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学者姓名:代岩伟
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Abstract :
PurposeThis study aims to characterize the mechanical properties of sintered nano-silver under various sintering processes by nano-indentation tests.Design/methodology/approachThrough microstructure observations and characterization, the influences of sintering process on the microstructure evolutions of sintered nano-silver were presented. And, the indentation load, indentation displacement curves of sintered silver under various sintering processes were measured by using nano-indentation test. Based on the nano-indentation test, a reverse analysis of the finite element calculation was used to determine the yielding stress and hardening exponent.FindingsThe porosity decreases with the increase of the sintering temperature, while the average particle size of sintered nano-silver increases with the increase of sintering temperature and sintering time. In addition, the porosity reduced from 34.88%, 30.52%, to 25.04% if the ramp rate was decreased from 25 degrees C/min, 15 degrees C/min, to 5 degrees C/min, respectively. The particle size appears more frequently within 1 mu m and 2 mu m under the lower ramp rate. With reverse analysis, the strain hardening exponent gradually heightened with the increase of temperature, while the yielding stress value decreased significantly with the increase of temperature. When the sintering time increased, the strain hardening exponent increased slightly.Practical implicationsThe mechanical properties of sintered nano-silver under different sintering processes are clearly understood.Originality/valueThis paper could provide a novel perspective on understanding the sintering process effects on the mechanical properties of sintered nano-silver.
Keyword :
Microstructure evolution Microstructure evolution Nano-indentation Nano-indentation Elastoplastic behaviors Elastoplastic behaviors Sintered nano-silver Sintered nano-silver Sintering process Sintering process
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GB/T 7714 | Dai, Yanwei , Zhao, Libo , Qin, Fei et al. Elastoplastic nanoindentation behaviors of sintered nano-silver under various sintering parameters [J]. | SOLDERING & SURFACE MOUNT TECHNOLOGY , 2024 . |
MLA | Dai, Yanwei et al. "Elastoplastic nanoindentation behaviors of sintered nano-silver under various sintering parameters" . | SOLDERING & SURFACE MOUNT TECHNOLOGY (2024) . |
APA | Dai, Yanwei , Zhao, Libo , Qin, Fei , Chen, Si . Elastoplastic nanoindentation behaviors of sintered nano-silver under various sintering parameters . | SOLDERING & SURFACE MOUNT TECHNOLOGY , 2024 . |
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Abstract :
To simulate structural crack propagation and predict fatigue life, the extended finite element method (XFEM) combined with the virtual crack closure technique (VCCT) is adopted in this paper. Firstly, the underlying principles of the XFEM-VCCT framework are elaborated comprehensively, mainly including the calculation of crack tip energy release rate based on VCCT, the simulation of element cracking utilizing the phantom nodes, and the computation of structural responses under cyclic loading through the direct cyclic analysis. In addition, to calculate the crack propagation length, an interpolation method to obtain the crack tip coordinates is developed based on tracking and locating the crack by the level set functions. Meanwhile, to compensate the defect that the fatigue life is often overestimated when dealing with the complex mode crack in complex structure through XFEM-VCCT, a simple improved algorithm based on the average rate concept is proposed without altering the XFEM-VCCT framework. Based on specific examples, the necessity and accuracy of the improved algorithm are fully verified by comparing with the original method, and the fatigue life predicted by the improved algorithm is more consistent with reality. Finally, this method is successfully applied to the simulation and analyses for a typical ship stiffened plate structure, demonstrating good engineering applicability.
Keyword :
Fatigue crack propagation simulation Fatigue crack propagation simulation Virtual crack closure technology Virtual crack closure technology Extended finite element method Extended finite element method Energy release rate Energy release rate Improved fatigue life algorithm Improved fatigue life algorithm
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GB/T 7714 | Chen, Zhiying , Dai, Yanwei , Liu, Yinghua . Structural fatigue crack propagation simulation and life prediction based on improved XFEM-VCCT [J]. | ENGINEERING FRACTURE MECHANICS , 2024 , 310 . |
MLA | Chen, Zhiying et al. "Structural fatigue crack propagation simulation and life prediction based on improved XFEM-VCCT" . | ENGINEERING FRACTURE MECHANICS 310 (2024) . |
APA | Chen, Zhiying , Dai, Yanwei , Liu, Yinghua . Structural fatigue crack propagation simulation and life prediction based on improved XFEM-VCCT . | ENGINEERING FRACTURE MECHANICS , 2024 , 310 . |
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Abstract :
阐述ChatGPT在材料力学教学中的可能应用场景,从积极影响和消极风险两个方面论述在材料力学教学过程中使用ChatGPT的优势和制约因素,并对普通材料力学授课教师在未来教学过程中如何应对以ChatGPT为代表的人工智能技术提出观点和看法.
Keyword :
ChatGPT ChatGPT 人工智能 人工智能 材料力学 材料力学
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GB/T 7714 | 代岩伟 , 秦飞 . ChatGPT在材料力学教学中的应用前景和风险因素探讨 [J]. | 中国教育技术装备 , 2024 , (12) : 37-39 . |
MLA | 代岩伟 et al. "ChatGPT在材料力学教学中的应用前景和风险因素探讨" . | 中国教育技术装备 12 (2024) : 37-39 . |
APA | 代岩伟 , 秦飞 . ChatGPT在材料力学教学中的应用前景和风险因素探讨 . | 中国教育技术装备 , 2024 , (12) , 37-39 . |
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Abstract :
As one of the most important topics studied in creep fracture mechanics, mechanics fields at 3D sharp V-notch front tip in creeping solids have drawn remarkable attention at present. In this paper, the higher-order asymptotic analysis is carried out for 3D sharp V-notch front tip fields in creeping solids subjected to mode I loading, and a 3D higher-order term solution is theoretically proposed by introducing the out-of-plane stress factor Tz to establish the 3D nonlinear governing equations of front tip fields. The present higher-order asymptotic solution for 3D sharp V-notch can naturally be degenerated to that for 3D crack. It is found that the stress exponents and angular distribution functions of higher-order terms for 3D notch and crack are highly related to Tz. The proposed 3D higher-order term solution overall shows better agreement with the FEA results than the existing 3D leading-term solution and 2D higher-order term solutions available in the literature, especially for smaller notch angle and shorter ligament lengths. Based on the 3D higherorder asymptotic solution, a new fracture parameter AT2 is given and combined with Tz to characterize 3D constraint effect. It is noted that the effects of AT2 and Tz on 3D constraint are highly interlinked rather than simply separated into in-plane and out-of-plane parts. The present 3D higher-order asymptotic solution can promote the understanding and characterization of 3D constraint effect and is of great significance in the evaluation of 3D fracture behavior and structural failure assessment under creep conditions.
Keyword :
Creeping solid Creeping solid 3D crack 3D crack Higher-order asymptotic solution Higher-order asymptotic solution Constraint effect Constraint effect 3D V-notch 3D V-notch
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GB/T 7714 | Kong, Weichen , Dai, Yanwei , Liu, Yinghua . A higher-order asymptotic solution for 3D sharp V-notch front tip fields in creeping solids [J]. | ENGINEERING FRACTURE MECHANICS , 2024 , 306 . |
MLA | Kong, Weichen et al. "A higher-order asymptotic solution for 3D sharp V-notch front tip fields in creeping solids" . | ENGINEERING FRACTURE MECHANICS 306 (2024) . |
APA | Kong, Weichen , Dai, Yanwei , Liu, Yinghua . A higher-order asymptotic solution for 3D sharp V-notch front tip fields in creeping solids . | ENGINEERING FRACTURE MECHANICS , 2024 , 306 . |
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Abstract :
本文采用有限元方法对表面沉积不同厚度二氧化硅晶圆进行了数值仿真。晶圆表面沉积材料的初始残余应力影响晶圆的翘曲,然而由于测试精度和手段通常难以表征,本文基于数值反演方法获取测样品在沉积过程中的初始残余应力。仿真数据表明,随着二氧化硅厚度的增加,初始残余应力呈现下降的趋势。
Keyword :
晶圆翘曲 晶圆翘曲 薄膜沉积 薄膜沉积 初始残余应力 初始残余应力
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GB/T 7714 | 刘泓利 , 秦飞 , 代岩伟 et al. 二氧化硅/硅晶圆翘曲初始残余应力数值反演研究 [C] //北京力学会第30届学术年会 . 2024 . |
MLA | 刘泓利 et al. "二氧化硅/硅晶圆翘曲初始残余应力数值反演研究" 北京力学会第30届学术年会 . (2024) . |
APA | 刘泓利 , 秦飞 , 代岩伟 , 李晨光 . 二氧化硅/硅晶圆翘曲初始残余应力数值反演研究 北京力学会第30届学术年会 . (2024) . |
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Abstract :
Under the operating conditions of high power and high switching frequency, an insulated gate bipolar transistor (IGBT) chip can produce relatively large power loss, causing the junction temperature to rise rapidly; consequently, the reliability of the IGBT module can be seriously affected. Therefore, it is necessary to accurately predict the junction temperature of the IGBT chip. The resistance capacitance (RC) thermal network model is a commonly used method for IGBT junction temperature prediction. In this paper, the model parameters are obtained by two methods to establish the Cauer thermal network models of the IGBT module. The first method is to experimentally obtain the transient thermal impedance curve of the IGBT module and the structure function and then extract the individual thermal parameters of the Cauer thermal network model; the second method is to obtain the thermal parameters of the thermal network model directly by using theoretical formulas that consider the influence of the heat spreading angle. The predicted junction temperatures of the Cauer thermal network models established by the two methods are compared with the junction temperatures obtained from infrared (IR) measurements during the power cycling test, the junction temperatures measured by the temperature-sensitive electrical parameter (TSEP) method, and the junction temperatures calculated by finite element (FE) analysis. Additionally, the Cauer thermal network models established by the two methods are compared and verified. The results indicate that the Cauer thermal network model established based on theoretical formulas can accurately predict the maximum junction temperature of the IGBT chip, and the calculated temperature for each layer, from the IGBT chip layer to the ceramic layer, also accords well with the FE results. The Cauer thermal network model established based on the experimental test and the structure function can accurately predict the average junction temperature of the IGBT chip.
Keyword :
insulated gate bipolar transistor insulated gate bipolar transistor junction temperature junction temperature Cauer thermal network models Cauer thermal network models
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GB/T 7714 | An, Tong , Zhou, Rui , Qin, Fei et al. Comparative Study of the Parameter Acquisition Methods for the Cauer Thermal Network Model of an IGBT Module [J]. | ELECTRONICS , 2023 , 12 (7) . |
MLA | An, Tong et al. "Comparative Study of the Parameter Acquisition Methods for the Cauer Thermal Network Model of an IGBT Module" . | ELECTRONICS 12 . 7 (2023) . |
APA | An, Tong , Zhou, Rui , Qin, Fei , Dai, Yanwei , Gong, Yanpeng , Chen, Pei . Comparative Study of the Parameter Acquisition Methods for the Cauer Thermal Network Model of an IGBT Module . | ELECTRONICS , 2023 , 12 (7) . |
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Abstract :
Nonproportional loading and residual stresses effects on creep crack tip fields are important topics in fracture mechanics at elevated temperature. In this paper, nonproportional loading and residual stresses effects on creep crack tip fields are systematically investigated based on the novel interpretation of C(t)-integral considering residual stress. With the numerical implementation of the corrected C(t)-integral considering residual stress, the eigenstrain and mechanical induced residual stress effects on the creep crack tip fields are studied. We find that C(t)-integral level is affected remarkably in the presence of residual stress regardless of eigenstrain or mechanical induced residual stresses for creep crack tip under small scale creep. However, level of C*-integral is not significantly influenced under the effects of residual stresses in presence of large-scale creep although the transition creep time is remarkably changed. Otherwise, C(t)-integral is highly affected by loading path under small scale creep. However, C*-integral is independent of the loading path if the creep time is long enough. Nonproportional loading effect on C*-integral is very limited for creep crack tip field according to our study. The investigation given in this paper could deepen the understanding the effects of residual stress and nonproportional loading on the creep crack tip field.
Keyword :
Crack tip fields Crack tip fields C(t)-integral C(t)-integral Residual stress Residual stress Creep crack Creep crack Nonproportional loading Nonproportional loading
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GB/T 7714 | Liu, Wei , Dai, Yanwei , Liu, Yinghua et al. Effects of nonproportional loading and residual stress on creep crack tip fields [J]. | ENGINEERING FRACTURE MECHANICS , 2023 , 281 . |
MLA | Liu, Wei et al. "Effects of nonproportional loading and residual stress on creep crack tip fields" . | ENGINEERING FRACTURE MECHANICS 281 (2023) . |
APA | Liu, Wei , Dai, Yanwei , Liu, Yinghua , Kong, Weichen . Effects of nonproportional loading and residual stress on creep crack tip fields . | ENGINEERING FRACTURE MECHANICS , 2023 , 281 . |
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Abstract :
发展高可靠的互连封装新型焊料已经成为电子封装领域的前沿研究内容之一.本文制备了包镍碳纳米管增强SAC305焊料,并开展了不同含量增强SAC305焊料的双悬臂梁试样Ⅰ型断裂测试,得到了不同添加含量SAC305的载荷-位移曲线.基于柔度的梁方法理论(CBBM)计算了增强焊料的Ⅰ型断裂韧度.研究结果表明,其Ⅰ型断裂韧度随着包镍碳纳米管质量分数的增加,表现出先升高后降低的趋势.没有添加包镍碳纳米管的SAC305焊料的Ⅰ型断裂韧度约为0.53N/mm,添加0.05wt%包镍碳纳米管的增强焊料的Ⅰ型断裂韧度最高,约为1.14 N/mm,相较于没有添加包镍碳纳米管的SAC305焊料断裂韧度提高了 1.15倍,表现出更好的抵抗裂纹扩展的特性.
Keyword :
断裂 断裂 包镍碳纳米管 包镍碳纳米管 双悬臂梁试样 双悬臂梁试样 能量释放率 能量释放率 SAC305焊料 SAC305焊料
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GB/T 7714 | 张谋 , 秦飞 , 代岩伟 . 包镍多壁碳纳米管增强SAC305焊料的Ⅰ型断裂机理研究 [J]. | 微电子学与计算机 , 2023 , 40 (1) : 124-129 . |
MLA | 张谋 et al. "包镍多壁碳纳米管增强SAC305焊料的Ⅰ型断裂机理研究" . | 微电子学与计算机 40 . 1 (2023) : 124-129 . |
APA | 张谋 , 秦飞 , 代岩伟 . 包镍多壁碳纳米管增强SAC305焊料的Ⅰ型断裂机理研究 . | 微电子学与计算机 , 2023 , 40 (1) , 124-129 . |
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Abstract :
In this paper, the elastoplastic and creep constitutive behaviors of sintered silver with varying amounts of nickel-modified multiwall carbon nanotubes are studied through a systematic investigation of the nanoindentation test. Elastoplastic stress-strain curves for the sintered silver with different additive content are obtained based on reverse analysis. The addition of nickel-modified multiwall carbon nanotubes reduced the yielding stress from 110.68 MPa to 61.61 MPa and generally increased the strain-hardening exponent from 0.26 to 0.41. The initial and steady-state creep stress exponent remained almost unchanged. However, the creep coefficient increased remarkably. Otherwise, the yielding stress was confirmed to agree well with the Hall-Petch relation, and the hardening exponent was found to follow Morrison's law. The creep exponents and creep coefficients were also obtained and shown to be highly related to the particle size and positively correlated with porosity. The creep regime at room temperature was confirmed to obey Sherby's model. This investigation shows the effect of additive content on sintered silver. The study given in this paper could deepen the understanding of the strengthening effect of nickel-modified multiwall carbon nanotubes on the mechanical performance of sintered silver at room temperature.
Keyword :
nanoindentation nanoindentation Sintered Ag Sintered Ag elastoplasticity elastoplasticity creep creep nickel-modified multiwall carbon nanotubes nickel-modified multiwall carbon nanotubes
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GB/T 7714 | Dai, Yanwei , Zan, Zhi , Zhao, Libo et al. Nanoindentation Elastoplastic and Creep Behaviors of Sintered Nano-Silver Doped with Nickel-Modified Multiwall Carbon Nanotube Filler [J]. | JOURNAL OF ELECTRONIC MATERIALS , 2023 , 53 (3) : 1344-1359 . |
MLA | Dai, Yanwei et al. "Nanoindentation Elastoplastic and Creep Behaviors of Sintered Nano-Silver Doped with Nickel-Modified Multiwall Carbon Nanotube Filler" . | JOURNAL OF ELECTRONIC MATERIALS 53 . 3 (2023) : 1344-1359 . |
APA | Dai, Yanwei , Zan, Zhi , Zhao, Libo , Qin, Fei . Nanoindentation Elastoplastic and Creep Behaviors of Sintered Nano-Silver Doped with Nickel-Modified Multiwall Carbon Nanotube Filler . | JOURNAL OF ELECTRONIC MATERIALS , 2023 , 53 (3) , 1344-1359 . |
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Abstract :
A fatigue crack growth rate model introducing corrosion damage is proposed in this paper, where the fracture parameter is modified by the damage variable and the exponential influence factor. The corrosion damage mechanism is coupled to the crack growth rate model, which quantifies the influence of the environment and reflects the interaction between corrosion and fatigue. To accurately predict the corrosion-fatigue crack growth life by the extended finite element method (XFEM), a simple crack surface updating method is developed. This method does not depend on the complex level set marching algorithm which often brings serious computational convergence problem, so it has good robustness and high efficiency. Moreover, the stress intensity factors at arbitrary crack tip can be calculated by combining the interaction integral method and the piecewise interpolation method, so it is suitable for the double crack-tip problem. The corrosionfatigue crack growth life is calculated based on the cycle-by-cycle method and the corresponding algorithm is developed. The corrosion-fatigue crack growth life can be accurately predicted by calculating the corrosion damage and crack propagation length under each load cycle. In this paper, sufficient examples are given to verify the accuracy of the proposed method in simulating crack propagation path and predicting corrosion-fatigue life. Finally, this method is well applied to a practical engineering structure.
Keyword :
Extended finite element method Extended finite element method Crack growth rate model Crack growth rate model Fatigue life calculation Fatigue life calculation Corrosion damage Corrosion damage Crack surface update Crack surface update
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GB/T 7714 | Chen, Zhiying , Dai, Yanwei , Liu, Yinghua . Life prediction of corrosion-fatigue based on a new crack growth rate model with damage and the extended finite element method [J]. | ENGINEERING FRACTURE MECHANICS , 2023 , 289 . |
MLA | Chen, Zhiying et al. "Life prediction of corrosion-fatigue based on a new crack growth rate model with damage and the extended finite element method" . | ENGINEERING FRACTURE MECHANICS 289 (2023) . |
APA | Chen, Zhiying , Dai, Yanwei , Liu, Yinghua . Life prediction of corrosion-fatigue based on a new crack growth rate model with damage and the extended finite element method . | ENGINEERING FRACTURE MECHANICS , 2023 , 289 . |
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