Wave absorbing structures have been widely applied in many countries. In the present paper, the wave heights in front of a vertical wave absorbing structure with rubble foundation as well as in the wave chamber of the...Wave absorbing structures have been widely applied in many countries. In the present paper, the wave heights in front of a vertical wave absorbing structure with rubble foundation as well as in the wave chamber of the structure are analysed using an approximative calculation method, and the dissipating effect of the structure is verified. On the basis of the results of regular waves, the relative wave heights of irregular waves in front of the wave absorbing structure as well as in the chamber have also been analysed.展开更多
A new wave energy dissipation structure is proposed, aiming to optimize the dimensions of the structure and make the reflection of the structure maintain a low level within the scope of the known frequency band. An op...A new wave energy dissipation structure is proposed, aiming to optimize the dimensions of the structure and make the reflection of the structure maintain a low level within the scope of the known frequency band. An optimal extended ANFIS model combined with the wave reflection coefficient analysis for the estimation of the structure dimensions is established. In the premise of lower wave reflection coefficient, the specific sizes of the structure are obtained inversely, and the contribution of each related parameter on the structural reflection performance is analyzed. The main influencing factors are determined. It is found that the optimal dimensions of the proposed structure exist, which make the wave absorbing performance of the structure reach a perfect status under a wide wave frequency band.展开更多
This paper introduces a low-cost infrared absorbing structure for an uncooled infrared detector in a standard 0.5 m CMOS technology and post-CMOS process. The infrared absorbing structure can be created by etching the...This paper introduces a low-cost infrared absorbing structure for an uncooled infrared detector in a standard 0.5 m CMOS technology and post-CMOS process. The infrared absorbing structure can be created by etching the surface sacrificial layer after the CMOS fabrication, without any additional lithography and deposition procedures. An uncooled infrared microbolometer is fabricated with the proposed infrared absorbing structure.The microbolometer has a size of 6565 m2and a fill factor of 37.8%. The thermal conductance of the microbolometer is calculated as 1.3310 5W/K from the measured response to different heating currents. The fabricated microbolometer is irradiated by an infrared laser, which is modulated by a mechanical chopper in a frequency range of 10–800 Hz. Measurements show that the thermal time constant is 0.995 ms and the thermal mass is 1.3210 8J/K. The responsivity of the microbolometer is about 3.03104V/W at 10 Hz and the calculated detectivity is 1.4108cm Hz1=2/W.展开更多
Three-dimensional(3D)printing allows for the creation of complex,layered structures with precise micro and macro architectures that are not achievable through traditional methods.By designing 3D structures with geomet...Three-dimensional(3D)printing allows for the creation of complex,layered structures with precise micro and macro architectures that are not achievable through traditional methods.By designing 3D structures with geometric precision,it is possible to achieve selective regulation of mechanical properties,enabling efficient dissipation of mechanical energy.In this study,a series of modular samples inspired by the Bouligand structure were designed and produced using a direct ink writing system,along with a classical printable polydimethylsiloxane ink.By altering the angles of filaments in adjacent layers(from 30◦to 90◦)and the filament spacing during printing(from 0.8 mm to 2.4 mm),the mechanical properties of these modular samples can be adjusted.Compression mechanical testing revealed that the 3D printed modular Bouligand structures exhibit stress-strain responses that enable multiple adjustments of the elastic modulus from 0.06 MPa to over 0.8 MPa.The mechanical properties were adjusted more than 10 times in printed samples prepared using uniform materials.The gradient control mechanism of mechanical properties during this process was analyzed using finite element analysis.Finally,3D printed customized modular Bouligand structures can be assembled to create an array with Bouligand structures displaying various orientations and interlayer details tailored to specific requirements.By decomposing the original Bouligand structure and then assembling the modular samples into a specialized array,this research aims to provide parameters for achieving gradient energy absorption structures through modular 3D printing.展开更多
1 Introduction Early attempts to create a sound absorber which would function without the involvement of any fibrous or porous damping material go far back to K. A. Veliszhanina, S. N. Rschevkin and others as was out...1 Introduction Early attempts to create a sound absorber which would function without the involvement of any fibrous or porous damping material go far back to K. A. Veliszhanina, S. N. Rschevkin and others as was outlined in Ref. [1]. 30 years ago, D. Y. MAA[2] was first in proposing a practicable design concept and calculation model for Micro-Perforated Absorber (MPA) prototypes which still forms the basis for various applications. During the past 12 years the Fraunhofer IBP developed a whole family of MPA products in close cooperation with 8 or more industrial partners operating in a variety of widely differing market segments. Meanwhile a large number of MPA modules and surface elements have evolved from MAA's creative pioneer work. More and more ambitious acousticians have, more recently, caught on this attractive idea of employing absorbers made of non-fibrous, non-abrasive materials with non-polluting, almost closed and optically attractive surfaces. MPA structures have played an important part in a long-standing and on-going effort at IBP to establish novel Alternative Fibreless Absorber (ALFA) tools for a better noise control and acoustic comfort.展开更多
文摘Wave absorbing structures have been widely applied in many countries. In the present paper, the wave heights in front of a vertical wave absorbing structure with rubble foundation as well as in the wave chamber of the structure are analysed using an approximative calculation method, and the dissipating effect of the structure is verified. On the basis of the results of regular waves, the relative wave heights of irregular waves in front of the wave absorbing structure as well as in the chamber have also been analysed.
基金financially supported by the National Natural Science Foundation of China(Grant No.51279028)the Public Science and Technology Research Funds Projects of Ocean(Grant No.201405025-1)
文摘A new wave energy dissipation structure is proposed, aiming to optimize the dimensions of the structure and make the reflection of the structure maintain a low level within the scope of the known frequency band. An optimal extended ANFIS model combined with the wave reflection coefficient analysis for the estimation of the structure dimensions is established. In the premise of lower wave reflection coefficient, the specific sizes of the structure are obtained inversely, and the contribution of each related parameter on the structural reflection performance is analyzed. The main influencing factors are determined. It is found that the optimal dimensions of the proposed structure exist, which make the wave absorbing performance of the structure reach a perfect status under a wide wave frequency band.
基金Project supported by the National Natural Science Foundation of China(Nos.60806038,61131004,61274076)the National HighTechnology Research and Development Program of China(Nos.2006AA040102,2006AA040106)
文摘This paper introduces a low-cost infrared absorbing structure for an uncooled infrared detector in a standard 0.5 m CMOS technology and post-CMOS process. The infrared absorbing structure can be created by etching the surface sacrificial layer after the CMOS fabrication, without any additional lithography and deposition procedures. An uncooled infrared microbolometer is fabricated with the proposed infrared absorbing structure.The microbolometer has a size of 6565 m2and a fill factor of 37.8%. The thermal conductance of the microbolometer is calculated as 1.3310 5W/K from the measured response to different heating currents. The fabricated microbolometer is irradiated by an infrared laser, which is modulated by a mechanical chopper in a frequency range of 10–800 Hz. Measurements show that the thermal time constant is 0.995 ms and the thermal mass is 1.3210 8J/K. The responsivity of the microbolometer is about 3.03104V/W at 10 Hz and the calculated detectivity is 1.4108cm Hz1=2/W.
基金National Key Research and Development Program of China(2022YFB4600102)the strategic priority research program of the Chinese Academy of Sciences(XDB0470000)+1 种基金Western Young Scholars Foundations of the Chinese Academy of Sciences,the National Natural Science Foundation of China(52175201,52108410)Project ZR2023ME061 supported by Shandong Provincial Natural Science Foundation.
文摘Three-dimensional(3D)printing allows for the creation of complex,layered structures with precise micro and macro architectures that are not achievable through traditional methods.By designing 3D structures with geometric precision,it is possible to achieve selective regulation of mechanical properties,enabling efficient dissipation of mechanical energy.In this study,a series of modular samples inspired by the Bouligand structure were designed and produced using a direct ink writing system,along with a classical printable polydimethylsiloxane ink.By altering the angles of filaments in adjacent layers(from 30◦to 90◦)and the filament spacing during printing(from 0.8 mm to 2.4 mm),the mechanical properties of these modular samples can be adjusted.Compression mechanical testing revealed that the 3D printed modular Bouligand structures exhibit stress-strain responses that enable multiple adjustments of the elastic modulus from 0.06 MPa to over 0.8 MPa.The mechanical properties were adjusted more than 10 times in printed samples prepared using uniform materials.The gradient control mechanism of mechanical properties during this process was analyzed using finite element analysis.Finally,3D printed customized modular Bouligand structures can be assembled to create an array with Bouligand structures displaying various orientations and interlayer details tailored to specific requirements.By decomposing the original Bouligand structure and then assembling the modular samples into a specialized array,this research aims to provide parameters for achieving gradient energy absorption structures through modular 3D printing.
文摘1 Introduction Early attempts to create a sound absorber which would function without the involvement of any fibrous or porous damping material go far back to K. A. Veliszhanina, S. N. Rschevkin and others as was outlined in Ref. [1]. 30 years ago, D. Y. MAA[2] was first in proposing a practicable design concept and calculation model for Micro-Perforated Absorber (MPA) prototypes which still forms the basis for various applications. During the past 12 years the Fraunhofer IBP developed a whole family of MPA products in close cooperation with 8 or more industrial partners operating in a variety of widely differing market segments. Meanwhile a large number of MPA modules and surface elements have evolved from MAA's creative pioneer work. More and more ambitious acousticians have, more recently, caught on this attractive idea of employing absorbers made of non-fibrous, non-abrasive materials with non-polluting, almost closed and optically attractive surfaces. MPA structures have played an important part in a long-standing and on-going effort at IBP to establish novel Alternative Fibreless Absorber (ALFA) tools for a better noise control and acoustic comfort.