Modeling of the Interface of Functionally Graded Superelastic Zones in Compliant Deployable Structures

2018 ◽  
Author(s):  
Jovana Jovanova ◽  
Simona Domazetovska ◽  
Mary Frecker
Keyword(s):  
Compliant Mechanisms ◽  
Step Change ◽  
Functionally Graded ◽  
Deployable Structures ◽  
Additive Manufacturing Technology ◽  
Compositional Gradients ◽  
Local Compliance ◽  
Transformation Stress ◽  
Gradient Change ◽  
Compact Shape

Functionally graded compliant mechanisms can be fabricated with additive manufacturing technology by engineering the microstructural and compositional gradients at selected locations resulting in compositionally graded zones of higher and lower flexibility. The local compliance depends on the geometry of the structure as well as the material property in the selected region. As Nitinol (NiTi) is well suited for applications requiring compliance, the critical transformation stress and the superelastic modulus of elasticity are crucial parameters for defining the local compliance. To understand the behavior at the interface between two different material compositions, three models of gradient change between the alloys are analyzed: step change, linear and polynomial gradients. In addition to localize the deformation in the interface, three different flexure designs in the interface are analyzed. This paper will address a methodology for modeling and parametrization of material properties and transition at the interface, for different flexure designs. The combined effort in the interface of the functional grading and the geometry will be used for the design of monolithic self-deployable structures, initially folded in compact shape. The design motivation comes from the self-deploying mechanisms inspired by insects’ wings.

BI-STABLE ANALYSES OF LAMINATED FGM SHELLS

2012 ◽  
Vol 12 (02) ◽  
pp. 311-335 ◽  
Author(s):  
X. Q. HE ◽  
L. LI ◽  
S. KITIPORNCHAI ◽  
C. M. WANG ◽  
H. P. ZHU
Keyword(s):  
Power Law ◽  
Functionally Graded Material ◽  
Volume Fraction ◽  
Functionally Graded ◽  
Optimum Combination ◽  
Thickness Direction ◽  
Power Law Distribution ◽  
Deployable Structures ◽  
Graded Material ◽  
Two Parameter

Based on an inextensional two-parameter analytical model for cylindrical shells, bi-stable analyses were carried out on laminated functionally graded material (FGM) shells with various layups of fibers. Properties of FGM shells are functionally graded in the thickness direction according to a volume fraction power law distribution. The effects of constituent volume fractions of FGM matrix are examined on the curvature and twist of laminated FGM shells. The results reveal that the optimum combination of constituents of FGM matrix can be obtained for the maximum twist of FGM shells with antisymmetric layups, which helps the design of deployable structures. The effects of Young's modulus of fibers and the symmetry of layups on bi-stable behaviors are also discussed in detail.

Two Stage Design of Compliant Mechanisms With Superelastic Compliant Joints

2017 ◽  
Author(s):  
Jovana Jovanova ◽  
Mary Frecker
Keyword(s):  
Analytical Model ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Functionally Graded ◽  
Two Stage ◽  
Stage Design ◽  
Rigid Link ◽  
Starting Point ◽  
Single Piece ◽  
Two Stage Design

The design of compliant mechanisms made of Nickel Titanium (NiTi) Shape Memory Alloys (SMAs) is considered to exploit the superelastic behavior of the material to achieve tailored high flexibility on demand. This paper focuses on two-stage design optimization of compliant mechanisms, as a systematic method for design of the composition of the functionally graded NiTi material within the compliant mechanism devices. The location, as well as geometric and mechanical properties, of zones of high and low flexibility will be selected to maximize mechanical performance. The proposed two-stage optimization procedure combines the optimization of an analytical model of a single-piece functionally graded unit, with a detailed FEA of a continuous compliant mechanism. In the first stage, a rigid-link model is developed to initially approximate the behavior of the compliant mechanism. In the second stage the solution of the rigid-link problem serves as the starting point for a continuous analytical model where the mechanism consists of zones with different material properties and geometry, followed by a detailed FEA of a compliant mechanism with integrated zones of superelasticity. The two-stage optimization is a systematic approach for compliant mechanism design with functional grading of the material to exploit superelastic response in controlled manner. Direct energy deposition, as an additive manufacturing technology, is foreseen to fabricate assemblies with multiple single piece functional graded components. This method could be applied to bio-inspired structures, flapping wings, flexible adaptive structures and origami inspired compliant mechanisms.

Origami Kaleidocycle-Inspired Symmetric Multistable Compliant Mechanisms

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongchuan Zhang ◽  
Benliang Zhu ◽  
Xianmin Zhang
Keyword(s):  
Arbitrary Number ◽  
Compliant Mechanisms ◽  
Rotation Angle ◽  
Screw Theory ◽  
Compliant Mechanism ◽  
Mobility Analysis ◽  
Stable States ◽  
Deployable Structures ◽  
Basic Dimension ◽  
Metamorphic Robots

Compliant kaleidocycles can be widely used in a variety of applications, including deployable structures, origami structures, and metamorphic robots, due to their unique features of continuous rotatability and multistability. Inspired by origami kaleidocycles, a type of symmetric multistable compliant mechanism with an arbitrary number of units is presented and analyzed in this paper. First, the basic dimension constraints are developed based on mobility analysis using screw theory. Second, the kinematic relationships of the actual rotation angle are obtained. Third, a method to determine the number of stabilities and the position of stable states, including the solution for the parameterized boundaries of stable regions, is developed. Finally, experimental platforms are established, and the validity of the proposed multistable mechanisms is verified.

scholarly journals Addition of Chromium and its effect on the microstructure and mechanical properties of laser-coated high carbon ferrochrome alloy on mild steel

2021 ◽  
Author(s):  
Basiru Philip Aramide ◽  
Patricia Popoola ◽  
Rotimi Sadiku ◽  
Tamba Jamiru ◽  
Sisa Pityana
Keyword(s):  
Functionally Graded ◽  
High Temperature Strength ◽  
High Carbon ◽  
Monolithic Material ◽  
Surface Strengthening ◽  
Additive Manufacturing Technology ◽  
Carbon Ferrochrome ◽  
Ferrochrome Alloy ◽  
Graded Material ◽  
Better Than

Abstract Laser cladding is an additive manufacturing technology that can be utilized in surface strengthening, modification, and repair of components that are subjected to adverse working conditions. This can be accomplished by the addition of functionally graded material with a remarkable limit to enhancing an engaged credited property of monolithic material that is superior and better than its monolithic counterparts. Chromium addition to the microstructure of components has been found to increase the electrochemical stability, high-temperature strength and corrosion resistance of laser additive manufactured components. The current study investigates the effect of the extra addition of chromium on the hardness and microstructure of laser coated high carbon ferrochrome FeCrV15 on steel baseplate.

Functionally Graded Cellular Contact-Aided Compliant Mechanism for Energy Absorption

2018 ◽  
Author(s):  
Jovana Jovanova ◽  
Angela Nastevska ◽  
Mary Frecker
Keyword(s):  
Energy Absorption ◽  
Material Properties ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Functionally Graded ◽  
Nonlinear Material ◽  
Load Path ◽  
Cellular Contact ◽  
Overall Performance ◽  
Energy Absorbing

Cellular contact-aided compliant mechanisms (C3M) are cellular structures with integrated self-contact mechanisms, i.e. the segments can come into contact with each other during deformation. The contact changes the load path and can influence on the mechanism’s performance. Cellular contact-aided compliant mechanisms can be tailored for a specific structural application, such as energy absorption. Nickel Titanium compliant mechanisms can exploit the superelastic effect to improve performance and increase energy absorption. The potential for compliant mechanisms designed specifically for metal additive manufacturing opens the possibility of functional grading and tailoring the material properties locally for achieving overall performance. The combined effort of the geometry and the nonlinear material property increases the local compliance of the unit cell, resulting in higher energy absorption. A functionally graded 3D energy absorbing contact-aided compliant mechanisms cell with curved walls is analyzed. Functionally graded zones of higher flexibility are explored with different superelastic material properties. Introducing different moduli of elasticity as a function of the critical transformation stress results in different energy absorption. This approach can be used for tailoring the overall performance based on the application.

Target shape optimization of functionally graded shape memory alloy compliant mechanisms

2017 ◽  
Vol 30 (9) ◽  
pp. 1385-1396
Author(s):  
Jovana Jovanova ◽  
Mary Frecker ◽  
Reginald F Hamilton ◽  
Todd A Palmer
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Modulus Of Elasticity ◽  
Compliant Mechanisms ◽  
Material Model ◽  
Functionally Graded ◽  
Beam Model ◽  
Shape Error ◽  
Target Shape ◽  
Trade Offs

This article focuses on the design optimization of shape memory alloy compliant mechanisms with functionally graded properties to achieve a user-defined target shape. The functional grading is approximated by allowing the geometry and the modulus of elasticity of each zone to vary. The superelastic phenomenon has been taken into account using a standard nonlinear shape memory alloy material model with linear region of higher modulus of elasticity and a superelastic region with much lower modulus of elasticity. A large deflection beam model is integrated with a multi-objective evolutionary algorithm for constrained optimization of the structure’s mechanical properties and geometry. Examples illustrate the trade-offs between the objectives of minimizing shape error, maximum stress, and volume. It is observed that in the optimized designs, the elastic modulus and the geometry work together in regions where large flexibility is required to achieve the target shape.

Compact Directional and Frictional Hinges for Flat Folding Applications

2018 ◽  
Author(s):  
Patrick D. Shemenski ◽  
Brian P. Trease
Keyword(s):  
Complex Shape ◽  
Compliant Mechanisms ◽  
Deployable Structures ◽  
Packing Factor ◽  
Deployable Structure ◽  
The Creation

Thick-rigid deployable origami structures make use of compliant mechanisms to create folds and hinging surfaces. This paper examines the potential types of compact directional and frictional hinges to supplement the usage of compliant mechanisms in flat-folding applications. Rigid motioncontrolling hinges offer many opportunities to deployable origami. Hinges, in the form of hard stops, ratchets, or spring detents can allow for complex shape generation through kinematic manipulation. Hinged origami lends itself well to the creation of origami robotics, deployable structures, and arrays. With the ability to offer a high packing factor and create a self-supporting deployable structure, further research should be conducted into the application and development of hinged origami.

Large Deflection of Various Functionally Graded Beam Using Shooting Method

2011 ◽  
Vol 110-116 ◽  
pp. 4705-4711 ◽  
Author(s):  
Ali Soleimani
Keyword(s):  
Exact Solution ◽  
Elastic Modulus ◽  
Loading Condition ◽  
Shooting Method ◽  
Large Deflection ◽  
Compliant Mechanisms ◽  
Longitudinal Direction ◽  
Functionally Graded ◽  
Functionally Graded Beam ◽  
Arbitrary Loading

The equation of large deflection of functionally graded beam subjected to arbitrary loading condition is derived. In this work assumed that the elastic modulus varies by exponential and power function in longitudinal direction. The nonlinear derived equation has not exact solution so shooting method has been proposed to solve the nonlinear equation of large deflection. Results are validated with finite element solutions. The method will be useful toward the design of compliant mechanisms driven by smart actuators. Finally the effect of different elastic modulus functions and loading conditions are investigated and discussed.

scholarly journals Functionally Graded AISI 316L and AISI H13 Manufactured by L-DED for Die and Mould Applications

2021 ◽  
Vol 11 (2) ◽  
pp. 771
Author(s):  
Marta Ostolaza ◽  
Jon Iñaki Arrizubieta ◽  
Aitzol Lamikiz ◽  
Magdalena Cortina
Keyword(s):  
Functionally Graded ◽  
Added Value ◽  
Nonlinear Material ◽  
Aisi 316L ◽  
Premature Failure ◽  
Buffer Material ◽  
Graded Material ◽  
Aisi H13 ◽  
Compositional Gradients ◽  
Directed Energy

Tooling in the die and mould industry is subjected to high-wear and high-temperature environments, which often leads to the premature failure of this high-added-value tooling. When severe damage occurs, an alternative to replacing the whole component consists of the repair by laser-directed energy deposition (L-DED). For that end, intermediate layers are commonly employed as buffer material, where introducing a functionally graded material (FGM) might be beneficial to avoid material incompatibilities and improve the overall performance of the tooling. In the present work, an FGM composed of gradient AISI 316L to AISI H13 has been manufactured, and its microstructure and hardness analysed. Firstly, cracking owing to the formation of brittle intermediate phases has been detected. Secondly, an increase of the hardness and a decrease of the corrosion resistance has been observed when transitioning from AISI 316L to AISI H13. Thirdly, despite the FGM composition evolving linearly, nonlinear material properties such as hardness and corrosion have been observed, which are conditioned by the microstructure formed during the L‑DED process and the nonlinear influence of the composition of steel on such properties. Consequently, nonlinear compositional gradients are recommended if linear mechanical properties are to be obtained in the case of steel FGMs.

Sign in / Sign up

Export Citation Format

Share Document