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Liu Y, Wang Y, Deng Q. Radial Inertia Effect of Ultra-Soft Materials from Hopkinson Bar and Solution Methodologies. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3793. [PMID: 39124457 PMCID: PMC11313564 DOI: 10.3390/ma17153793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 07/25/2024] [Accepted: 07/30/2024] [Indexed: 08/12/2024]
Abstract
The split-Hopkinson pressure bar technique is widely used to determine the dynamic mechanical behavior of materials. However, spike-like stress features appear in the initial stress behavior of ultra-soft materials tested with a split-Hopkinson bar. These features are not intrinsic characteristics of the materials. Potential causes were investigated through experiments and numerical simulations. It was found that the spike feature represents derived stress resulting from the radial inertia effect during dynamic loading. In this work, we propose and experimentally verify effective methods to reduce this effect. The influences of density, strain acceleration, ratio between inner and outer diameter, and Poisson's ratio on the radial inertia effect were investigated. The spike stress was found to change linearly with density and strain acceleration but decrease significantly when the inner/outer diameter ratio was below 0.3, after which it remained nearly constant. A parabolic stress distribution was observed along the radial direction due to the Poisson effect, especially when the ratio exceeded 0.3, leading to higher spike stress. Finally, suggestions were proposed as experimental guidance when testing ultra-soft materials.
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Affiliation(s)
- Yue Liu
- Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
- Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
| | - Yongshuai Wang
- Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
- Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
| | - Qiong Deng
- Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
- Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application, School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
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2
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Cai Y, Binder WH. Triggered Crosslinking of Main-Chain Enediyne Polyurethanes via Bergman Cyclization. Macromol Rapid Commun 2023; 44:e2300440. [PMID: 37877520 DOI: 10.1002/marc.202300440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/23/2023] [Indexed: 10/26/2023]
Abstract
Crosslinking chemistries occupy an important position in polymer modification with a particular importance when triggered in response to external stimuli. Enediyne (EDY) moieties are used as functional entities in this work, known to undergo a pericyclic Bergman cyclization (BC) to induce a triggered crosslinking of polyurethanes (PU) via the intermediately formed diradicals. Diamino-EDYs, where the distance between the enyne-moieties is known to be critical to induce a BC, are placed repetitively as main-chain structural elements in isophorone-based PUs to induce reinforcement upon heating, compression, or stretching. A 7-day compression under room temperature results in a ≈69% activation of the BC, together with the observation of an increase in tensile strength by 62% after 25 stretching cycles. The occurrence of BC is further proven by the decreased exothermic values in differential scanning calorimetry, together with characteristic peaks of the formed benzene moieties via IR spectroscopy. Purely heat-induced crosslinking contributes to 191% of the maximum tensile strength in comparison to the virgin PU. The BC herein forms an excellent crosslinking strategy, triggered by heat or force in PU materials.
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Affiliation(s)
- Yue Cai
- Macromolecular Chemistry, Institute of Chemistry, Faculty of Natural Science II, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle (Saale), Germany
| | - Wolfgang H Binder
- Macromolecular Chemistry, Institute of Chemistry, Faculty of Natural Science II, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120, Halle (Saale), Germany
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Dong B, Du M, Fang H, Wang F, Zhang H, Zhu L. Compression-Softening Bond Model for Non-Water Reactive Foaming Polyurethane Grouting Material. Polymers (Basel) 2023; 15:polym15061493. [PMID: 36987273 PMCID: PMC10058686 DOI: 10.3390/polym15061493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/09/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
In this study, the uniaxial compression and cyclic loading and unloading experiments were conducted on the non-water reactive foaming polyurethane (NRFP) grouting material with a density of 0.29 g/cm3, and the microstructure was characterized using scanning electron microscope (SEM) method. Based on the uniaxial compression and SEM characterization results and the elastic-brittle-plastic assumption, a compression softening bond (CSB) model describing the mechanical behavior of micro-foam walls under compression was proposed, and it was assigned to the particle units in a particle flow code (PFC) model simulating the NRFP sample. Results show that the NRFP grouting materials are porous mediums consisting of numerous micro-foams, and with the increasing density, the diameter of the micro-foams increases and the micro-foam walls become thicker. Under compression, the micro-foam walls crack, and the cracks are mainly perpendicular to the loading direction. The compressive stress–strain curve of the NRFP sample contains the linear increasing stage, yielding stage, yield plateau stage, and strain hardening stage, and the compressive strength and elastic modulus are 5.72 MPa and 83.2 MPa, respectively. Under the cyclic loading and unloading, when the number of cycles increases, the residual strain increases, and there is little difference between the modulus during the loading and unloading processes. The stress–strain curves of the PFC model under uniaxial compression and cyclic loading and unloading are consistent with the experimental ones, well indicating the feasibility of using the CSB model and PFC simulation method to study the mechanical properties of NRFP grouting materials. The failure of the contact elements in the simulation model causes the yielding of the sample. The yield deformation propagates almost perpendicular to the loading direction and is distributed in the material layer by layer, which ultimately results in the bulging deformation of the sample. This paper provides a new insight into the application of the discrete element numerical method in NRFP grouting materials.
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Affiliation(s)
- Boyuan Dong
- School of Water Conservancy and Civil Engineering, Zhengzhou University, Zhengzhou 450001, China
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou 450001, China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety, Zhengzhou 450001, China
| | - Mingrui Du
- School of Water Conservancy and Civil Engineering, Zhengzhou University, Zhengzhou 450001, China
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou 450001, China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety, Zhengzhou 450001, China
- Correspondence:
| | - Hongyuan Fang
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou 450001, China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety, Zhengzhou 450001, China
- Yellow River Laboratory, Zhengzhou University, Zhengzhou 450001, China
| | - Fuming Wang
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology, Zhengzhou 450001, China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety, Zhengzhou 450001, China
- Yellow River Laboratory, Zhengzhou University, Zhengzhou 450001, China
| | - Haoyue Zhang
- School of Water Conservancy and Civil Engineering, Zhengzhou University, Zhengzhou 450001, China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety, Zhengzhou 450001, China
- Yellow River Laboratory, Zhengzhou University, Zhengzhou 450001, China
| | - Longhui Zhu
- Shenzhen Feiyang Protech Corp., Ltd., Shenzhen 518000, China
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Miao Y, Yin J, Du W, Chen L. Mechanical behavior of nanorubber reinforced epoxy over a wide strain rate loading. NANO MATERIALS SCIENCE 2023. [DOI: 10.1016/j.nanoms.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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Effects of preparation routes on the physical and rheological properties of isosorbide-based thermoplastic polyurethanes. Macromol Res 2023; 31:133-142. [PMID: 36844252 PMCID: PMC9942074 DOI: 10.1007/s13233-023-00125-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 09/22/2022] [Accepted: 10/11/2022] [Indexed: 02/23/2023]
Abstract
Biomass-derived isosorbide (ISB) is a promising alternative to petroleum-based monomers in industrial plastics. In this study, ISB-based thermoplastic polyurethanes (ISB-TPUs) were prepared using ISB as a biomass chain extender, and the effects of the preparation route on the structural and physical properties of the resultant polymers were investigated. Prepolymer methods were more suitable for obtaining the desired molecular weights (MWs) and physical properties of ISB-TPUs than the one-shot method. The presence of the solvent and catalyst in the prepolymer step had significant effects on the structural and physical properties of the resultant polymer. Among several prepolymer conditions, the solvent- and catalyst-free methods were the most suitable for preparing commercial-level ISB-TPUs, with number- and weight-average MWs (M n and M w ) of 32,881 and 90,929 g mol-1, respectively, and a tensile modulus (E) and ultimate tensile strength (UTS) of 12.0 and 40.2 MPa, respectively. In comparison, the presence of a catalyst in the prepolymer step resulted in lower MWs and mechanical properties (81,033 g mol-1 and 18.3 MPa of M w and UTS, respectively). The co-existence of the catalyst/solvent led to a further decline in the properties of ISB-TPUs (26,506 and 10.0 MPa of M w and UTS, respectively). ISB-TPU prepared via the solvent- and catalyst-free methods exhibited remarkable elastic recovery when subjected to up to 1000% strain in mechanical cycling tests. Rheological characterization confirmed the thermo-reversible phase change (thermoplasticity) of the polymer. Graphical abstract Supplementary Information The online version contains supplementary material available at 10.1007/s13233-023-00125-w.
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Low Impact Velocity Modeling of 3D Printed Spatially Graded Elastomeric Lattices. Polymers (Basel) 2022; 14:polym14214780. [DOI: 10.3390/polym14214780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/25/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
Additive manufacturing technologies have facilitated the construction of intricate geometries, which otherwise would be an extenuating task to accomplish by using traditional processes. Particularly, this work addresses the manufacturing, testing, and modeling of thermoplastic polyurethane (TPU) lattices. Here, a discussion of different unit cells found in the literature is presented, along with the based materials used by other authors and the tests performed in diverse studies, from which a necessity to improve the dynamic modeling of polymeric lattices was identified. This research focused on the experimental and numerical analysis of elastomeric lattices under quasi-static and dynamic compressive loads, using a Kelvin unit cell to design and build non-graded and spatially side-graded lattices. The base material behavior was fitted to an Ogden 3rd-order hyperelastic material model and used as input for the numerical work through finite element analysis (FEA). The quasi-static and impact loading FEA results from the lattices showed a good agreement with the experimental data, and by using the validated simulation methodology, additional special cases were simulated and compared. Finally, the information extracted from FEA allowed for a comparison of the performance of the lattice configurations considered herein.
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Fang H, Zheng Q, Du M, Liu J, Zhang C, Wang Z, Wang F. Study of the mechanical properties and constitutive model of the roadbed rehabilitation polyurethane grouting materials under uniaxial compression. J Appl Polym Sci 2022. [DOI: 10.1002/app.52276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hongyuan Fang
- School of Water Conservancy Engineering Zhengzhou University Zhengzhou China
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology Zhengzhou China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety Zhengzhou China
| | - Qiankun Zheng
- School of Water Conservancy Engineering Zhengzhou University Zhengzhou China
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology Zhengzhou China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety Zhengzhou China
| | - Mingrui Du
- School of Water Conservancy Engineering Zhengzhou University Zhengzhou China
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology Zhengzhou China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety Zhengzhou China
| | | | - Chao Zhang
- School of Water Conservancy Engineering Zhengzhou University Zhengzhou China
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology Zhengzhou China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety Zhengzhou China
| | - Zhenyang Wang
- School of Water Conservancy Engineering Zhengzhou University Zhengzhou China
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology Zhengzhou China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety Zhengzhou China
| | - Fuming Wang
- School of Water Conservancy Engineering Zhengzhou University Zhengzhou China
- National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology Zhengzhou China
- Collaborative Innovation Center of Water Conservancy and Transportation Infrastructure Safety Zhengzhou China
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The Dynamic Impact Response of 3D-Printed Polymeric Sandwich Structures with Lattice Cores: Numerical and Experimental Investigation. Polymers (Basel) 2021; 13:polym13224032. [PMID: 34833331 PMCID: PMC8622326 DOI: 10.3390/polym13224032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/20/2021] [Accepted: 11/20/2021] [Indexed: 11/17/2022] Open
Abstract
This paper proposes a dynamic drop weight impact simulation to predict the impact response of 3D printed polymeric sandwich structures using an explicit finite element (FE) approach. The lattice cores of sandwich structures were based on two unit cells, a body-centred cubic (BCC) and an edge-centred cubic (ECC). The deformation and the peak acceleration, referred to as the g-max score, were calculated to quantify their shock absorption characteristic. For the FE results verification, a falling mass impact test was conducted. The FE results were in good agreement with experimental measurements. The results suggested that the strut diameter, strut length, number and orientation, and the apparent material stiffness of the lattice cores had a significant effect on their deformation behavior and shock absorption capability. In addition, the BCC lattice core with a thinner strut diameter and low structural height might lead to poor shock absorption capability caused by structure collapse and border effect, which could be improved by increasing its apparent material stiffness. This dynamic drop impact simulation process could be applied across numerous industries such as footwear, sporting goods, personal protective equipment, packaging, or biomechanical implants.
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Vidakis N, Petousis M, Korlos A, Velidakis E, Mountakis N, Charou C, Myftari A. Strain Rate Sensitivity of Polycarbonate and Thermoplastic Polyurethane for Various 3D Printing Temperatures and Layer Heights. Polymers (Basel) 2021; 13:polym13162752. [PMID: 34451291 PMCID: PMC8401430 DOI: 10.3390/polym13162752] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 12/12/2022] Open
Abstract
In this work, strain rate sensitivity was studied for 3D-printed polycarbonate (PC) and thermoplastic polyurethane (TPU) materials. Specimens were fabricated through fused filament fabrication (FFF) additive manufacturing (AM) technology and were tested at various strain rates. The effects of two FFF process parameters, i.e., nozzle temperature and layer thickness, were also investigated. A wide analysis for the tensile strength (MPa), the tensile modulus of elasticity (MPa), the toughness (MJ/m3) and the strain rate sensitivity index ‘m’ was conducted. Additionally, a morphological analysis was conducted using scanning electron microscopy (SEM) on the side and the fracture area of the specimens. Results from the different strain rates for each material were analyzed, in conjunction with the two FFF parameters tested, to determine their effect on the mechanical response of the two materials. PC and TPU materials exhibited similarities regarding their temperature response at different strain rates, while differences in layer height emerged regarding the appropriate choice for the FFF process. Overall, strain rate had a significant effect on the mechanical response of both materials.
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Affiliation(s)
- Nectarios Vidakis
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Greece; (N.V.); (E.V.); (N.M.); (C.C.); (A.M.)
| | - Markos Petousis
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Greece; (N.V.); (E.V.); (N.M.); (C.C.); (A.M.)
- Correspondence: ; Tel.: +30-2810379227
| | - Apostolos Korlos
- Department of Industrial Engineering and Management, International Hellenic University, 14th km Thessaloniki—N. Moudania, Thermi, 57001 Thessaloniki, Greece;
| | - Emmanouil Velidakis
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Greece; (N.V.); (E.V.); (N.M.); (C.C.); (A.M.)
| | - Nikolaos Mountakis
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Greece; (N.V.); (E.V.); (N.M.); (C.C.); (A.M.)
| | - Chrisa Charou
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Greece; (N.V.); (E.V.); (N.M.); (C.C.); (A.M.)
| | - Adrian Myftari
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Greece; (N.V.); (E.V.); (N.M.); (C.C.); (A.M.)
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Xu B, Yin B, Li Q, Kuang X, Jia H. Tribological performance of self‐lubricating polyurethane elastomer compounding with the modified ultra‐high molecular weight polyethylene. POLYM ENG SCI 2021. [DOI: 10.1002/pen.25719] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Bo Xu
- Department of Power Machinery School of Automotive and Traffic Engineering, Jiangsu University Zhenjiang China
| | - Bifeng Yin
- Department of Power Machinery School of Automotive and Traffic Engineering, Jiangsu University Zhenjiang China
| | - Qianzhu Li
- Department of Material Development Institute of Advanced Polymer Materials Technology, Tech‐in Materials Co., Ltd. Nanjing China
| | - Xin Kuang
- Department of Power Machinery School of Automotive and Traffic Engineering, Jiangsu University Zhenjiang China
| | - Hekun Jia
- Department of Power Machinery School of Automotive and Traffic Engineering, Jiangsu University Zhenjiang China
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