A Structural Optimization Method for Universal Design of Compliant Mechanism Scissors

2009 ◽  
Author(s):  
Kazuhiro Izui ◽  
Kiyoshi Yokota ◽  
Takayuki Yamada ◽  
Shinji Nishiwaki ◽  
Masataka Yoshimura
Keyword(s):  
Structural Optimization ◽  
Universal Design ◽  
Compliant Mechanism ◽  
Design Method ◽  
Optimization Technique ◽  
Optimization Method ◽  
Design Criterion ◽  
Design Solution ◽  
Design Criteria ◽  
Level Set Function

This paper proposes a structural optimization-based method for the design of compliant mechanism scissors in which the proposed design criteria are based on universal design principles. The first design criterion is the distance from the hand-grip to the center of gravity of the scissors, which should be minimized to reduce the physical effort required of the people using the device. The second design criterion is that of failure tolerance, where the effects of traction applied in undesirable directions upon the performance of the compliant mechanism should be minimized. Based on the proposed design criteria, a multiobjective optimization problem for the universal design of a compliant mechanism scissors is formulated. Furthermore, to obtain an optimal configuration, a new type of topology optimization technique using the level set function to represent structural boundaries is employed. This optimization technique enables rapid verification of resulting design configurations since the boundary shapes of the obtained design solution candidates can be easily converted to finite element models which are then used in large deformation analyses. Finally, the proposed design method is applied to design examples. The optimal configurations obtained by the proposed method provide good universal design performance, indicating the effectiveness and usefulness of the proposed method.

Structural Optimization Design of an Aircraft Metal-Composite Wing

2013 ◽  
Vol 341-342 ◽  
pp. 519-523
Author(s):  
Ya Hui Zhang ◽  
Ji Hong Zhu ◽  
Jun Shuo Li ◽  
Wei Hong Zhang
Keyword(s):  
Structural Optimization ◽  
Optimization Design ◽  
Optimization Method ◽  
Design Solution ◽  
Metal Composite ◽  
Concept Design ◽  
Obvious Effect ◽  
Reinforced Composite ◽  
Three Phase ◽  
Composite Wing

The problem of metal-composite wing structural optimization is discussed and a strategy is presented. Topology optimization method is applied to provide load transferring path of structure for concept design. Size, shape and other optimization method are used to provide detailed design for individual components. A three-phase optimization method is discussed for fiber reinforced composite laminate skin. Optimal parameters include ply angle, percentage, thickness, layer shape and sequence. The design of laminate for ease of manufacture is based on a set of manufacturing constraints. This paper deals with a total optimal design solution for aileron structure of an aircraft. The result satisfies all the requirements of strength and stability, and has obvious effect of weight loss.

scholarly journals Motion-Based Design of Passive Damping Devices to Mitigate Wind-Induced Vibrations in Stay Cables

Vibration ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 269-289 ◽  
Author(s):  
Javier Naranjo-Pérez ◽  
Javier Jiménez-Manfredi ◽  
Javier Jiménez-Alonso ◽  
Andrés Sáez
Keyword(s):  
Objective Function ◽  
Design Method ◽  
Optimization Method ◽  
Design Criterion ◽  
Passive Damping ◽  
Characteristic Parameters ◽  
Additional Function ◽  
Wind Action ◽  
Multi Objective ◽  
Stay Cables

Wind action can induce large amplitude vibrations in the stay cables of bridges. To reduce the vibration level of these structural elements, different types of passive damping devices are usually installed. In this paper, a motion-based design method is proposed and implemented in order to achieve the optimum design of different passive damping devices for stay cables under wind action. According to this method, the design problem is transformed into an optimization problem. Thus, its main aim is to minimize the different terms of a multi-objective function, considering as design variables the characteristic parameters of each considered passive damping device. The multi-objective function is defined in terms of the scaled characteristic parameters, one single-function for each parameter, and an additional function that checks the compliance of the considered design criterion. Genetic algorithms are considered as a global optimization method. Three passive damping devices have been studied herein: viscous, elastomeric and friction dampers. As a benchmark structure, the Alamillo bridge (Seville, Spain), is considered in order to validate the performance of the proposed method. Finally, the parameters of the damping devices designed according to this proposal are successfully compared with the results provided by a conventional design method.

Universal Design Considering Physical Characteristics of Diverse Users

2019 ◽  
Vol 13 (4) ◽  
pp. 517-525
Author(s):  
Masato Inoue ◽  
Wataru Suzuki ◽  
◽  
Keyword(s):  
Universal Design ◽  
Design Method ◽  
Physical Characteristics ◽  
Design Solution ◽  
User Requirements ◽  
User Characteristics ◽  
Control Factors ◽  
Design Variables ◽  
Noise Factors

To achieve a universal design that satisfies diverse user requirements associated with aging and internationalization, designers must make a decision based on diverse user requirements. Designers have generally incorporated average human physical characteristics in their designs. Thus, user limitations are critically important. Traditional design methods often regard engineering and product design as iterative processes based on point values. However, when user information is represented as a point value, the resulting product satisfies only that specific user group and does not necessarily satisfy diverse user groups. This study proposes a universal design method that obtains diversely ranged design solutions for user requirements. The proposed method defines diverse user requirements, design variables, and user characteristics as sets, which range in value. To represent user information accurately, users are classified into numerous groups using classification techniques. Design variables are divided into two types: control and noise. Control factors are designer-controllable variables that are based on design specifications. Noise factors are designer-uncontrollable variables representing user characteristics. To derive a ranged design solution set, designers clarify the relationship between performance and design variables. Ranged solutions satisfying required performance are derived for each group using all relational expressions and ranged variable values. The combinations of divided design variables that cannot satisfy the required performance are eliminated from the design proposal, and the narrowed range of design variables become ranged solutions. The ranged solutions are derived for each group, and the common range of design variables is the ranged solution for all users. This paper chooses the design problem of the strap height of a train as a case study of the proposed universal design method. In this case study, we consider diverse user requirements based on the variability of physical characteristics. This paper discusses the suitability of our proposed approach for obtaining ranged solutions that reflect the physical characteristics of diverse users.

Design of Compliant Thermal Actuators Using Structural Optimization Based on the Level Set Method

2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Takayuki Yamada ◽  
Shintaro Yamasaki ◽  
Shinji Nishiwaki ◽  
Kazuhiro Izui ◽  
Masataka Yoshimura
Keyword(s):  
Structural Optimization ◽  
Level Set Method ◽  
Level Set ◽  
Compliant Mechanisms ◽  
Optimization Method ◽  
Equilibrium Equations ◽  
Thermal Actuators ◽  
Level Set Function ◽  
Initialization Scheme ◽  
Set Function

Compliant mechanisms are designed to be flexible to achieve a specified motion as a mechanism. Such mechanisms can function as compliant thermal actuators in micro-electromechanical systems by intentionally designing configurations that exploit thermal expansion effects in elastic material when appropriate portions of the mechanism structure are heated or are subjected to an electric potential. This paper presents a new structural optimization method for the design of compliant thermal actuators based on the level set method and the finite element method (FEM). First, an optimization problem is formulated that addresses the design of compliant thermal actuators considering the magnitude of the displacement at the output location. Next, the topological derivatives that are used when introducing holes during the optimization process are derived. Based on the optimization formulation, a new structural optimization algorithm is constructed that employs the FEM when solving the equilibrium equations and updating the level set function. The re-initialization of the level set function is performed using a newly developed geometry-based re-initialization scheme. Finally, several design examples are provided to confirm the usefulness of the proposed structural optimization method.

Strength Optimization of Infant Pop-Up Seat Frame Using Discrete Material and Thickness Optimization

2021 ◽  
Vol 11 (3) ◽  
pp. 1-20
Author(s):  
YeongJo Ju ◽  
Euysik Jeon
Keyword(s):  
Optimal Design ◽  
High Strength Steel ◽  
Design Method ◽  
High Strength ◽  
Optimization Method ◽  
Design Criterion ◽  
Thickness Optimization ◽  
Element Analysis ◽  
Strength Design ◽  
Seat Frame

In this paper, the authors proposed an optimal design method for the strength design of infant pop-up seat frame combined with rear seats for infants, children, and adults, not removable booster seats or car seats. Frame strength design was performed using discrete material and thickness optimization (DMTO) method considering high strength steel (HSS) and advanced high strength steel (AHSS). Structural design using the Section 4 link mechanism was performed, and the weakness of the seat frame due to static load was confirmed through finite element analysis. An optimal design criterion was established by carrying out a case study to derive the limiting conditions according to static and dynamic loads. In consideration of these criteria, the optimal design according to d-optimal and discrete Latin-hypercube (DLH) was performed among the design of experiments (DOE). And the strength of the pop-up seat frame for infants according to each DOE was checked, and the strength optimization method was suggested by comparing the lightweight ratio.

Design of Mechanical Structures Considering Harmonic Loads Using Level Set-Based Topology Optimization

2012 ◽  
Author(s):  
Takayuki Yamada ◽  
Toshiro Matsumoto ◽  
Shinji Nishiwaki
Keyword(s):  
Topology Optimization ◽  
Level Set ◽  
Design Method ◽  
Optimization Method ◽  
Adjoint Equations ◽  
Topology Optimization Problem ◽  
Level Set Function ◽  
Elastic Design ◽  
Objective Functional ◽  
Topology Optimization Method

This paper presents an optimum design method for mechanical structures considering harmonic loads using a level set-based topology optimization method and the Finite Element Method (FEM). First, we briefly discuss the level set-based topology optimization method. Second, a topology optimization problem is formulated for a dynamic elastic design problem using level set boundary expressions. The objective functional is set to minimize the displacement at specific boundaries. Based on this formulation, the topological sensitivities of the objective functional are derived. Next, a topology optimization algorithm is proposed that uses the FEM to solve the equilibrium and adjoint equations, and when updating the level set function. Finally, several numerical examples are provided to confirm the validity and utility of the proposed method.

scholarly journals On the design of a novel fully compliant spherical four-bar mechanism

2019 ◽  
Vol 11 (9) ◽  
pp. 168781401987954
Author(s):  
Volkan Parlaktaş ◽  
Engin Tanık ◽  
Çağıl Merve Tanık
Keyword(s):  
Compliant Mechanism ◽  
Design Method ◽  
Optimization Method ◽  
Maximum Output ◽  
Element Analysis ◽  
Free Position ◽  
Flexural Hinges ◽  
Arc Lengths ◽  
The Relationship ◽  
Novel Design

In this article, a novel fully compliant spherical four-bar mechanism is introduced and its generalized design methodology is proposed. The original fully compliant mechanism lies on a plane at the free position (undeflected position); therefore, it has the advantages of ease of manufacturing, minimized parts, and no backlash. First, the mobility conditions of the mechanism are obtained. The dimensions of the mechanism are optimally calculated for maximum output rotation, while keeping the deflection of flexural hinges at an acceptable range. Using an optimization method, design tables are prepared to display the relationship between arc lengths and corresponding deflections of flexural hinges. Input–output torque relationship and stresses at compliant segments are obtained analytically. A mechanism dimensioned by this novel design method is analyzed by a finite element analysis method, and the analytical results are verified. Finally, the mechanism is manufactured and it is ensured that the deflections of the compliant segments are consistent with the theoretical results.

A New Structural Optimization Method Based on Group Hunting of Animals: Hunting Search (HuS)

2010 ◽  
Author(s):  
R. Oftadeh ◽  
M. J. Mahjoob
Keyword(s):  
Structural Optimization ◽  
Numerical Optimization ◽  
Optimization Problems ◽  
Optimization Technique ◽  
Harmony Search ◽  
Optimization Methods ◽  
Optimization Method ◽  
Global Optimization Methods ◽  
Multi Level ◽  
Group Hunting

This paper presents a novel structural optimization algorithm based on group hunting of animals such as lions, wolves, and dolphins. Although these hunters have differences in the way of hunting but they are common in that all of them look for a prey in a group. The hunters encircle the prey and gradually tighten the ring of siege until they catch the prey. In addition, each member of the group corrects its position based on its own position and the position of other members. If the prey escapes from the ring, the hunters reorganize the group to siege the prey again. A benchmark numerical optimization problems is presented to show how the algorithm works. Three benchmark structural optimization problems are also presented to demonstrate the effectiveness and robustness of the proposed Hunting Search (HuS) algorithm for structural optimization. The objective in these problems is to minimize the weight of bar trusses. Both sizing and layout optimization variables are included, too. The proposed algorithm is compared with other global optimization methods such as CMLPSA (Corrected Multi-Level & Multi-Point Simulated Annealing) and HS (Harmony Search). The results indicate that the proposed method is a powerful search and optimization technique. It yields comparable and in some cases, better solutions compared to those obtained using current algorithms when applied to structural optimization problems.

The Thermal-Circuit High-Speed Collaboration Layout Design for an Electronic System With Multi-Agent Method

2007 ◽  
Author(s):  
Shintaro Hayashi ◽  
Yoshiharu Iwata ◽  
Ryohei Satoh ◽  
Kozo Fujimoto
Keyword(s):  
System Design ◽  
Design Method ◽  
Electronic System ◽  
Optimization Method ◽  
Layout Design ◽  
Design Solution ◽  
Design System ◽  
Pareto Solution ◽  
Thermal Circuit ◽  
Design Time

Recently, electronics systems have become more complex resulting in a need for system design method that considers multiple physical phenomenons. However, it is difficult at the electronic system design level to reduce the design time and realize high precision. We have developed a collaborative highspeed thermal/circuit design method with a modularized model [1–2]. In this paper, we reconsider the optimization method of this design system. We obtain the local minimum solution for a very high-density device system. However, because the constraints associated with both thermal and electrical design become very strong, we applied an agent-oriented optimization method in defining the boundary conditions between device module and board module to ease the constraints on the thermal layout design. This method is characterized by making the design for device module design intelligent. In a case study, we achieved more than a 20% improvement in the design solution in the Pareto curve. We also reduced the design time by more than 10 times (one weight pattern: about 30sec, Pareto solution set: about 600sec). This enables the designer of electronics system to compare Pareto solution sets within a short time and to evaluate many different layout designs during the rough design phase of a system design.

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