J. Mech. Des. Aug 2020, 142(8): 081401
Pubished online: February 14, 2020
Guanglu Zhang, Elissa Morris, Douglas Allaire, Daniel A. McAdams
J. Mech. Des. Aug 2020, 142(8): 081401
Pubished online: February 14, 2020
Many modern products, such as automobiles, aircrafts, laptops and smartphones, are engineered systems. The performance, function, and architecture of an engineered system continuously changes and improves over time. For example, cell phones of the 1990’s were limited to phone calls and text messages. Today's cell phones are computers capable of cinematography and reading the news. Research in engineered system evolution goes beyond tracking and predicting the technical performance and the functional and architectural changes of existing engineered systems. This research also studies how and why these changes occur and searches for causal factors behind these evolutions. The results of this research are valuable for designers, R&D managers, investors, and policy makers by aiding the generation of innovative design concepts, setting reasonable R&D targets, investing in promising technologies, and developing effective incentive policies. This paper summarizes key research questions, identifies pioneering literature, and discusses the opportunities and challenges for future research in engineered system evolution. Importantly, a free access database is provided for facilitating future research in this area. The database currently includes more than 100,000 data points that belong to 31 technical performance metric categories of 7 engineering systems (i.e., passenger aircraft, orbital launch system, automobile, computer, refrigerator, lamp, and direct-fire ground weapon systems) and their components.
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Yi Xiong, Pham Luu Trung Duong, Dong Wang, Sang-In Park, Qi Ge, Nagarajan Raghavan, David W. Rosen
J. Mech. Des. Oct 2019, 141(10): 101101
The capabilities of additive manufacturing offer significant potential for revolutionizing existing product development processes by creating products that are rich in shape, material, hierarchical, and functional complexities. However, searching through design solutions in such a multidimensional design space is a challenging task. In this study, the authors propose a holistic approach that applies data-driven methods in successive stages of design search and optimization. More specifically, a two-step surrogate model-based design method is proposed for the embodiment and detailed stages of product design. A Bayesian network classifier is used in embodiment design as the reasoning framework for exploring the design space. A Gaussian process regression model is then used as the evaluation function during optimization, allowing for the exploitation of the design space during the optimization of the detailed design. These models are constructed based on one dataset created using Latin hypercube sampling and then refined using Markov Chain Monte Carlo sampling. This cost-effective data-driven approach is demonstrated by designing a customized ankle brace that has tunable mechanical performance by using a highly stretchable design concept with tailored stiffnesses in different directions.
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Merel van Diepen and Kristina Shea
J. Mech. Des 141(10), 101402; doi: 10.1115/1.4043314
Soft locomotion robots are intrinsically compliant and have a large number of degrees of freedom. However, the hand-design of soft robots is often a lengthy trail-and-error process. This paper presents the computational design of virtual, soft locomotion robots using an approach that integrates simulation feedback. The Computational Design Synthesis (CDS) approach consists of three stages: (1) generation, (2) evaluation through simulation, and (3) optimization.
Designs are generated using a spatial grammar that explicitly guides the type of solutions generated and excludes infeasible designs. The soft material simulation method is stable and sufficiently fast for use in a highly iterative simulated annealing search process. The resulting virtual designs exhibit a large variety of expected and unexpected gaits, thus demonstrating the capabilities of the method. Finally, the optimization results and the spatial grammar are analyzed to understand and map the challenges of the problem and the search space.
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Mohammad Hassannezhad, Marco Cantamessa, Francesca Montagna and P. John Clarkson
J. Mech. Des 141(8), 081101; doi: 10.1115/1.4042614
A key challenge in lengthy and labor-intensive design projects is leveraging knowledge and expertise. Tools are needed that reflect the social and technical characteristics of design processes. Such integrated modelling is particularly critical in the early stages of design where information is imprecise and decisions have significant consequence. This paper contributes to the development of Actor-Based Signposting (ABS) - a dynamic method that combines the Activity-based and Agent-based concepts of process modelling. This approach enables individuals to be adaptive in satisfying the local objectives of their own jobs while complying with the global objectives of the rest of the team/entire system. Outcomes from this work are significant because they can be used for predicting the trajectory of a design process by allowing decision-makers to understand what task to do next, whom to assign a task given the availability of resources, and the levels of knowledge and expertise required. Two case studies are presented and results demonstrate a range of insights that could enhance managers’ decision-making capabilities and opportunities for future research are discussed.
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Design and Optimization of Graded Cellular Structures with Triply Periodic Level Surface-Based Topological Shapes
Dawei Li, Ning Dai, Yunlong Tang, Guoying Dong, and Yaoyao Fiona Zhao
J. Mech. Des 141(7), 071402
Periodic cellular structures with excellent mechanical properties widely exist in nature. Examples include shark skin, bone structure, etc. This research introduces a generative design and optimization method for triply periodic level surface (TPLS)-based functionally graded cellular structures. In the proposed method, the density distribution is controlled so that the TPLS-based cellular structures can achieve better structural or thermal performances without increasing the weight of the structure. A series of different design specifications are used for validating the design and optimization methods introduced in this work. Effectiveness and robustness of the obtained structures are analyzed using both finite element analysis and experiments. Results from these studies show that the functional gradient cellular structure is much stiffer and has better heat conductivity than the uniform cellular structure.
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Andrew S. Gillman; Kazuko Fuchi; Philip R. Buskohl
J. Mech. Des. 141(4), 041401 (Jan 11, 2019)
Origami, the ancient art of paper folding, is finding numerous uses in scientific and engineering applications because of the combined advances in mathematics, computer science, and computational geometry. From deployment of solar arrays and antennas to design of robots and modeling of protein folding, origami provides an efficient means of compaction and coordinated motion. Many of the design and analysis tools for origami have relied on both rigid body mechanics and adaptation of well-known fold patterns for engineering applications. This work expands on these approaches through development of an automated design tool for fold pattern discovery, while accounting for non-rigid (deformable) facets through a novel nonlinear mechanics model. The nonlinearity presents challenges for finding the optimal design, and we employ an evolutionary algorithm for navigating this complex design space. With this framework, fold patterns satisfying targeted motions can be identified automatically and thus enables discovery of fold patterns designed specifically for engineering applications.
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Automated Design of Energy Efficient Control Strategies for building clusters using reinforcement learning
Philip Odonkor; Kemper Lewis
J. Mech. Des. 2018; 141(2):021704-021704-9.
From smartphones to electric cars, lithium-ion batteries allow us power our favorite devices. When used in our homes, they allow us to store cheap electricity for later use. These batteries, however, can be prohibitively expensive. But what if a single battery can intelligently be shared by multiple homes? In this paper, we demonstrate the feasibility of this idea by developing an algorithm to autonomously learn the consumption behaviors of multiple real-world homes. This insight is leveraged to produce use strategies, allowing multiple homes to simultaneously enjoy the benefits of a single battery system.
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Carlye A. Lauff; Daria Kotys-Schwartz; Mark E. Rentschler
J. Mech. Des. 2018; 140(6):061102-061102-12; doi: 10.1115/1.4039340
Prototyping is an essential part of a company’s product development process. It is critical to launching new products to market; these products can range from the next generation iPhone to surgical devices for doctors to your favorite shoes. Currently, there are limited research studies conducted within companies, meaning we lack an understanding about how companies engage in prototyping activities. This research project observed the entire product development process within three companies in the fields of consumer electronics, medical devices, and footwear. Through our analysis, we uncovered that prototypes are tools for enhanced communication, increased learning, and informed decision-making.
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An Integrated Type and Dimensional Synthesis Method to Design One Degree-of-Freedom Planar Linkages With Only Revolute Joints for Exoskeletons
Zefang Shen; Garry Allison; Lei Cui
J. Mech. Des. 2018; 140(9):092302-092302-12
Exoskeletons are wearable robots developed to assist the wear’s motion. In rehabilitation, such devices can help patients relearn natural motion after surgery, spinal cord injury, stroke, etc. Compared with conventional rehabilitation, exoskeleton-based rehabilitation can provide highly stable and repetitive movements. However most current devices are bulky and heavy, which limits their application in clinical settings. In this paper, we propose a method to design compact and lightweight planar linkages for exoskeletons with multiple output joints, while requiring only one actuator. Candidate linkages are generated and then evaluated to obtain the optimal design of the linkages. Applying this method, we have developed an index finger exoskeleton and a leg exoskeleton for rehabilitation, both of which are compact and portable. Their simplicity in design also increase the affordability for exoskeleton devices, which can facilitate applications outside clinical settings.
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Dielectric elastomers (DEs) may be a more energy efficient, lightweight, and low-cost solution for many emerging mechatronics applications when compared against established actuation technologies (e.g. solenoids or pneumatic cylinders). DE actuators (DEA) are also highly scalable, have low power consumption, and offer high flexibility. The presented work proposes a systematic tool for quasi-static performance prediction of circular out-of-plane DEAs. The method is based on extracting material characteristics (in terms of a stress-strain behavior) from a set of training data. This is then used to calculate the force-displacement characteristic for arbitrary geometries. The method is validated using two different prediction scenarios: blocking force and stroke of various geometries. The prediction errors for stroke and blocking force are not larger than 8.3% and 3.1%, respectively. Additionally, this work demonstrates that the stroke output mainly depends on the electrode ring width, and that it increases linearly. Also, it is shown that the force scales linearly with the average electrode ring circumference. These two parameters can be individually used to tailor DEA stroke and force output. The proposed method can then be used by designers to adopt DEAs for certain applications without the need for complicated FE models or prototyping.
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This section includes brief descriptions of articles soon to be or recently published by the Journal of Mechanical Design. These featured articles highlight recent research developments and emerging trends in mechanical design. For Abstracts and Full Articles please see ASME's Digital Collection.