any experience about the design, the analysis of strength or manufacturing of the air supported conveyor, the knowledge and the research were required to complete the project. The research problem of the project can be said: “how to design the air supported conveyor and the cable stayed supporting system to be strength enough for the affecting loadings?”
The research questions are related to the strength of the conveyor and supporting system. It was known at the beginning of the project, that the conveyor and supports are forming a system, where loadings are influencing, which raised the questions. The following research questions were made:
How the conveyor and supporting system are related to each other in the design of the system?
What aspects are influencing loading versus strength capacity of the frame?
1.2.2 Scope and limitations of the thesis
The scope of this thesis included the design of the belt conveyor, design of the frame and design of the cable stayed supporting system. The design of the belt conveyor was included in the thesis that the wanted capacity could be achieved. The design of the frame and supporting system was conducted with the static loadings. Dynamic loadings were not in the scope of this thesis, thus the fatigue strength was not studied. In the cable stayed system, only the pylon construction including truss structure and cables were designed. The supporting structures under the pylon and the conveyor were not in the scope. Instead, the joints of the cables in the pylon and frame were included in the scope. The calculation of the air flow, pressure and design of the fan system for the conveyor were not included in the scope. Either thermal or vibration analysis were not included in the scope.
1.2.3 Methods
Methods included design, literature review, calculations and FE-analysis. The systematic design procedure was used to develop the final solution for the frame from the drafts.
Literature review was used to clear the manufacturing of the constructions. Belt conveyor design was used to ensure that the conveyor can convey the wanted capacity. Calculations of the strength and FE-analysis were used to ensure the strength of the design. In conclusion, following procedures were used to complete the project:
Systematic design procedure
Literature review
Design of belt conveyor
Calculations of strength
FE-analysis.
Calculation of strength included many subtopics, for example welding, design of connections and design of structural members. The subjects are separated for own sections in the thesis. Also, the determination of loads can be assumed to include for the calculation of strengths.
2 DESIGN OF CONVEYOR AND SUPPORTING SYSTEM
The concept of design means developing an idea in a form that actual application from it can be created and it is extensively used in the engineering field (Mital et al. 2008, p. 37). Other definitions from design can also be made depending on the perspective it is treated. Phal et al. (2007, p. 2) described the term of design in the systematic way: “designing is the optimization of given objectives within partly conflicting constraints.” From the view point of a product, the design is a stage of a life cycle and it is usually categorized to the same stage as a product development. The life cycle of the product starts from the product planning and the design stages, together these two stages have a major impact on the profit of the product. (Breiing, Engelmann & Gutwoski 2009, p. 820–821.) Figure 8 presents the life cycle of a product by means of time and the turnover from the product and how the design phase is placed in the life cycle.
Figure 8. Economic life cycle of a product (mod. Pahl et al. 2007, 65).
The engineering design can be done by using a design process which is a step by step proceeding approach. The design process is based on individual tasks or stages which are done in sequential order. Usually the design process has an iterative nature and step back to
the previous stage can be done if the evaluation pointed out some weaknesses. Many design methods have been developed for different purposes and even individual designer can have its own design practices. In the figure 9 is presented a simple design procedure with steps and iterations. (Childs 2014, p. 4–5.)
Figure 9. Conventional design procedure (Childs 2014, p. 4).
Systematic design process is a one approach to the product design and development. The Systematic design procedure is implemented in four stages: product planning and clarifying the task, conceptual design, embodiment design and detail design. The systematic design approach is a suitable method especially for the product design of mechanical engineering applications because it is solidly constructed to consider the demands of technical aspects in all design steps. The procedure is helpful in planning, decision making and forming a solution from the design problem. Figure 10 presents the systematic design procedure. (Pahl et al. 2007, 128–129.)
Figure 10. Systematic design procedure presented as individual stages (Pahl et al. 2007, p.
130).