Boom crane design and analysis with finite element method

Cranes are the machines that have duties at heavy industry, ship ports, shipyards and warehouses, these machines can lift and carry goods. Most remarkable crane types are bridge crane, portal crane, boom crane and mobile crane and these crane types take important place in machine industry. From perspective of safety, importance of crane design arise. Under various loads and hard working conditions of crane must be considered firstly in design step. When designing crane, various loads that effects crane should be considered. These loads are mainly, weight of goods that will be carried, crane self weight, dynamic loads that rised from motion, wind loads and these loads should be considered to make proper crane design. Force and moment effects are important at the design stage however these loads are not enough for satisfactory crane design. In addition to these loads, vibrational effects are also should be considered and analyses should be made. Making analyses in short terms with optimal design result is the goal to achieve with "Finite Element Method". In this thesis work, boom crane design is made, designed crane will be capable of carry and lift loads, goods at ship ports and shipyards. Crane that is designed with the capacity of 60 m x 50 tonne, can move on the rails with aid of boom part that is connected to platform, can lift and carry various goods and loads. Firstly,crane definition and crane types have explained and general informations have given in the thesis. Afterwards, crane geometric model has designed, model is reached to its last design condition after repeated design steps. Parts that form geometric model assembly has explained and concerns that are related to design has given. CATIA software used in forming geometric model of crane. This CAD software is a good tool for CAD modelling and also output of design could easily imported by various simulation packages. In the following sections, crane classification has made according to FEM and DIN standarts and analytical calculations has made which are related with crane design. Analytical calculations in design of crane are consist of crane equilibrium calculation, crane parts sizing, choosen motor power calculations and lifting ropes selection calculations. FEM and DIN standarts give information about using coefficients in design step. Also, some design related graphics and schematics given in these standarts. These coefficients, graphics and schematics that are related with crane classification is explained and used especially in analytical calculations. By obtained results of analytical calculations, design of crane adjusted for optimal design. "Finite Element Method" results are validated with Rayleigh-Ritz, Rayleigh methods and with Euler Bernoulli beam theory. Theoritically, these methods explained with derivations and principles they rely on. Rayleigh-Ritz method procedures give deflection of beams, Rayleigh method gives first natural frequency of beam without complex mathematical operations. Euler-Bernoulli beam theory is helpful when finding stress values. In the following chapter, some information about "Finite Element Method" software ANSYS has given. ANSYS software application fields and modular structure of the software explained. Following section of this chapter is focused on simple beam solution with "Finite Element Method" and solution validated with Euler-Bernoulli theory. Simple model solution steps showed in detail and results indicate validation of simulation with theory. At chapter seven, boom which is made of different cross sectioned parts solved with Rayleigh-Ritz method for deflection. By using MATLAB software, matlab code for solving Rayleigh-Ritz beam problems have written. MATLAB software is good tool for computing mathematical problems. It is used for solving validation problems in short terms while it is a big advantage in design process. Also, using computing software is valuable for making calculations more easily. Codes are given in Appendix of the thesis. Two main loading condition has considered in Rayleigh-Ritz method analyses. These are self weight analysis of boom part and analysis of boom when effected with various loads. Boundary conditions and loading conditions are defined and solved with given procedures with help of MATLAB codes. Following sections are crane finite element solutions of loading cases that are told previously. Also, boundary condition for vento rope is applied to the structure and results are found with small deviation to previous ones and this shows that both boundary conditions could be used for analysis. Last part of this chapter ends with portal assembly stress and total deformation analyses of the crane with boundary conditions and loading case by using "Finite Element Method" software package. Good mesh structure formed for the assembly analyses and boundary conditions with loads carefully entered to software. Results are obtained and showed that parts designed are suitable for strength point of view. Result are validated with Rayleigh-Ritz method , Rayleigh method and with help of Euler-Bernoulli beam theory. Safe and good optimization of structure achieved with using these analysis methods and "Finite Element Method". At chapter eight, vibration analyses took place and structural vibration effects are investigated. Modal analysis with "Finite Element Method" validation has made with Rayleigh method. First natural frequency of boom part is achieved without complex operations using Rayleigh method. First twelve mod shapes with natural frequencies solved with "Finite Element Method" modal analysis. Rayleigh method result didnt showed too much deviation from "Finite Element Method" modal analysis result. After this section, harmonic analysis has made with ANSYS and "Frequency Response Function" results are obtained. "Frequency Response Function" results shows that first mode which is first bending mode is important and gives relatively bigger amplitude than other modes. In modal analysis mesh structure also formed and boundary conditions applied with setting maximum modes to find property and analysis solved. In harmonic analysis, modal analysis setup is used and with defining harmonic force and by setting frequency range, analysis prepared for solving. Following solutions of two analysis, results obtained for vibrational analysis of the structure. At last chapter, results showed and discussed. Boom part solution plots which are Rayleigh-Ritz solution and "Finite Element Method" solution are given. From plots it is seen that deviation from Rayleigh-Ritz method solution to "Finite Element Solution" is at acceptable values. All results are given in a table and also close deviation values from both loading condition shows the consistency of the analyses. It is seen that Self weight loading contion show better approximation. For vibration analyses, deviation from computed first natural frequency to "Finite Element Method" is not a higher value. Natural frequency of other modes could be obtained in the future works with use of Rayleigh-Ritz method and also deviations from frequency results will be reduced. Harmonic analysis results show 0-20 Hz vibrational effects are also concluded and discussed in this chapter. Mod shapes consist of bending modes, which are for horizontal and vertical bending, torsional mode and elongation mode. It is seen that most dominant modes are for bending. As demonstrated, "Finite Element Method" and other methods for validation of the simulation, result deviations are in expected range so we can say that "Finite Element Method" results are consistent. Methods for using validation of structure also gives inner understanding of the system. Also, good approximations of methods for validation shows that these methods are valuable for design steps. Changes and actions taken that made for optimal design results are discussed and works done about this subject explained. Thesis results and datas showed that "Finite Element Method" is a efficient, reliable tool for structural analysis of systems such as crane systems. Also, making fast optimization of design steps is another advantage of using "Finite Element Method". However "Finite Element Method" results should be validated for consistency of analyses. In this thesis, Rayleigh-Ritz, Rayleigh and with help of Euler-Bernoulli theory explained and problems solved with these methods. Approximation of the solutions show that methods are good tools for validation and can be used with "Finite Element Method". Crane design thesis work revealed that using simulation based design with validation gives good results. For safety of the design, some aspects should be considered. Standarts about system regulations are also important should be carefully inspected. Use of simulations took important place however some analytical calculations also still remain important because of this aspect strength, materials knowledge, mechanical theories and other design related knowledge is very valuable. In heavy industry these systems will be improved and optimum results will be obtained. In future works, crane design will be improved and valuable design informations will be demonstrated regarding to design and application. Also, it is seen from literature that crane design related with mechatronics, control theory aspects are important and will be investigated for future works.