Crashworthiness Design Using a Hybrid Cellular Automaton Algorithm

2006 ◽  
Author(s):  
Neal M. Patel ◽  
Byung-Soo Kang ◽  
John E. Renaud
Keyword(s):  
Design Space ◽  
Manufacturing Cost ◽  
Optimization Approach ◽  
Concept Design ◽  
Design Synthesis ◽  
Response Surface Approximations ◽  
Complex Interactions ◽  
Cost Constraints ◽  
Passenger Safety ◽  
Crashworthiness Design

Crashworthiness design is an evolving discipline that combines vehicle crash simulation and design synthesis. The goal is to increase passenger safety subject to manufacturing cost constraints. The crashworthiness design process requires the modeling of the complex interactions involved in a crash event. Current approaches utilize a parameterized optimization approach that requires response surface approximations of the design space. This is due to the expensive nature of numerical crash simulations and the high nonlinearity and noisiness in the design space. These methodologies usually require a significant design effort to determine an initial design. In this research, a non-gradient approach to topology optimization is developed for crashworthiness design. The methodology utilizes the cellular automata paradigm to generate a concept design.

Crashworthiness Design Using Topology Optimization

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Neal M. Patel ◽  
Byung-Soo Kang ◽  
John E. Renaud ◽  
Andrés Tovar
Keyword(s):  
Topology Optimization ◽  
Design Space ◽  
Three Dimensional ◽  
Manufacturing Cost ◽  
Optimization Approach ◽  
Maximum Displacement ◽  
Efficient Manner ◽  
Response Surface Approximations ◽  
Cost Constraints ◽  
Crashworthiness Design

Crashworthiness design is an evolving discipline that combines vehicle crash simulation and design synthesis. The goal is to increase passenger safety subject to manufacturing cost constraints. The crashworthiness design process requires modeling of the complex interactions involved in a crash event. Current approaches utilize a parametrized optimization approach that requires response surface approximations of the design space. This is due to the expensive nature of numerical crash simulations and the high nonlinearity and noisiness in the design space. These methodologies usually require a significant effort to determine an initial design concept. In this paper, a heuristic approach to continuum-based topology optimization is developed for crashworthiness design. The methodology utilizes the cellular automata paradigm to generate three-dimensional design concepts. Furthermore, a constraint on maximum displacement is implemented to maintain a desired performance of the structures synthesized. Example design problems are used to demonstrate that the proposed methodology converges to a final topology in an efficient manner.

Optimization of Design Tolerances Through Response Surface Approximations

2002 ◽  
Vol 124 (3) ◽  
pp. 762-767 ◽  
Author(s):  
J. P. Jordaan ◽  
C. P. Ungerer
Keyword(s):  
Monte Carlo ◽  
Response Surface ◽  
Design Space ◽  
Analytical Relationship ◽  
Manufacturing Cost ◽  
Functional Requirements ◽  
Mechanical Assembly ◽  
Response Surface Approximations ◽  
Yield Values ◽  
Optimal Set

A methodology whereby the optimal set of design tolerances is assigned to the dimensions of a general mechanical assembly, is developed and tested. The manufacturing cost is minimized, while the design is constrained to a specified probability of meeting functional requirements, called the yield of the design. An analytical relationship for the assembly yield surface is generally unknown, and use is made of response surface approximations in the optimization algorithm. Yield values are determined at design space points through Monte Carlo simulations, seen as the response surface experiments. The methodology is benchmarked on example problems from the literature, and the optimum compares superior to published results.

scholarly journals A new stress-based topology optimization approach for finding flexible structures

2021 ◽  
Author(s):  
Martin Noack ◽  
Arnold Kühhorn ◽  
Markus Kober ◽  
Matthias Firl
Keyword(s):  
Topology Optimization ◽  
Stress State ◽  
Design Space ◽  
Flexible Structures ◽  
Optimization Approach ◽  
Principal Stresses ◽  
Output Displacement ◽  
Design Concepts ◽  
Flexible Designs ◽  
Gauss Points

AbstractThis paper presents a new FE-based stress-related topology optimization approach for finding bending governed flexible designs. Thereby, the knowledge about an output displacement or force as well as the detailed mounting position is not necessary for the application. The newly developed objective function makes use of the varying stress distribution in the cross section of flexible structures. Hence, each element of the design space must be evaluated with respect to its stress state. Therefore, the method prefers elements experiencing a bending or shear load over elements which are mainly subjected to membrane stresses. In order to determine the stress state of the elements, we use the principal stresses at the Gauss points. For demonstrating the feasibility of the new topology optimization approach, three academic examples are presented and discussed. As a result, the developed sensitivity-based algorithm is able to find usable flexible design concepts with a nearly discrete 0 − 1 density distribution for these examples.

Synthesis and Numerical Analysis of Compliant devices – A Topology Optimization Approach for Mechanisms and Robotic Systems

2021 ◽  
Author(s):  
Premanand Sathyanarayanamurthi ◽  
ARUNKUMAR GOPAL
Keyword(s):  
Topology Optimization ◽  
Optimization Design ◽  
Rectangular Domain ◽  
Dynamic State ◽  
Optimization Approach ◽  
Design And Development ◽  
Design Synthesis ◽  
Final Destination ◽  
Prototype Development ◽  
External Forces

Abstract The Topology Optimization design invariably shall be used in various applications like Aerojet designs, Aircraft Engineering designs and innovative systems for improving the efficiency of structure. The paper emphasizes more on general Topology Optimization design for a rectangular domain. The domain numerically analyzed with defined geometry setting and defined boundary conditions for finding the Stress and displacement. In this Topology Optimization Design synthesis, the result is suitable volume and mass reduction in the Aerojet application parts which further can be taken for Prototype development in 3D printing and experimentally test with safety characteristics and compares Objective functions chosen for design and development. The design can be used for other various automotive and aerospace devices based on deformation level and application of external forces. The Final destination of this design and development ends with passing Fatigue Endurance test cycle test pass condition in Aerojet and automotive vehicles in static and dynamic state.

Comparison of Piston Concept Design Solutions for Composite Cycle Engines Part II: Design Considerations

2021 ◽  
Author(s):  
Dimitrios Chatzianagnostou ◽  
Stephan Staudacher
Keyword(s):  
Gas Turbine ◽  
Design Space ◽  
Piston Compressor ◽  
Design System ◽  
Surface Load ◽  
Preliminary Design ◽  
Concept Design ◽  
Piston Engine ◽  
Engine Design ◽  
Cylinder Piston

Abstract Hecto pressure composite cycle engines with piston engines and piston compressors are potential alternatives to advanced gas turbine engines. The nondimensional groups limiting their design have been introduced and generally discussed in Part I [1]. Further discussion shows, that the ratio of effective power to piston surface characterizes the piston thermal surface load capability. The piston design and the piston cooling technology level limit its range of values. Reynolds number and the required ratio of advective to diffusive material transport limit the stroke-to-bore ratio. Torsional frequency sets a limit to crankshaft length and hence cylinder number. A rule based preliminary design system for composite cycle engines is presented. Its piston engine design part is validated against data of existing piston engines. It is used to explore the design space of piston components. The piston engine design space is limited by mechanical feasibility and the crankshaft overlap resulting in a minimum stroke-to-bore ratio. An empirical limitation on stroke-to-bore ratio is based on existing piston engine designs. It limits the design space further. Piston compressor design does not limit the piston engine design but is strongly linked to it. The preliminary design system is applied to a composite cycle engines of 22MW take-off shaft power, flying a 1000km mission. It features three 12-cylinder piston engines and three 20-cylinder piston compressors. Its specific fuel consumption and mission fuel burn are compared to an intercooled gas turbine with pressure gain combustion of similar technology readiness.

Backward Mapping Methodology for Design Synthesis

1999 ◽  
Author(s):  
Stephen C.-Y. Lu ◽  
Satish T. S. Bukkapatnam ◽  
Ping Ge ◽  
Nanxin Wang
Keyword(s):  
Engineering Design ◽  
Design Space ◽  
Initial Conditions ◽  
Early Stage ◽  
Critical Role ◽  
Product Development Process ◽  
Engineering System ◽  
Design Synthesis ◽  
Performance Space ◽  
Backward Mapping

Abstract Design efficiency and robustness at early stage of parametric engineering design play a critical role in reducing cycle time and improving product quality in the overall product development process. Usually, the “forward mapping” approach, is used to find designs, where the desirable performances are satisfied through large iterations of analysis and evaluation from design space to performance space. However, these approaches are time-consuming and involve blind search if the engineering system simulation models and/or initial conditions are not appropriately selected. On the other hand, common “reverse engineering” methods use domain-specific assumptions and are not effective in generic scenarios where the presumed conditions are violated. In this paper, a Backward Mapping Methodology for Design Synthesis (BMDS) is presented that can help conduct design synthesis rapidly and robustly at early stage of parametric engineering design. BMDS is a surrogate model-based approach that combines the strengths of metamodeling and statistics. It can help designers explicitly identify the robust design solutions that satisfy the designer-specified performance requirements through a “backward mapping” from the performance space directly to the design space. Preliminary case studies show its effectiveness and potential to be used as a generic early stage parametric design synthesis methodology in the future.

Optimization of the Dynamic Response of Semi-Submersibles: Influence of the Mooring System

2019 ◽  
Author(s):  
Shengtao Zhou ◽  
Frank Lemmer ◽  
Wei Yu ◽  
Po Wen Cheng ◽  
Chao Li ◽  
...  
Keyword(s):  
Life Cycle Cost ◽  
Design Space ◽  
Optimization Techniques ◽  
Optimization Process ◽  
Manufacturing Cost ◽  
Mooring System ◽  
Mooring Lines ◽  
Nsga Ii ◽  
Simulation Code ◽  
Set Up

Abstract The design and manufacturing cost of substructures is a major component of the total expenditure for a floating wind project. Applying optimization techniques to hull shape designs has become an effective way to reduce the life-cycle cost of a floating wind system. The mooring system is regarded as the component with the highest risk, mainly due to the poor accessibility. This paper extends the previous work by investigating the influences of the mooring design on the optimization process of a semisubmersible substructure. Two optimization loops are set up. In the first loop, only the main dimensions of a semi-submersible platform are parameterized without considering mooring lines (keep a constant mooring design). Nevertheless, the second loop introduces additional variables of the mooring lines. The objective is to minimize the tower-top displacement, fairlead fatigue damage, which are calculated by the in-house nonlinear dynamic simulation code SLOW, and the manufacturing cost of platform and mooring lines. The multi-objective optimization algorithm NSGA-II is employed to search for the optimal designs within the defined design space. The design space and the Pareto fronts are compared between the two optimizations. It is found that, although the mooring design does not have a significant impact on the platform design space, one obtains a different optimal set (Pareto front) if the mooring design and mooring loads are introduced into the platform optimization process. The results of this study are expected to give a better understanding in the relationship between platform and mooring design and serve as a basis for the optimization process of semi-submersible floating wind turbines.

scholarly journals Pareto Optimization for Subset Selection with Dynamic Cost Constraints

2019 ◽  
Vol 33 ◽  
pp. 2354-2361 ◽  
Author(s):  
Vahid Roostapour ◽  
Aneta Neumann ◽  
Frank Neumann ◽  
Tobias Friedrich
Keyword(s):  
Greedy Algorithms ◽  
Subset Selection ◽  
Pareto Optimization ◽  
Experimental Investigations ◽  
Optimization Approach ◽  
Submodular Optimization ◽  
Approximation Quality ◽  
Cost Constraints ◽  
Changes Over Time ◽  
Over Time

In this paper, we consider the subset selection problem for function f with constraint bound B which changes over time. We point out that adaptive variants of greedy approaches commonly used in the area of submodular optimization are not able to maintain their approximation quality. Investigating the recently introduced POMC Pareto optimization approach, we show that this algorithm efficiently computes a φ = (αf/2)(1− α1f )-approximation, where αf is the sube modularity ratio of f, for each possible constraint bound b ≤ B. Furthermore, we show that POMC is able to adapt its set of solutions quickly in the case that B increases. Our experimental investigations for the influence maximization in social networks show the advantage of POMC over generalized greedy algorithms.

scholarly journals Reducing the Frame Vibration of Delta Robot in Pick and Place Application: An Acceleration Profile Optimization Approach

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Hongtai Cheng ◽  
Wei Li
Keyword(s):  
Surrogate Model ◽  
High Speed ◽  
Gaussian Process Regression ◽  
Frame Structure ◽  
Manufacturing Cost ◽  
Optimization Approach ◽  
Pick And Place ◽  
Delta Robot ◽  
Profile Optimization ◽  
Acceleration Profile

Delta robot is typically mounted on a frame and performs high speed pick and place tasks from top to bottom. Because of its outstanding accelerating capability and higher center of mass, the Delta robot can generate significant frame vibration. Existing trajectory smoothing methods mainly focus on vibration reduction for the robot instead of the frame, and modifying the frame structure increases the manufacturing cost. In this paper, an acceleration profile optimization approach is proposed to reduce the Delta robot-frame vibration. The profile is determined by the maximum jerk, acceleration, and velocity. The pick and place motion (PPM) and resulting frame vibration are analyzed in frequency domain. Quantitative analysis shows that frame vibration can be reduced by altering those dynamic motion parameters. Because the analytic model is derived based on several simplifications, it cannot be directly applied. A surrogate model-based optimization method is proposed to solve the practical issues. By directly executing the PPM with different parameters and measuring the vibration, a model is derived using Gaussian Process Regression (GPR). In order to reduce the frame vibration without sacrificing robot efficiency, those two goals are fused together according to their priorities. Based on the surrogate model, a single objective optimization problem is formulated and solved by Genetic Algorithm (GA). Experimental results show effectiveness of the proposed method. Behavior of the optimal parameters also verifies the robot-frame vibration mechanism.

Material Optimization for Design Improvement of Crash Energy Absorbers

2010 ◽  
Author(s):  
Hesham Ibrahim
Keyword(s):  
Impact Energy ◽  
Design Space ◽  
Thickness Distribution ◽  
Optimization Approach ◽  
Optimum Thickness ◽  
Energy Absorber ◽  
Design Improvement ◽  
Material Type ◽  
Thin Walled ◽  
Energy Absorbers

Crash energy absorbers in the form of thin walled tubes play a significant role in mitigating the harmful effects of frontal vehicles accidents on occupants. Specific energy absorbed (SEA), which is the ratio of impact energy absorbed to mass, is usually used to evaluate the efficiency of crash energy absorbers. A good design of a crash energy absorber must maximize the amount of impact energy that can be absorbed with a certain weight. The formal approach that has been used to improve the design of crash energy absorbers is to employ optimization to search for the optimum thickness distribution that maximizes SEA. This approach can be conceptualized as searching the design space in only one dimension (thickness). In this paper, a new dimension is added to the design space (material type). The proposed approach considers the type of material as a variable. An optimum design is then found by not only searching for the optimum thickness distribution, but also by selecting the optimum material type. The approach is demonstrated to the design improvement of a crash energy absorber in the form of a thin walled tube of square cross section. Steel and magnesium have been used as the two material alternatives. Magnesium has been selected due to its low density that had made it a promising candidate for use as a structural material in the automobile manufacturing. The results have shown that following the proposed technique, SEA has been increased by 54% compared to the value obtained through following the formal design optimization approach.

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