Papers by Erkki Taitokari
Advances in Fuzzy Systems, 2011
In this study, the basic engineering principles, goals, and constraints are all combined to fuzzy... more In this study, the basic engineering principles, goals, and constraints are all combined to fuzzy methodology and applied to design of optimally pressurised containers emphasising the ecological and durability merits of various materials. The present fuzzy heuristics approach is derivable from generalisation of conventional analytical optimisation method into fuzzy multitechnical tasks. In the present approach, first the goals and constraints of the end-user are identified. Then decision variables are expressed as functions of the design variables. Their desirable ranges and biases are defined using the same fuzzy satisfaction function form. The optimal result has highest total satisfaction. These are then checked and fine-tuned by finite element method FEM. The optimal solution is the ecoplastic vessel, and aluminium was close. The method reveals that optimum depends strongly on the preset goals and values of the producer, society, and end-user.
Mechanical Engineering Research, Jan 20, 2013
In this study the aim is to present results of bridge concept design using heuristic fuzzy optimu... more In this study the aim is to present results of bridge concept design using heuristic fuzzy optimum design and FEM. The bridge concept is chosen as the basic suspension type. The deck plate rests on four supports. The middle supports are towers with suspension cables to lift up the bridge plate for minimising its deflection and bending stresses. Mass distribution load and flutter loading act on the plate. Geometric design variables are topology and dimensions of cables and deck. Material variable options are low strength and high strength steel. Decision variables are based on design variables. The main ones are cost and safety factors. The total goal is maximization of the fuzzy satisfaction of the user on all decision variables. The same optimal geometry is obtained for both steel options giving nearly equal performance. The softer steel option is preferable due lower cost. The model and FEM results agree reasonably in stresses and deflections. The fuzzy model used is shown to be an extension of probabilistic models.
Optimal Design Of Innovative Composite Flat Ends Subject To External Pressure
WIT Transactions on the Built Environment, Feb 25, 2002
WIT Transactions on the Built Environment, May 4, 2005
In this paper results of studying the task of increasing the reliability of piping branch connect... more In this paper results of studying the task of increasing the reliability of piping branch connections of stainless steel by redesign are discussed. The background is recurrent problems of fracture failures of conventional constructions. Optimum design algorithm and models are applied to a 2D branch section with the fuzzy goal of achieving a small enough toe area and a large enough local strain fatigue life. The design variables are fillet size and form. Stress concentration reduction by local plastic yielding is taken into account using the Ramberg Osgood material model. The conventional 3D piping branch case is optimised using the required method of standards and FEM. An innovative solution is synthesised using fibre based filament strengtheners in thin pipes. It is designed optimally by FEM and the elastic stress concentration at the toe can be reduced from below ten to close to one. This means that considerable increases in mean time to failure can be achieved cost effectively compared to other solutions. Keywords: shape and topology optimisation industrial examples of design optimisation, performance based design.
Advances in Fuzzy Systems, 2011
In this study the basic engineering principles, goals, and constraints are all combined with fuzz... more In this study the basic engineering principles, goals, and constraints are all combined with fuzzy methodology and applied to optimally design sandwich panel circular plate roofs for large vessels loaded statically and dynamically. These panels are made up of two stiff, strong veneer skins separated by vertical and peripheral stiffener plates. Advantages are high strength, lightweight, and sustainability. In the present approach, first the goals and constraints of the end user are identified and expressed as decision variables which are formulated using the engineering variables for materials, geometry, and function. Then same consistent fuzzy satisfaction functions are formed over the desired ranges to suit the customer's desires. The risk of extreme dynamic loadings exciting resonance is studied by natural frequency and mode analysis by FEM and analytical models. The results show the most critical locations and give guidelines for innovative remedies of the concept before detailed FEM analyses to finalize the design.
WIT Transactions on the Built Environment, Apr 18, 2006
The main purpose of this study is to present results of the design and damage analysis of industr... more The main purpose of this study is to present results of the design and damage analysis of industrial vessel shell microstructures made of fibre reinforced plastic laminates and subject to mechanical and aggressive chemical loads due to sulphuric and hydrochloric acids and high temperatures. Methods to obtain optimal performance microstructure are use of balanced and symmetric laminate layering with optimal fibre strengthening directions and volume fractions. Optimal selection of chemically resistant fibres and matrix is essential for endurance. Use of thick enough walls is cost-effective for vessel bottoms. Two vessel winding manufacturing technologies are compared for optimal selection.
Mechanical Engineering Research, Aug 8, 2012
In this study the results of optimum design of perforated cylindrical shell dryings drums are con... more In this study the results of optimum design of perforated cylindrical shell dryings drums are considered. These drums are used for pressurised drying of wet mass. They are important also in filter technology in macro, micro and nanoscales. The goal is formulated as maximisation of customer satisfaction on the most important decision variables. These are the fatigue endurance measured by crack propagation life, rate of water removal from mass through holes, risk of crack initiation and total cost. For perforated cylinders and plates basic engineering models are developed to get loads on the drum and to get equivalent material models to be used cost effectively in FEM. The validity of the surrogate models is tested using detailed FEM models. The results give a reasonable trade-off between many contradictory requirements. One optimal geometry is obtained and the softer steel is preferable due to better fatigue endurance and lower costs. Different surrogate models apply for static and dynamic loading.
WIT Transactions on the Built Environment, 2004
The main purpose of this study is to present the results of the testing and modelling of compress... more The main purpose of this study is to present the results of the testing and modelling of compression and heat-treated birch wood as constructional component. Using some special and some patented treatments the hardness and bending strength of components can be increased by up to fifty per cent. Since wood is macroscopically and microstructurally an orthotropic material, reliable prediction of its mechanical and failure behaviour requires verified models. Basic mechanical testing is made with samples to obtain strength and damage locations and modes. SEM pictures are used to reveal microstructural features. These test results and measured or estimated material model values are used to make FEM simulations. Analytical cellular solid models are used to derive orthotropic elastic and strength properties. Also FEM models are made to study the behaviour of the cellular microstructures. Relationships between the micro- and macromodels are derived. The results of tests and analytical models...
High Performance Structures and Materials III, 2006
The main purpose of this study is to present results of the design and damage analysis of industr... more The main purpose of this study is to present results of the design and damage analysis of industrial vessel shell microstructures made of fibre reinforced plastic laminates and subject to mechanical and aggressive chemical loads due to sulphuric and hydrochloric acids and high temperatures. Methods to obtain optimal performance microstructure are use of balanced and symmetric laminate layering with optimal fibre strengthening directions and volume fractions. Optimal selection of chemically resistant fibres and matrix is essential for endurance. Use of thick enough walls is cost-effective for vessel bottoms. Two vessel winding manufacturing technologies are compared for optimal selection.
Advances in Fuzzy Systems, 2011
In this study, the basic engineering principles, goals, and constraints are all combined to fuzzy... more In this study, the basic engineering principles, goals, and constraints are all combined to fuzzy methodology and applied to design of optimally pressurised containers emphasising the ecological and durability merits of various materials. The present fuzzy heuristics approach is derivable from generalisation of conventional analytical optimisation method into fuzzy multitechnical tasks. In the present approach, first the goals and constraints of the end-user are identified. Then decision variables are expressed as functions of the design variables. Their desirable ranges and biases are defined using the same fuzzy satisfaction function form. The optimal result has highest total satisfaction. These are then checked and fine-tuned by finite element method FEM. The optimal solution is the ecoplastic vessel, and aluminium was close. The method reveals that optimum depends strongly on the preset goals and values of the producer, society, and end-user.
Organic Process Research & Development, 2005
In this paper results of studying the task of increasing the reliability of piping branch connect... more In this paper results of studying the task of increasing the reliability of piping branch connections of stainless steel by redesign are discussed. The background is recurrent problems of fracture failures of conventional constructions. Optimum design algorithm and models are applied to a 2D branch section with the fuzzy goal of achieving a small enough toe area and a large enough local strain fatigue life. The design variables are fillet size and form. Stress concentration reduction by local plastic yielding is taken into account using the Ramberg Osgood material model. The conventional 3D piping branch case is optimised using the required method of standards and FEM. An innovative solution is synthesised using fibre based filament strengtheners in thin pipes. It is designed optimally by FEM and the elastic stress concentration at the toe can be reduced from below ten to close to one. This means that considerable increases in mean time to failure can be achieved cost effectively co...
广东省公路院举办 qc小组 专题教育
公路测设简讯, 1996
In this study the aim is to present results of bridge concept design using heuristic fuzzy optimu... more In this study the aim is to present results of bridge concept design using heuristic fuzzy optimum design and FEM. The bridge concept is chosen as the basic suspension type. The deck plate rests on four supports. The middle supports are towers with suspension cables to lift up the bridge plate for minimising its deflection and bending stresses. Mass distribution load and flutter loading act on the plate. Geometric design variables are topology and dimensions of cables and deck. Material variable options are low strength and high strength steel. Decision variables are based on design variables. The main ones are cost and safety factors. The total goal is maximization of the fuzzy satisfaction of the user on all decision variables. The same optimal geometry is obtained for both steel options giving nearly equal performance. The softer steel option is preferable due lower cost. The model and FEM results agree reasonably in stresses and deflections. The fuzzy model used is shown to be a...
Optimal Design of Sandwich Vessel Roofs
In this study the basic engineering principles, goals and constraints are all combined to fuzzy m... more In this study the basic engineering principles, goals and constraints are all combined to fuzzy methodology and applied to design optimally sandwich panel circular plate roofs for large vessels. These panels are made up of two stiff, strong veneer skins separated by vertical and peripheral stiffener plates. Advantages are high strength and lightweight and sustainability. In the present approach first the goals and constraints of the end-user are identified and expressed as decision variables which are formulated using the engineering variables for materials, geometry and function. Then same consistent fuzzy satisfaction functions are formed over the desired ranges to suit the customer's desires of mean and bias. The results show the most critical locations and allow fast checks of innovative remedies. Detailed FEM analyses ensure the optimality of the chosen concept.
Komposiittivaipan moderni optimisuunnittelu ja toteutus
Optimal Design of Sandwich Vessel Roofs
ABSTRACT
Dynamics Design of Vessels of Fibre Reinforced Plastic with Steel Shafts for Fluid Mixing
ABSTRACT
In this study the results of optimum design of perforated cylindrical shell dryings drums are con... more In this study the results of optimum design of perforated cylindrical shell dryings drums are considered. These drums are used for pressurised drying of wet mass. They are important also in filter technology in macro, micro and nanoscales. The goal is formulated as maximisation of customer satisfaction on the most important decision variables. These are the fatigue endurance measured by crack propagation life, rate of water removal from mass through holes, risk of crack initiation and total cost. For perforated cylinders and plates basic engineering models are developed to get loads on the drum and to get equivalent material models to be used cost effectively in FEM. The validity of the surrogate models is tested using detailed FEM models. The results give a reasonable trade-off between many contradictory requirements. One optimal geometry is obtained and the softer steel is preferable due to better fatigue endurance and lower costs. Different surrogate models apply for static and dynamic loading.
Advances in Fuzzy Systems
In this study the basic engineering principles, goals, and constraints are all combined with fuzz... more In this study the basic engineering principles, goals, and constraints are all combined with fuzzy methodology and applied to optimally design sandwich panel circular plate roofs for large vessels loaded statically and dynamically. These panels are made up of two stiff, strong veneer skins separated by vertical and peripheral stiffener plates. Advantages are high strength, lightweight, and sustainability. In the present approach, first the goals and constraints of the end user are identified and expressed as decision variables which are formulated using the engineering variables for materials, geometry, and function. Then same consistent fuzzy satisfaction functions are formed over the desired ranges to suit the customer's desires. The risk of extreme dynamic loadings exciting resonance is studied by natural frequency and mode analysis by FEM and analytical models. The results show the most critical locations and give guidelines for innovative remedies of the concept before detailed FEM analyses to finalize the design.
Advances in Fuzzy Systems, 2011
In this study, the basic engineering principles, goals, and constraints are all combined to fuzzy... more In this study, the basic engineering principles, goals, and constraints are all combined to fuzzy methodology and applied to design of optimally pressurised containers emphasising the ecological and durability merits of various materials. The present fuzzy heuristics approach is derivable from generalisation of conventional analytical optimisation method into fuzzy multitechnical tasks. In the present approach, first the goals and constraints of the end-user are identified. Then decision variables are expressed as functions of the design variables. Their desirable ranges and biases are defined using the same fuzzy satisfaction function form. The optimal result has highest total satisfaction. These are then checked and fine-tuned by finite element method FEM. The optimal solution is the ecoplastic vessel, and aluminium was close. The method reveals that optimum depends strongly on the preset goals and values of the producer, society, and end-user.
Uploads
Papers by Erkki Taitokari