Accepted Manuscripts

Mario Petrovic, Tsuyoshi Nomura, Takayuki Yamada, Kazuhiro Izui and Shinji Nishiwaki
J. Mech. Des   doi: 10.1115/1.4041220
In this paper, the application of orthotropic material orientation optimization for controlling heat flow in electric car power trains is presented. The design process is applied to a case model which conducts heat while storing heat-sensitive electronic components. The core of the case is designed using a low thermal conductivity material on order to focus the heat flow into the surface layer which is design a high thermal conductivity material. Material orthotropy is achieved in the surface layer of the case by removing the material at points determined by the optimization analysis. For this purpose, an orthotropic material orientation optimization method was extended to calculate optimal material distribution. This is achieved by transforming the initially obtained optimal orientation vector field into a scalar field through the use of coupled time dependent non-isotropic Helmholtz equations. Multiple parameters allow the control of the scalar field, indicating the distribution of the orthotropic material, in order to improve manufacturability. The analysis method is applied to divert heat flow from a specific section of the model while focusing the heat flow to another section. The results are shown for a model with a 0.1[mm] thick surface layer of copper and are compared to several other materials and layer thicknesses. Finally, the manufactured design is presented.
TOPICS: Design, Optimization, Electric vehicles, Trains, Heat, Flow (Dynamics), Scalar field theory, Thermal conductivity, Copper, Electronic components
Design Innovation Paper  
Genliang Chen, Jiepeng Wang and Hao Wang
J. Mech. Des   doi: 10.1115/1.4041221
Benefiting from small incisions, reduced infection risks, less pain and fast recovery, minimally invasive surgery has shown tremendous advantages for patients. In such kinds of procedures, the remote center-of-motion (RCM) mechanisms play an important role in performing operation through small incisions. Inspired by the Peaucellier-Lipkin straight-line cell, this paper presents the design and verification of a new type of planar two degree-of-freedom (DOF) RCM mechanisms. The synthesized planar RCM mechanisms are realized by symmetric linkages actuated by two virtual center-of-motion (VCM) generators. The main merit of the proposed 2-DOF RCM mechanisms is the easiness in kinematics which results in a simple control theme. One of the candidate mechanisms, which is simple in structure and easy to fabricate, is intensively studied. A prototype was built, on which preliminary experiments have been conducted, to verify the feasibility of the proposed new design. And the experimental results show that, the kinematics of the fabricated 2-DOF prototype possesses relatively high RCM characteristics. Therefore, it is potentially applicable in robot-assisted minimally invasive surgeries.
TOPICS: Linkages, Kinematics, Design, Surgery, Engineering prototypes, Generators, Robots, Degrees of freedom
Hailin Huang, Bing Li, Tieshan Zhang, Zhao Zhang, Xiaozhi Qi and Ying Hu
J. Mech. Des   doi: 10.1115/1.4041178
This paper presents the design methodology for a single-mobility, large surface-deployable mechanism using irregularly shaped triangular prismoid units. First, we demonstrate that the spherical shell, as the profile of the large deployable mechanism, cannot be filled with identical regular-shaped triangular prismoids (truncated pyramid) without gaps, which makes the design challenging because a large set of nonidentical modules should be moved synchronously. Second, we discuss the design of a novel deployable mechanism that can be deployed onto irregularly shaped triangular prismoids, which will be used as the basic module to fill the spherical shell. Owing to high stiffness and ease of actuation, a planar scissor-shape deployable mechanism is applied. Third, we study the mobile assemblies of irregularly shaped modules in large surface-deployable mechanisms. We discover that hyper kinematic redundant constraints exist in a multiloop mechanism, making the design even more difficult. In order to address this issue, a methodology for reducing these redundant constraints is also discussed. Finally, a physical prototype is fabricated to demonstrate the feasibility of the proposed design methodology.
TOPICS: Design, Mechanical admittance, Spherical shells, Design methodology, Shapes, Kinematics, Engineering prototypes, Stiffness
Andrea Mazzurco, Jon Leydens and Brent K. Jesiek
J. Mech. Des   doi: 10.1115/1.4041171
The complexity of design for development (D4D), humanitarian engineering (HE), and similar projects emerges from multiple sources, including the overarching requirement to address complex sociotechnical problems by effectively engaging community members. However, missing from the literature on enacting D4D/HE projects is a clear framework that classifies extant community participation methods based on key characteristics, especially vis-à-vis level of community participation in problem definition and solution processes. To address this lack of extant frameworks, we first conducted a systematized literature search to identify methods used in D4D/HE projects. This literature search resulted in 64 identified methods. Following an iterative and systematic process to develop classification systems combined with content analysis, a bi-dimensional framework emerged to classify the methods. The first dimension of the framework organizes methods according to a spectrum of three levels of community engagement: 1) passive, 2) consultative, and 3) co-constructive. The second dimension classifies methods based on the part of the design process in which it is most appropriate to use them. We conclude the paper by discussing considerations engineers should reflect upon when using the framework to inform their projects, as well as opportunities for future research.
TOPICS: Design, Dimensions, Engineers, Classification
Khaldon Meselhy and Gary Wang
J. Mech. Des   doi: 10.1115/1.4041172
Reliability based design optimization (RBDO) algorithms typically assume designer's prior knowledge of the objective function along with its explicit mathematical formula and the probability distributions of random decision variables. These assumptions may not be valid in many industrial cases where there is limited information on variable variability and the objective function is subjective and without mathematical formula. A new methodology is developed in this research to model and solve this type of problems with qualitative objective functions and limited information of random variables. Causal graphs and design structure matrix are used to capture designer's qualitative knowledge of effects of decision variables on the objective. Maximum entropy theory and Mont Carlo simulation are used to model random variables variability and derive reliability constraint functions. A new deterministic meta-optimization problem is formulated which is characterized by an optimum design point located close to the original problem optimum. The developed algorithm is tested and validated using Golinski speed reducer case study. The results show that the algorithm finds a near optimal reliable design with less initial information and less computation effort as compared to other RBDO algorithms that assume full knowledge.
TOPICS: Reliability-based optimization, Algorithms, Design, Optimization, Computation, Statistical distributions, Reliability, Simulation, Entropy
Elizabeth Starkey, Samuel Hunter and Scarlett Miller
J. Mech. Des   doi: 10.1115/1.4041173
The purpose of product dissection is to teach students how a product works and provide them with inspiration for new ideas. However, little is known about how variations in dissection activities impact creative outcomes or engineering (ESE) and creative self-efficacies (CSE). This is important since the goal of engineering education is to produce capable and creative engineers. The current study was thus developed to address this research gap through a factorial experiment. The results showed that idea development was not impacted by dissection conditions but that ESE and CSE were increased through these activities. The results also showed that higher levels of CSE and ESE had alternate effects on novel idea development indicating they are at odds in engineering education.
TOPICS: Creativity, Engineering education, Students, Performance, Engineers
Yoshihiro Kanno
J. Mech. Des   doi: 10.1115/1.4041174
This paper presents a simple and effective heuristic for topology optimization of a truss under the constraint that all the members of the truss have the common cross-sectional area. The proposed method consists of multiple restarts of the alternating direction method of multipliers (ADMM) with random initial points. It is shown that each iteration of the ADMM can be carried out very easily. In the numerical experiments, the efficiency of the proposed heuristic is compared with the existing global optimization method based on the mixed-integer second-order cone programming. It is shown that, even for large-scale problem instances that the global optimization method cannot solve within practically acceptable computational cost, the proposed method can often find a feasible solution having a fairly good objective value within moderate computational time.
TOPICS: Trusses (Building), Cross section (Physics), Optimization, Topology, Computer programming
Arnoud Delissen, Giuseppe Radaelli, Lucas Shaw, Jonathan Hopkins and Just L. Herder
J. Mech. Des   doi: 10.1115/1.4041170
A great deal of engineering effort is focused on changing mechanical material properties by creating micro-structural architectures instead of modifying chemical composition. This results in meta-materials, which can exhibit properties not found in natural materials and can be tuned to the needs of the user. To change the Poisson's ratio and Young's modulus, many current designs exploit mechanisms and hinges to obtain the desired behavior. However, this can lead to non-linear material properties and anisotropy, especially for large strains. In this work, we propose a new material design that makes use of curved leaf springs in a planar lattice. First, analytical ideal springs are employed to establish sufficient conditions for linear elasticity, isotropy, and a zero Poisson's ratio. Additionally, the Young's modulus is directly related to the spring stiffness. Secondly, a design method from literature is employed to obtain a spring, closely matching the desired properties. Next, numerical simulations of larger lattices show that the expectations hold, and a feasible material design is presented with an in-plane Young's modulus error of only 2% and a Poisson's ratio of 2.78·10^-3. These properties are isotropic and linear up to compressive and tensile strains of 0.12. The manufacturability and validity of the numerical model is shown by a prototype.
TOPICS: Deformation, Poisson ratio, Design, Metamaterials, Stiffness, Springs, Young's modulus, Materials properties, Computer simulation, Hinges, Anisotropy, Elasticity, Engineering prototypes, Design methodology, Architecture, Errors, Isotropy
Yingjun Wang, Sajad Arabnejad Khanoki, Michael Tanzer and Damiano Pasini
J. Mech. Des   doi: 10.1115/1.4041208
Even in a well-functioning total hip replacement, significant peri-implant bone resorption can occur secondary to stress shielding. Stress shielding is caused by an undesired mismatch of elastic modulus between the stiffer implant and the adjacent bone tissue. To address this problem, we present here a microarchitected hip implant that consists of a three-dimensional graded lattice material with properties that are mechanically biocompatible with those of the femoral bone. Asymptotic homogenization is used to numerically determine the mechanical and fatigue properties of the implant, and a non-gradient scheme of topology optimization is used to find the optimized relative density distribution of the porous implant under multiple constraints dictated by implant micromotion, pore size, porosity, and minimum manufacturable thickness of the cell elements. Obtained for a 38-year-old patient femur, bone resorption is assessed for postoperative conditions. The numerical results suggest that bone loss for the optimized implant is only 42% of that of a fully solid implant, here taken as benchmark, and 79% of that of a porous implant with uniform density. The architected hip implant presented in this work shows clinical promise in reducing bone loss while preventing implant micromotion, thereby contributing to reduce the risk of periprosthetic fracture and the probability of revision surgery.
TOPICS: Design, Density, Hip joint prostheses, Bone, Stress, Fracture (Materials), Risk, Fracture (Process), Optimization, Surgery, Elastic moduli, Porosity, Probability, Topology, Biocompatibility, Fatigue properties
Zongliang Du, Xiao-Yi Zhou, Renato Picelli and Hyunsun Alicia Kim
J. Mech. Des   doi: 10.1115/1.4041176
With the rapid developments of advanced manufacturing and its ability to manufacture microscale features, architected materials are receiving ever increasing attention in many physics fields. Such a design problem can be treated in topology optimization as architected material with repeated unit cells using the homogenization theory with the periodic boundary condition. When multiple architected materials with spatial variations in a structure are considered, a challenge arises in topological solutions which may not be connected between adjacent material architecture. This paper introduces a new measure, Connectivity Index (CI) to quantify the topological connectivity and adds it as a constraint in multiscale topology optimization to achieve connected architected materials. Numerical investigations reveal that the additional constraints lead to microstructural topologies which are well connected and do not substantially compromise their optimalities.
TOPICS: Optimization, Topology, Boundary-value problems, Physics, Manufacturing, Design, Microscale devices
Review Article  
Raymundo Arroyave, Samantha Shields, Chi-Ning Chang, Debra Fowler, Richard Malak and Douglas Allaire
J. Mech. Des   doi: 10.1115/1.4041177
We present here the results from a workshop on interdisciplinary research on design of engineering material systems, sponsored by the National Science Foundation. The workshop was prompted by the need to foster a culture of interdisciplinary collaboration between the engineering design and materials communities. The workshop addressed: (i) conceptual barriers between materials and engineering design research communities; (ii) research questions that the interdisciplinary field of materials design should focus on; (iii) processes and metrics to be used to validate research activities and outcomes on materials design; (iv) strategies to sustain and grow the interdisciplinary field. This contribution presents a summary of the state of the field---elicited through extensive guided discussions between representatives of both communities---and a snapshot of research activities that have emerged since the workshop. Based on the increasing level of sophistication of interdisciplinary research programs on design of materials it is apparent that the field is growing and has great potential to play a key role in a vibrant interdisciplinary materials innovation ecosystem. Sustaining such efforts will contribute significantly to the advancement of technologies that will impact many industries and will enhance society-wide health, security and economic well-being.
TOPICS: Design, Workshops (Work spaces), Engineering design, Performance, Collaboration, Innovation, Security
Design Innovation Paper  
Joaquim Manoel Justino Netto and Zilda de Castro Silveira
J. Mech. Des   doi: 10.1115/1.4041175
This paper presents the embodiment design of an interchangeable print head based on twin-screw extrusion, specially developed to allow in-process multi-material mixing and direct deposition of the product to structure three-dimensional parts. The print head focus on research applications with middle-end 3D printers. Commercial extrusion-based 3D printers have limited applicability due to the scarce variety of plastic filaments available. In that context, one important trend for the advance of additive manufacturing is the design of systems capable of using alternative material types in different states. The systematic process is presented as a case study and brings together concepts from mechanical design and polymer processing. The main contribution of this paper is to provide general guidelines to be used on similar projects, in view of the crescent demand for more adequate and flexible additive processes.
TOPICS: Screws, Extruding, Design, Additive manufacturing, Design engineering, Polymers
Alexandra Bloesch-Paidosh and Kristina Shea
J. Mech. Des   doi: 10.1115/1.4041051
Additive manufacturing (AM) has unique capabilities when compared to traditional manufacturing, such as shape, hierarchical, functional, and material complexity, a fact that has fascinated those in research, industry, and the media for the last decade. Consequently, designers would like to know how they can incorporate AM's special capabilities into their designs, but are often at a loss as how to do so. Design for Additive Manufacturing (DfAM) methods are currently in development but the vast majority of existing methods are not tailored to the needs and knowledge of designers in the early stages of the design process. Therefore, we propose a set of process-independent design heuristics for AM aimed at transferring the high-level knowledge necessary for reasoning about functions, configurations, and parts to designers. Twenty-nine design heuristics for AM are derived from 275 AM artifacts. An experiment is designed to test their efficacy in the context of a re-design scenario with novice designers. The heuristics are found to positively influence the designs generated by the novice designers and are found to be more effective at communicating DfAM concepts in the early phases of re-design than a lecture on DfAM alone. Future research is planned to validate the impact with expert designers and in original design scenarios.
TOPICS: Design, Additive manufacturing, Manufacturing, Shapes
Anand Balu Nellippallil, Vignesh Rangaraj, BP Gautham, Amarendra Singh, Janet K. Allen and Farrokh Mistree
J. Mech. Des   doi: 10.1115/1.4041050
A materials design revolution is underway with a focus to design the material microstructure and processing paths to achieve certain performance requirements of products. A host of manufacturing processes are involved in producing a product. The processing carried out in each process influences its final properties. To couple the material processing-structure-property-performance spaces, models of specific manufacturing processes must be enhanced and integrated using multiscale modeling techniques (vertical integration) and then the input and output of the various manufacturing processes must be integrated to facilitate the flow of information from one process to another (horizontal integration). Together vertical and horizontal integration allows for the inverse decision-based design exploration of the manufacturing process chain in order to realize the end product. In this paper, we present an inverse decision-based design method to achieve the integrated design exploration of materials, products and manufacturing processes through the vertical and horizontal integration of models. The method is supported by the Concept Exploration Framework to systematically explore design alternatives and generate satisficing design solutions. The efficacy of the method is illustrated for a hot rod rolling and cooling process chain problem by exploring the processing paths and microstructure in an inverse manner to produce a rod with specific mechanical properties. The proposed method and the exploration framework are generic and support the integrated decision-based design exploration of a process chain to realize an end product by tailoring material microstructures and processing paths.
TOPICS: Manufacturing, Design, Design methodology, Chain, Multiscale modeling, Space, Mechanical properties, Flow (Dynamics), Cooling
Weisheng Zhang, Ying Liu, Zongliang Du, Yichao Zhu and Xu Guo
J. Mech. Des   doi: 10.1115/1.4041052
Stiffened structures are widely used in industry. However, how to optimally distribute the stiffening ribs on a given base plate remains a challenging issue, partially because the topology and geometry of stiffening ribs are often represented in a geometrically implicit way in traditional approaches. This implicit treatment may lead to problems such as high computational cost (caused by the large number of design variables, geometry constraints in optimization and large degrees of freedom (DOF) in finite element analysis (FEA)) and the issue of manufacturability. This paper presents a Moving Morphable Component (MMC)-based approach for topology optimization of rib-stiffened structures, where the topology and geometry of stiffening ribs are explicitly described. The proposed approach displays several prominent advantages, such as, 1) both the numbers of design variables and DOF in FEA are reduced substantially; 2) the proper manufacture-related geometry requirements of stiffening ribs can be readily satisfied without introducing any additional constraint. The effectiveness of the proposed approach is further demonstrated with numerical examples on topology optimization of rib-stiffened structures with buckling constraints.
TOPICS: Optimization, Buckling, Topology, Geometry, Finite element analysis, Design, Degrees of freedom
Chengjie Rui, Haitao Li, Jie Yang, Wenjun Wei and Xuezhu Dong
J. Mech. Des   doi: 10.1115/1.4041053
Land width and relief angle of a dual-cone double enveloping hourglass worm gear hob are two factors which influence the life and the hobbing performance of the hob. Both of them are obtained after generating relief surfaces. Due to the reason that the teeth of this type hob have different profiles with each other, the relief surface is difficult to generate for keeping all cutting teeth with uniformed relief angle and uniformed land width. For the purpose that land width and relief angle could be machined precisely, a design and generating method for grinding relief surfaces is put forward in this paper. A double cone-grinding wheel is used to generate the relief surface. Based on the theory of gearing and generating, the mathematical model for grinding relief surfaces of a hob is built. The motion parameters when grinding different points of land edges of different hob teeth are solved out. A generating simulation is built by putting those motion parameters data into a four-axis hourglass worm-grinding machine. The results of the simulation show that the relief surfaces of the hob can be ground continuously, and the land width and the relief angle are meeting the requirements.
TOPICS: Grinding, Worm gears, Design, Simulation, Machinery, Cutting, Wheels
Prabhat Kumar, Anupam Saxena and Roger Sauer
J. Mech. Des   doi: 10.1115/1.4041054
Topologies of large deformation Contact-aided Compliant Mechanisms (CCMs), with self and mutual contact, exemplified via path generation applications, are designed using the continuum synthesis approach. Design domains are parameterized using honeycomb tessellation. Assignment of material to each cell, and generation of rigid contact surfaces, are accomplished via suitably sizing and positioning negative circular masks. To facilitate contact analysis, boundary smoothing is implemented. Mean value coordinates are employed to compute shape functions, as many regular hexagonal cells get degenerated into irregular, concave polygons as a consequence of boundary smoothing. Both, geometric and material nonlinearities are considered in the finite element analysis. The augmented Lagrange multiplier method in association with an active set strategy is employed to incorporate both self and mutual contact. CCMs are evolved using the stochastic hill climber search. Synthesized contact-aided compliant continua trace paths with single and importantly, multiple kinks and experience multiple contact interactions pertaining to both self and mutual contact modes.
TOPICS: Deformation, Compliant mechanisms, Honeycomb structures, Design, Finite element analysis, Shapes
Seyede Fatemeh Ghoreishi, Abhilash Molkeri, Ankit Srivastava, Raymundo Arroyave and Douglas Allaire
J. Mech. Des   doi: 10.1115/1.4041034
Integrated Computational Materials Engineering (ICME) calls for the integration of computational tools into the materials and parts development cycle, while the Materials Genome Initiative (MGI) calls for the acceleration of the materials development cycle through the combination of experiments, simulation, and data. As they stand, both ICME and MGI do not prescribe how to achieve the necessary tool integration or how to efficiently exploit the computational tools, in combination with experiments, to accelerate the development of new materials and materials systems. This paper addresses the first issue by putting forward a framework for the fusion of information that exploits correlations among sources/models and between the sources and `ground truth'. The second issue is addressed through a multi-information source optimization framework that identifies, given current knowledge, the next best information source to query and where in the input space to query it via a novel value-gradient policy. The querying decision takes into account the ability to learn correlations between information sources, the resource cost of querying an information source, and what a query is expected to provide in terms of improvement over the current state. The framework is demonstrated on the optimization of a dual-phase steel to maximize its strength-normalized strain hardening rate. The ground truth is represented by a microstructure-based finite element model while three low fidelity information sources---i.e. reduced order models---based on different homogenization assumptions---isostrain, isostress and isowork---are used to efficiently and optimally query the materials design space.
TOPICS: Optimization, Cycles, Finite element model, Work hardening, Materials science, Steel, Simulation, Design
Mingyang Li and Zequn Wang
J. Mech. Des   doi: 10.1115/1.4040985
To reduce the computational cost, surrogate models have been widely used to replace the expensive simulations in design under uncertainty. However, most existing methods may introduce significant errors when the training data is limited. This paper presents a confidence-driven design optimization (CDDO) framework to manage surrogate model uncertainty for probabilistic design optimization. In this study, a confidence-based Gaussian process modeling technique is developed to compensate the surrogate model uncertainty in system performance prediction by taking both the prediction mean and variance into account. With a user defined confidence level, a conservative system reliability can be obtained based on the confidence-based GP models in Monte Carlo simulation (MCS). In addition, a new sensitivity analysis method is proposed to incorporate the surrogate model uncertainty in approximating the sensitivity of the conservative reliability with respect to design variables without extra computational cost. Two case studies are introduced to demonstrate the effectiveness of the proposed approach.
TOPICS: Design, Optimization, Uncertainty, Reliability, Simulation, Modeling, Design under uncertainty, Errors, Sensitivity analysis
Junqi Yang, Hongyi Xu, Zhenfei Zhan and Ching-hung Chuang
J. Mech. Des   doi: 10.1115/1.4040984
Design optimization of composite structures is more challenging than design optimization of metal structures due to the larger dimensionality of the design space. In addition to the geometric variables (e.g. thickness of each component), the composite layup (the fiber orientation of each layer) also needs to be considered as design variables in optimization. However, the existing optimization methods are inefficient when applied to the multi-component, multi-layer composite structures. The low efficiency is caused by the high dimensionality of the design space and the inherent shortcomings in the existing design representation methods. In this work, two existing composite layup representation methods are investigated to identify the root cause of the low efficiency. Furthermore, a new Structural Equation Modeling (SEM)-based strategy is proposed to reduce the dimensionality of the design space. This strategy also helps the designers to identify the loading mode of each component of the structure system. This strategy is tested in two scenarios of engineering optimization: (1) the direct multidisciplinary design optimization (DMDO), and (2) the metamodeling-based optimization. The proposed methods are compared with the traditional methods on three benchmark studies, which include one nonlinear mathematical example and two engineering design problems. It is observed that the design representation methods have a strong impact on the optimization results. The three case studies also demonstrate the effectiveness of the proposed strategy. Furthermore, recommendations are made on the selection of optimization methods for the design of composite structures.
TOPICS: Composite materials, Design, Modeling, Optimization, Fibers, Metalwork, Engineering design

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