scholarly journals Design and Thermal Stability Analysis of Swing Micro-Mirror Structure for Gravitational Wave Observatory in Space

Machines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 104
Author(s):  
Kunyao Zheng ◽  
Mingming Xu
Keyword(s):  
Thermal Stability ◽  
Gravitational Wave ◽  
Natural Frequency ◽  
Solution Method ◽  
Element Analysis ◽  
Temperature Changes ◽  
First Order ◽  
Angle Deviation ◽  
Thermal Stability Of ◽  
Mirror Structure

A kind of swing micro-mirror structure with high stability for gravitational wave observatory in space is proposed in this paper. As the key interface instrument in the gravitational wave observatory, the swing micro-mirror structure plays a very important role. Firstly, the 3D model of the mechanism is designed and established. Then, the solution method of the index of stability, pointing jitter, is researched. After that, the thermal stability and the first-order natural frequency of the mechanism are researched via finite element analysis. The first-order natural frequency of the mechanism is 247.55 Hz, which can meet the requirements of the design. It can be seen from the results of the simulation, the amplitude spectral density of the mirror angle deviation is 3.975 nrad/√Hz when the range of temperature variation is 0.1 °C, which is able to meet the requirements of the design. The thermal stability has a closed relationship with the structural stability around the X-axis. In addition, this article also studies the thermal stability of the mechanism in the case of temperature changes in different directions. It is found that the thermal stability of the mechanism around the Y-axis would be significantly affected by the temperature changes along the Y-axis.

Bionanomaterials: Thermal Stability of the Oleic Acid / alpha- and beta-cyclodextrin Complexes

2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Daniel I. Hadaruga ◽  
Nicoleta G. Hadaruga ◽  
Anca Hermenean ◽  
Adrian Rivis ◽  
Vasile Paslaru ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Oleic Acid ◽  
Solution Method ◽  
Degradation Products ◽  
Water Solution ◽  
Fatty Acid Esters ◽  
Cyclodextrin Complexes ◽  
Free Oleic Acid ◽  
Thermal Stability Of ◽  
Acid Esters

This paper presents the thermal stability of the oleic acid encapsulated in a- and b - cyclodextrin. The complexation of the oleic acid was achieved by the ethanol-water solution method and the nanoparticles were analyzed by DSC. The free oleic acid and the encapsulated one were subjected to the thermal degradation in the range of 50-150�C and the degradation products were identified and quantified by GC-MS analysis of the fatty acid esters obtained by deriving with methanol/boron trifluoride, both for free compounds and for the encapsulated ones. The oleic acid complexes were very stable in this range of temperature.

Syntheses, Crystal Structures and Thermal Stability of Co(II) and Zn(II) Complexes with Ethyl Carbazate

2005 ◽  
Vol 60 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Tong-Lai Zhang ◽  
Jiang-Chuang Song ◽  
Jian-Guo Zhang ◽  
Gui-Xia Ma ◽  
Kai-Bei Yu
Keyword(s):  
Thermal Stability ◽  
Aqueous Solutions ◽  
Diffraction Analysis ◽  
Single Crystals ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
Thermal Stabilities ◽  
X Ray ◽  
Thermal Stability Of

Cobalt(II) and zinc(II) complexes of ethyl carbazate (ECZ), [Co(ECZ)3](NO3)2 and [Zn(ECZ)3] (NO3)2, were synthesized. Single crystals of these two compounds were grown from aqueous solutions using a slow evaporation method. Their structures have been determined by X-ray diffraction analysis. Both of them are monoclinic with space group P21/n. The complexes are further characterized by element analysis and IR measurements. Their thermal stabilities are studied by using TG-DTG, DSC techniques. When heated to 350 °C, only metal oxide was left for both complexes.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

scholarly journals Response of a Two-Degree-of-Freedom Vibration System with Rough Contact Interfaces

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Zhiqiang Huang ◽  
Xun Peng ◽  
Gang Li ◽  
Lei Hao
Keyword(s):  
Natural Frequency ◽  
Degree Of Freedom ◽  
Element Analysis ◽  
Chaotic Motions ◽  
First Order ◽  
Vibration Properties ◽  
Ground System ◽  
Jump Frequencies ◽  
Two Degree Of Freedom ◽  
Seismic Vibrator

This paper is focused on the influence of the rough contact interfaces on the dynamics of a coupled mechanical system. For this purpose, a two-degree-of-freedom model of a coupled seismic-vibrator-rough-ground system is proposed with which the nonlinear vibration properties are analyzed. In this model, the force-deflection characteristic of the contact interfaces is determined by finite element analysis. By analyzing the undamped free vibration, it was found that the variation of the second-order natural frequency with amplitude increases with rougher contact interfaces; however, the amplitude has little influence on the first-order natural frequency of the system. For the harmonic excited analysis, the jump frequencies and hysteretic region both decrease with rougher contact interfaces. Moreover, it is inferred from the bifurcation diagrams that, increasing the excitation force, the system can bring about chaotic motions on rough contact interfaces.

Finite Element Analysis and Optimization of Thermal Deformation of Resin Concrete Manufacturing Bases

2014 ◽  
Vol 543-547 ◽  
pp. 4010-4013
Author(s):  
Yao Chen ◽  
Xiu Xia Liang ◽  
Shuang Qiu
Keyword(s):  
Thermal Stability ◽  
Machine Tool ◽  
Thermal Deformation ◽  
Precision Machining ◽  
Element Analysis ◽  
Excellent Thermal Stability ◽  
Good Thermal Stability ◽  
Machining Center ◽  
Ultra Precision ◽  
Thermal Stability Of

Resin concrete generally has good mechanical properties, excellent thermal stability and great vibration resistance, the model of the ultra-precision machining center bed is established to study the thermal stability of the resin concrete using virtual reality and collaborative simulation technology based on Pro/E and ANSYS Workbench. The main factors that affect the machine tool bed thermal deformation were found through analyzing the deformation results and the materials and restrain conditions were optimized. The results proved that the optimized machine tool bed has good thermal stability and theoretical basis was provided to improve the thermal stability of the ultra-precision machining centers.

scholarly journals Stability Analysis of Multispan Pipeline Embedded in Temperature-Dependent Matrix

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Nan Wu ◽  
Yongshou Liu ◽  
Guojun Tong ◽  
Jiayin Dai
Keyword(s):  
Natural Frequency ◽  
Critical Velocity ◽  
Critical Pressure ◽  
Dynamic Stiffness ◽  
Second Order ◽  
Temperature Dependent ◽  
Temperature Changes ◽  
First Order ◽  
The Stability ◽  
Increasing Temperature

In this paper, dynamic stiffness method is used to study the stability of multispan pipelines in temperature-dependent matrix. The effects of temperature changes and different span combinations on the natural frequency, critical velocity, and critical pressure of pipelines are discussed. The main conclusions are obtained and shown as follows. The increase of temperature will lead to the decrease of the first three order natural frequencies. The first two order critical velocities and critical pressure of the system will also decrease with increasing temperature. The change of span combination has no influence on the first-order critical velocity and first-order critical pressure of the system, but it has influence on the second order. The influence of the change of span combination on the first-order natural frequency is regular, but that on the second-order and third-order is not. The increase of the velocity will change the instability form of systems with different span combinations, while the change of the pressure inside the tube will not change the instability form of the system.

scholarly journals Analytical model for flexural damping responses of CFRP cantilever beams in the low-frequency vibration

2018 ◽  
Vol 37 (4) ◽  
pp. 669-681 ◽  
Author(s):  
Mo Yang ◽  
Yefa Hu ◽  
Jinguang Zhang ◽  
Guoping Ding ◽  
Chunsheng Song
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequency ◽  
Analytical Model ◽  
Flexural Vibration ◽  
Maximum Error ◽  
Damping Capacity ◽  
Element Analysis ◽  
First Order ◽  
Specific Damping Capacity

In this paper, an analytical model for the flexural vibration damping of Carbon Fiber Reinforced Plastics (CFRP) cantilever beams was proposed, which is based on the Lamination Theory and Euler–Bernoulli Beam Theory. By using a finite element analysis and an analytical model, four sets of specific damping capacity with different pavement schemes were predicted, and flexural vibration test and damping analysis were carried out. Comparing the analytical model, finite element analysis, and test results, it could be found that the analytical model had relatively good accuracy in predicting the first-order natural frequency and specific damping capacity of the bending vibration of CFRP beams. The maximum error of the first-order natural frequency between the analysis result and the experimental result was 7.05%; the maximum specific damping capacity error was only 5.65%. Comparing the finite element analysis method and the experiment results, the maximum error of the first-order natural frequency was 7.8%, the error of the specific damping capacity was bigger, and the [±30°]5S specimen was as high as 18.7%. However, there was a significant error when the analytical model was used to predict the second-order natural frequency and the specific damping capacity of CFRP beam’s flexural vibration.

A study of partial layout of adhesive on the thermal drift of MEMS capacitive accelerometers

2017 ◽  
Vol 31 (07) ◽  
pp. 1741006 ◽  
Author(s):  
Peng Peng ◽  
Wu Zhou ◽  
Huijun Yu ◽  
Qu Hao ◽  
Bei Peng ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Drift ◽  
Mems Devices ◽  
Element Analysis ◽  
Adhesive Bonds ◽  
Microelectromechanical System ◽  
Die Attachment ◽  
Capacitive Accelerometer ◽  
Stress And Deformation ◽  
Thermal Stability Of

The die attachment adhesive is commonly fully deposited on the substrate to connect the chips and the package shell in the packaging of microelectromechanical system (MEMS) devices. The packaging stress and deformation will be changed under temperature variation and further impact the thermal stability of devices. This paper describes a partial layout of die attachment adhesive used in a comb MEMS capacitive accelerometer, which can attenuate the thermal deformation and reduce the thermal drift of the sensor. The accelerometers with the bonded area designed from the global portion to nonsensitive portion of the sensor die are modeled by using finite element analysis (FEA) to study the deformation of the sensitive component induced by temperature change, and the corresponding thermal drift is obtained by simulation and theoretical methods. Both the results indicate that the thermal drift will decrease when the length of the unbonded area is larger than about 700 μm, and when the adhesive bonds only in the area of the nonsensitive portion of the sensor, the thermal drift will reduce about 19% relative to the global attachment. The partial layout of die attachment adhesive is therefore a useful method to improve the thermal stability for stress-sensitive MEMS devices.

scholarly journals Investigation of the Damping Capacity of CFRP Raft Frames

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 653
Author(s):  
Jinguang Zhang ◽  
Jun Rao ◽  
Lei Ma ◽  
Xianglong Wen
Keyword(s):  
Natural Frequency ◽  
Simulation Analysis ◽  
Plate Theory ◽  
Damping Ratio ◽  
Great Influence ◽  
Maximum Error ◽  
Bottom Plate ◽  
Damping Capacity ◽  
Element Analysis ◽  
First Order

In this paper, based on the composite laminated plate theory and a strain energy model, the damping capacity of a Carbon Fiber Reinforced Plastics (CFRP) raft frame was studied. According to the finite element analysis (FEA) and damping ratio prediction model, the influences of different layups on the damping capacity of the raft frame and its components (top/bottom plate and I-support) were discussed. Comparing the FEA results with the test results, it can be figured out that the CFRP laminate layup has a great influence on the damping ratio of the raft frame, and the maximum error of the first-order natural frequency and damping ratio of the top/bottom plate were 5.6% and 15.1%, respectively. The maximum error of the first-order natural frequency of the I-support between the FEA result and the test result was 7.5%, suggesting that because of the stress concentration, the error of the damping ratio was relatively large. As for the raft frame, the damping performance was affected by the I-support arrangement and the simulation analysis was in good agreement with the experimental results. This study can provide a useful reference for improving the damping performance of CFRP raft frames.

Structure Design of a Machining Center Bed Based on Topology Optimization Technique

2014 ◽  
Vol 490-491 ◽  
pp. 580-585 ◽  
Author(s):  
Ya Li Ma ◽  
Zhen Gong ◽  
Chao Ma
Keyword(s):  
Topology Optimization ◽  
Natural Frequency ◽  
Conceptual Design ◽  
Optimization Technique ◽  
Structure Design ◽  
Original Structure ◽  
Element Analysis ◽  
First Order ◽  
Machining Center ◽  
Design Structure

This paper applies efficiently topology optimization technique to the conceptual design of a bed structure of machining center, which achieves for sufficient rigidity and reasonable distribution of weight of the bed. Firstly, conceptual design of the bed structure is obtained by using SIMP method under the conditions of a multi-objective optimization considering both the weighted structure compliance and the first-order natural frequency on multiple load cases and volume constraints. Subsequently, size design is employed to determine the main dimensions of the supporting plates and reinforcing ribs. During this stage an exhaustion method is identified to select suitable dimensions to optimize the structure performance. Finally, The Finite Element Analysis (FEM) is utilized for comparison of optimal and original bed structure. The FEM results indicate that the optimal design structure can reduce the mass by 6.6% with the less stiffness fluctuation and the first-order natural frequency can also improve by 7.9% compared with the original structure.

Sign in / Sign up

Export Citation Format

Share Document