Design of Kinematic Connectors for Microstructured Materials Produced by Additive Manufacturing
The main characteristic of materials with a functional gradient is the progressive composition or the structure variation across its geometry. This results in the properties variation in one or more specific directions, according to the functional application requirements. Cellular structure flexibi...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-05-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/13/9/1500 |
| _version_ | 1797535102161387520 |
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| author | Miguel R. Silva João A. Dias-de-Oliveira António M. Pereira Nuno M. Alves Álvaro M. Sampaio António J. Pontes |
| author_facet | Miguel R. Silva João A. Dias-de-Oliveira António M. Pereira Nuno M. Alves Álvaro M. Sampaio António J. Pontes |
| author_sort | Miguel R. Silva |
| collection | DOAJ |
| description | The main characteristic of materials with a functional gradient is the progressive composition or the structure variation across its geometry. This results in the properties variation in one or more specific directions, according to the functional application requirements. Cellular structure flexibility in tailoring properties is employed frequently to design functionally-graded materials. Topology optimisation methods are powerful tools to functionally graded materials design with cellular structure geometry, although continuity between adjacent unit-cells in gradient directions remains a restriction. It is mandatory to attain a manufacturable part to guarantee the connectedness between adjoining microstructures, namely by ensuring that the solid regions on the microstructure’s borders i.e., kinematic connectors) match the neighboring cells that share the same boundary. This study assesses the kinematic connectors generated by imposing local density restrictions in the initial design domain (i.e., nucleation) between topologically optimised representative unit-cells. Several kinematic connector examples are presented for two representatives unit-cells topology optimised for maximum bulk and shear moduli with different volume fractions restrictions and graduated Young’s modulus. Experimental mechanical tests (compression) were performed, and comparison studies were carried out between experimental and numerical Young’s modulus. The results for the single maximum bulk for the mean values for experimental compressive Young’s modulus (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>) with 60<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>%</mo><mspace width="3.33333pt"></mspace><msub><mi>V</mi><mi mathvariant="normal">f</mi></msub></mrow></semantics></math></inline-formula> show a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>9.15</mn><mo>%</mo></mrow></semantics></math></inline-formula>. The single maximum shear for the experimental compressive Young’s modulus mean values (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>) with 60<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>%</mo><mspace width="3.33333pt"></mspace><msub><mi>V</mi><mi mathvariant="normal">f</mi></msub></mrow></semantics></math></inline-formula>, exhibit a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>11.73</mn><mo>%</mo></mrow></semantics></math></inline-formula>. For graded structures, the experimental mean values of compressive Young’s moduli (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>), compared with predicted total Young’s moduli (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mi>Se</mi></msup></semantics></math></inline-formula>), show a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>6.96</mn></mrow></semantics></math></inline-formula> for the bulk graded structure. The main results show that the single type representative unit-cell experimental Young’s modulus with higher volume fraction presents a minor deviation compared with homogenized data. Both (i.e., bulk and shear moduli) graded microstructures show continuity between adjacent cells. The proposed method proved to be suitable for generating kinematic connections for the design of shear and bulk graduated microstructured materials. |
| first_indexed | 2024-03-10T11:39:30Z |
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| institution | Directory Open Access Journal |
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| last_indexed | 2024-03-10T11:39:30Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
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| series | Polymers |
| spelling | doaj.art-bb126043009b445a9181067f7f0487312023-11-21T18:37:07ZengMDPI AGPolymers2073-43602021-05-01139150010.3390/polym13091500Design of Kinematic Connectors for Microstructured Materials Produced by Additive ManufacturingMiguel R. Silva0João A. Dias-de-Oliveira1António M. Pereira2Nuno M. Alves3Álvaro M. Sampaio4António J. Pontes5CDRSP, ESTG, Polytechnic of Leiria, 2401-951 Leiria, PortugalDepartment of Mechanical Engineering, TEMA/Centre for Mechanical Technology and Automation, University of Aveiro, 3810-193 Aveiro, PortugalCDRSP, ESTG, Polytechnic of Leiria, 2401-951 Leiria, PortugalCDRSP, ESTG, Polytechnic of Leiria, 2401-951 Leiria, PortugalInstitute for Polymers and Composites—IPC, School of Engineering, University of Minho, 4800-058 Guimarães, PortugalInstitute for Polymers and Composites—IPC, School of Engineering, University of Minho, 4800-058 Guimarães, PortugalThe main characteristic of materials with a functional gradient is the progressive composition or the structure variation across its geometry. This results in the properties variation in one or more specific directions, according to the functional application requirements. Cellular structure flexibility in tailoring properties is employed frequently to design functionally-graded materials. Topology optimisation methods are powerful tools to functionally graded materials design with cellular structure geometry, although continuity between adjacent unit-cells in gradient directions remains a restriction. It is mandatory to attain a manufacturable part to guarantee the connectedness between adjoining microstructures, namely by ensuring that the solid regions on the microstructure’s borders i.e., kinematic connectors) match the neighboring cells that share the same boundary. This study assesses the kinematic connectors generated by imposing local density restrictions in the initial design domain (i.e., nucleation) between topologically optimised representative unit-cells. Several kinematic connector examples are presented for two representatives unit-cells topology optimised for maximum bulk and shear moduli with different volume fractions restrictions and graduated Young’s modulus. Experimental mechanical tests (compression) were performed, and comparison studies were carried out between experimental and numerical Young’s modulus. The results for the single maximum bulk for the mean values for experimental compressive Young’s modulus (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>) with 60<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>%</mo><mspace width="3.33333pt"></mspace><msub><mi>V</mi><mi mathvariant="normal">f</mi></msub></mrow></semantics></math></inline-formula> show a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>9.15</mn><mo>%</mo></mrow></semantics></math></inline-formula>. The single maximum shear for the experimental compressive Young’s modulus mean values (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>) with 60<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>%</mo><mspace width="3.33333pt"></mspace><msub><mi>V</mi><mi mathvariant="normal">f</mi></msub></mrow></semantics></math></inline-formula>, exhibit a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>11.73</mn><mo>%</mo></mrow></semantics></math></inline-formula>. For graded structures, the experimental mean values of compressive Young’s moduli (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mover accent="true"><mi mathvariant="normal">x</mi><mo>¯</mo></mover></msup></semantics></math></inline-formula>), compared with predicted total Young’s moduli (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>E</mi><mi>Se</mi></msup></semantics></math></inline-formula>), show a deviation of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>6.96</mn></mrow></semantics></math></inline-formula> for the bulk graded structure. The main results show that the single type representative unit-cell experimental Young’s modulus with higher volume fraction presents a minor deviation compared with homogenized data. Both (i.e., bulk and shear moduli) graded microstructures show continuity between adjacent cells. The proposed method proved to be suitable for generating kinematic connections for the design of shear and bulk graduated microstructured materials.https://www.mdpi.com/2073-4360/13/9/1500kinematic connectorsfunctionally graded materialsmicrostructuredadditive manufacturingtopology optimisation |
| spellingShingle | Miguel R. Silva João A. Dias-de-Oliveira António M. Pereira Nuno M. Alves Álvaro M. Sampaio António J. Pontes Design of Kinematic Connectors for Microstructured Materials Produced by Additive Manufacturing Polymers kinematic connectors functionally graded materials microstructured additive manufacturing topology optimisation |
| title | Design of Kinematic Connectors for Microstructured Materials Produced by Additive Manufacturing |
| title_full | Design of Kinematic Connectors for Microstructured Materials Produced by Additive Manufacturing |
| title_fullStr | Design of Kinematic Connectors for Microstructured Materials Produced by Additive Manufacturing |
| title_full_unstemmed | Design of Kinematic Connectors for Microstructured Materials Produced by Additive Manufacturing |
| title_short | Design of Kinematic Connectors for Microstructured Materials Produced by Additive Manufacturing |
| title_sort | design of kinematic connectors for microstructured materials produced by additive manufacturing |
| topic | kinematic connectors functionally graded materials microstructured additive manufacturing topology optimisation |
| url | https://www.mdpi.com/2073-4360/13/9/1500 |
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