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Critical plane-based fatigue life model under multiaxial random loading 多轴随机载荷下基于临界平面的疲劳寿命模型
IF 2.7 Pub Date : 2022-08-08 DOI: 10.1108/ijsi-06-2022-0083
Jie Wang, Jianhui Liu, Feilong Hua, Yingbao He, Xuexue Wang
PurposeEngineering components/structures are usually subjected to complex and variable loads, which result in random multiaxial stress/strain states. However, fatigue analysis methods under constant loads cannot be directly applied to fatigue life prediction analysis under random loads. Therefore, the purpose of this study is how to effectively evaluate fatigue life under multiaxial random loading.Design/methodology/approachFirst, the average phase difference is characterized as the ratio of the number of shear strain cycles to the number of normal strain cycles, and the new non-proportional additional hardening factor is proposed. Then, the determined random typical load spectrum is processed into a simple variable amplitude load spectrum, and the damage in each plane is calculated according to the multiaxial fatigue life prediction model and Miner theory. Meanwhile, the cumulative damage can be calculated separately by projection method. Finally, the maximum projected cumulative damage plane is defined as the critical plane of multiaxial random fatigue.FindingsThe fatigue life prediction capability of the method is verified based on test data of TC4 titanium alloy under random multiaxial loading. Most of the predicting results are within double scatter bands.Originality/valueThe objective of this study is to provide a reference for the determination of critical plane and non-proportional additional hardening factor under multiaxial random loading, and to promote the development of multiaxial fatigue from experimental studies to practical engineering applications.
工程构件/结构通常承受复杂多变的载荷,导致随机多轴应力/应变状态。然而,恒载荷下的疲劳分析方法不能直接应用于随机载荷下的疲劳寿命预测分析。因此,如何有效地评估多轴随机载荷下的疲劳寿命是本研究的目的。设计/方法/方法首先,将平均相位差表征为剪切应变循环数与正常应变循环数之比,并提出了新的非比例附加硬化因子。然后,将确定的随机典型载荷谱处理成简单的变幅载荷谱,并根据多轴疲劳寿命预测模型和Miner理论计算各平面的损伤;同时,利用投影法对累积损伤进行单独计算。最后,将最大投影累积损伤面定义为多轴随机疲劳临界面。结果基于TC4钛合金随机多轴载荷试验数据,验证了该方法的疲劳寿命预测能力。大多数预测结果在双散射带内。本研究旨在为多轴随机载荷下临界平面和非比例附加硬化系数的确定提供参考,推动多轴疲劳研究从实验研究向实际工程应用发展。
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引用次数: 4
Uncertainty analysis of varied meshes of a finite element model using Monte Carlo simulation 有限元模型变网格的蒙特卡罗模拟不确定度分析
IF 2.7 Pub Date : 2022-08-05 DOI: 10.1108/ijsi-02-2022-0020
Mohamad Syazwan Zafwan Mohamad Suffian, Syahiir Kamil, A. Ariffin
PurposeAdvanced computational methods help to solve complex engineering problems via finite-element simulation. However, uncertainties during the process occurred due to the nature of geometry, material properties, loading, and boundary conditions. These inaccuracies affect the accuracy of results obtained from the analysis. This paper aims to analyse the uncertainty parameters of a finite element model in Excel-Visual Basic Application (VBA) by applying a random simulation method.Design/methodology/approachThis study focuses on a finite element model with a different mesh. Young's Modulus, E, Poisson's ratio, and load, L are the uncertainty input parameters considered random variables.FindingsResults obtained proved that the finite element model with the most nodes and elements has better solution convergence.Originality/valueRandom simulation method is a tool to perform uncertainty analysis of a finite element model.
目的先进的计算方法有助于通过有限元模拟解决复杂的工程问题。然而,由于几何形状、材料特性、载荷和边界条件的性质,在此过程中存在不确定性。这些误差影响了分析所得结果的准确性。本文采用随机仿真的方法,对Excel-Visual Basic Application (VBA)中某有限元模型的不确定性参数进行了分析。设计/方法/方法本研究侧重于具有不同网格的有限元模型。杨氏模量E、泊松比和载荷L是考虑随机变量的不确定性输入参数。结果表明,节点和单元数最多的有限元模型具有较好的解收敛性。独创性/价值随机模拟方法是一种对有限元模型进行不确定性分析的工具。
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引用次数: 1
Failure behaviors of 34Cr2Ni2Mo steel up to very high-cycle fatigue 34Cr2Ni2Mo钢高周疲劳失效行为
IF 2.7 Pub Date : 2022-08-02 DOI: 10.1108/ijsi-06-2022-0082
Shijian Wang, Qiyuan He, Quanwei Liang, J. Cui, Q. Jiang, Chang Liu, C. He, Lang Li, Yao Chen
PurposeThe study aims to examine the effect of inclusions and inherent microstructure on fatigue behavior of 34Cr2Ni2Mo steel.Design/methodology/approachFatigue behavior of 34Cr2Ni2Mo steel was investigated for up to 1E10 cycles.FindingsResults showed that both inclusion and inherent microstructure have an influence on the crack initiation mechanism. Fatigue cracks mostly initiated from inclusions, whereas substrate-induced crack initiations were also observed. Fatigue life of inclusion-induced failures is mostly determined by the location of inclusions rather than the loading stress. The inherent microstructure seems to tolerate inclusions at a lower stress level in very high-cycle regime owing to the absence of internal inclusion-induced failure. For the substrate-induced crack initiations, high-density dislocations are found to be accumulated around the carbide particle-matrix interface, which may be the cause of crack initiation in the inherent structure due to strain localization.Originality/valueThe effect of inclusions and inherent microstructure on fatigue behavior of 34Cr2Ni2Mo steel up to 1E10 cycles.HighlightsFatigue failure occurs even at a lifetime of 5.76E9 cycles.Surface inclusion induced premature failures.Inherent microstructure tolerates inclusions at lower stress level.Internal carbides promote substrate-induced crack initiations.
目的研究夹杂物和固有组织对34Cr2Ni2Mo钢疲劳性能的影响。设计/方法/方法研究了34Cr2Ni2Mo钢在1E10次循环下的疲劳行为。结果表明,夹杂物和固有组织都对裂纹的起裂机制有影响。疲劳裂纹主要由夹杂物引起,但也有基体引起的裂纹。夹杂物诱发失效的疲劳寿命主要取决于夹杂物的位置而不是载荷应力。由于没有内部夹杂引起的破坏,在非常高的循环状态下,固有的微观结构似乎可以在较低的应力水平下容忍夹杂物。在基体诱导裂纹萌生过程中,碳化物颗粒-基体界面周围聚集了高密度的位错,这可能是由于应变局部化导致固有结构裂纹萌生的原因。研究了夹杂物和固有组织对34Cr2Ni2Mo钢1E10次循环疲劳性能的影响。即使寿命为5.76E9次,也会发生疲劳失效。表面夹杂物导致过早失效。固有的微观结构在较低的应力水平下可以容忍夹杂物。内部碳化物促进基体诱导裂纹萌生。
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引用次数: 1
Heterogeneous deformation of friction stir welded aluminum alloy 6061 in tension and high cycle fatigue 搅拌摩擦焊接6061铝合金在拉伸和高周疲劳下的非均匀变形
IF 2.7 Pub Date : 2022-07-21 DOI: 10.1108/ijsi-06-2022-0079
Y. Dai, Chang Liu, M. Zhan, Xiangyu Wang, C. He, Qingyuan Wang
PurposeThe investigations provide a basis for the optimization of the alloy 6061-T6 friction stir welding (FSW) process to improve the mechanical properties of welded joints.Design/methodology/approachThe local deformation of the FSW joint in tension and fatigue test were experimentally investigated by digital image correlation (DIC) technique.FindingsThe local stress-strain behaviors of the sub-regions show that the plastic strain always concentrated at the heat affected zone (HAZ) on the advancing side both in tension and high cycle fatigue and eventually leads to the final fracture. The evolution of the plastic strain at very low stress is extremely slow and accounts for most of the total fatigue life. However, the local deformation exhibits a sudden increase just before the fatigue failure.Originality/valueBased on the experimental data, the result indicates that the HAZ is the weakest zone across the weld and the strain localization in high cycle fatigue is very harmful and unpredictable for the FSW joints.
目的为优化6061-T6合金搅拌摩擦焊工艺以提高焊接接头的力学性能提供依据。设计/方法/方法利用数字图像相关(DIC)技术对FSW接头在拉伸和疲劳试验中的局部变形进行了实验研究。结果表明,无论是在拉伸还是高周疲劳中,塑性应变总是集中在前进侧的热影响区,最终导致断裂。塑性应变在非常低的应力下的演变非常缓慢,并且占总疲劳寿命的大部分。然而,就在疲劳失效之前,局部变形表现出突然增加。原创性/价值基于实验数据,结果表明HAZ是整个焊缝的最弱区域,高周疲劳中的应变局部化对FSW接头来说是非常有害和不可预测的。
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引用次数: 0
Vibrations of a vertical 90° pipe bend under two-phase flow conditions 两相流条件下垂直90°弯管的振动
IF 2.7 Pub Date : 2022-07-19 DOI: 10.1108/ijsi-03-2022-0028
Shah Danial Shah Reza, M. Rasani
PurposeA simulation framework that includes a finite element analysis (FEA) and computational fluid dynamics (CFD) model is generated to study the effect of unstable two-phase flow-induced vibrations at a vertical 90° pipe bend. The corresponding fluid-structure interaction (FSI) of an unstable flow may pose danger to the piping structure. This paper intends to discuss this interaction.Design/methodology/approachFour cases of flows under the slug flow and churn flow regimes were investigated. The flow regimes vary in superficial gas velocities with velocities from 0.978 m/s to 9.04 m/s, while the superficial liquid velocity is kept constant at 0.61 m/s. The pipe model consists of an internal diameter of 0.0525 m, a bend radius of 0.0762 m, and a stainless-steel pipe structure.FindingsResults show that the average unstable void fractions increase with the superficial gas velocities, but the peak frequencies were constant at 13 Hz for three of the cases. The total displacement and von Mises stress increase with a declining rate in each subsequent case, while the RMS of von Mises stress begins to stall at superficial gas velocities between 5 m/s and 9.04 m/s. The peak frequencies of von Mises stress decrease in each subsequent case.Originality/valueThe proposed model can be used to investigate the FSI effect of unstable void fractions at pipe bends and could assist in the development of piping systems in which the use of piping elements arranged close together are unavoidable.
目的生成一个包括有限元分析(FEA)和计算流体动力学(CFD)模型的模拟框架,以研究垂直90°弯管处不稳定两相流引起的振动的影响。不稳定流动的相应流体-结构相互作用(FSI)可能对管道结构构成危险。本文旨在探讨这种互动关系。设计/方法/方法研究了段塞流和搅拌流状态下的四种流动情况。流动状态的表观气体速度在0.978 m/s至9.04 m/s之间变化,而表观液体速度保持恒定在0.61 m/s。管道模型由内径0.0525 m、弯曲半径0.0762 m和不锈钢管道结构组成。结果表明,平均不稳定空隙率随着表观气体速度的增加而增加,但其中三种情况的峰值频率恒定在13Hz。在随后的每种情况下,总位移和von Mises应力都会以下降的速度增加,而von Misers应力的RMS在5 m/s和9.04 m/s之间的表观气体速度下开始失速。在随后的每个情况下,von Mises应力的峰值频率都会降低。独创性/价值所提出的模型可用于研究弯管处不稳定空隙率的FSI效应,并有助于开发不可避免地使用紧密排列的管道元件的管道系统。
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引用次数: 0
Structural dynamic reliability analysis: review and prospects 结构动力可靠性分析:回顾与展望
IF 2.7 Pub Date : 2022-07-08 DOI: 10.1108/ijsi-04-2022-0050
D. Teng, Yunwen Feng, Jun-Yu Chen, Cheng Lu
PurposeThe purpose of this paper is to briefly summarize and review the theories and methods of complex structures’ dynamic reliability. Complex structures are usually assembled from multiple components and subjected to time-varying loads of aerodynamic, structural, thermal and other physical fields; its reliability analysis is of great significance to ensure the safe operation of large-scale equipment such as aviation and machinery.Design/methodology/approachIn this paper for the single-objective dynamic reliability analysis of complex structures, the calculation can be categorized into Monte Carlo (MC), outcrossing rate, envelope functions and extreme value methods. The series-parallel and expansion methods, multi-extremum surrogate models and decomposed-coordinated surrogate models are summarized for the multiobjective dynamic reliability analysis of complex structures.FindingsThe numerical complex compound function and turbine blisk are used as examples to illustrate the performance of single-objective and multiobjective dynamic reliability analysis methods. Then the future development direction of dynamic reliability analysis of complex structures is prospected.Originality/valueThe paper provides a useful reference for further theoretical research and engineering application.
目的对复杂结构动力可靠度的理论和方法进行简要的总结和评述。复杂结构通常由多个部件组装而成,并承受空气动力学、结构、热和其他物理场的时变载荷;其可靠性分析对保证航空、机械等大型设备的安全运行具有重要意义。设计/方法论/方法在本文中,复杂结构的单目标动力可靠性分析的计算可分为蒙特卡洛法、交叉率法、包络函数法和极值法。总结了用于复杂结构多目标动力可靠性分析的串并展开法、多极值代理模型和分解协调代理模型。以数值复变复合函数和涡轮叶盘为例,说明了单目标和多目标动力可靠性分析方法的性能。展望了复杂结构动力可靠性分析的未来发展方向。本文为进一步的理论研究和工程应用提供了有益的参考。
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引用次数: 22
Experimental study on performance of CFRP-strengthened RC beams with geopolymer and epoxy 地质聚合物和环氧树脂加固CFRP钢筋混凝土梁性能试验研究
IF 2.7 Pub Date : 2022-07-06 DOI: 10.1108/ijsi-05-2022-0065
Baocheng Liu, Jinliang Liu, Yanqian Wen, Qinglin Hu, Liang Liu, Shilin Zhao
PurposeIn this paper, to obtain shear and bending performance of carbon fiber-reinforced polymer (CFRP)-strengthened beams bonded by geopolymers, the effects of impregnated adhesive types, strengthened scheme, CFRP layer and pre-cracked width are investigated, and the performance of CFRP-strengthened beams is validated by the establishment of Finite Element Models (FEMs).Design/methodology/approachIn this paper, static loading test and finite element analysis of epoxy-CFRP-strengthened (ECS) and geopolymer-CFRP-strengthened (GCS) were carried out, and the bearing capacity and stiffness were compared, the results show that GCS reinforced concrete (RC) beam is feasible and effective.FindingsThe bearing capacity, crack distribution and development, load–deflection curves of GCS RC beams with different pre-crack widths were investigated. The reinforcement effect of geopolymer achieves the same as epoxy, effectively improving the ultimate bearing capacity of the beam, with a maximum increase rate of 28.9%. The failure mode of CFRP is broken in the yield failure stage of GCS RC beam with reasonable strengthening form, and the utilization rate of CFRP is improved. CFRP-strengthened layers, pre-cracked widths significantly affect the mechanical properties, and deformation properties of the strengthened beams.Originality/valueCompared with ECS RC beams, the bearing capacity and stiffness of GCS RC beams are similar to or even better, indicating that GCS RC beam is feasible and effective. It is a new method for CFRP-strengthened beams, which not only conforms to the concept of national ecological civilization construction, but also provides an economical, environmentally friendly and excellent performance solution for structural reinforcement.
目的为了获得地质聚合物粘结碳纤维增强聚合物(CFRP)加固梁的抗剪和抗弯性能,研究了浸渍胶类型、加固方案、CFRP层和预裂宽度的影响,并通过建立有限元模型(FEM)对CFRP加固梁的性能进行了验证。设计/方法/方法本文对环氧CFRP加固(ECS)和地质聚合物CFRP增强(GCS)进行了静载试验和有限元分析,并对其承载力和刚度进行了比较,结果表明,GCS型钢筋混凝土梁是可行和有效的。研究了不同预裂宽度的GCS RC梁的承载力、裂缝分布和发展、荷载-挠度曲线。地质聚合物的加固效果达到了与环氧树脂相同的效果,有效地提高了梁的极限承载力,最大提高率为28.9%。通过合理的加固形式,在GCS RC梁的屈服破坏阶段打破了CFRP的破坏模式,提高了CFRP利用率。CFRP加固层、预裂宽度对加固梁的力学性能和变形性能有显著影响。独创性/价值与ECS RC梁相比,GCS RC梁的承载力和刚度与ECS RC梁相差无几,甚至更好,表明GCS RC梁可行且有效。它是碳纤维布加固梁的一种新方法,不仅符合国家生态文明建设的理念,而且为结构加固提供了一种经济、环保、性能优异的解决方案。
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引用次数: 1
Multidisciplinary design optimization of engineering systems under uncertainty: a review 不确定条件下工程系统多学科设计优化研究综述
IF 2.7 Pub Date : 2022-07-05 DOI: 10.1108/ijsi-05-2022-0076
Debiao Meng, S. Yang, Chao He, Hongtao Wang, Zhiyuan Lv, Yipeng Guo, P. Nie
PurposeAs an advanced calculation methodology, reliability-based multidisciplinary design optimization (RBMDO) has been widely acknowledged for the design problems of modern complex engineering systems, not only because of the accurate evaluation of the impact of uncertain factors but also the relatively good balance between economy and safety of performance. However, with the increasing complexity of engineering technology, the proposed RBMDO method gradually cannot effectively solve the higher nonlinear coupled multidisciplinary uncertainty design optimization problems, which limits the engineering application of RBMDO. Many valuable works have been done in the RBMDO field in recent decades to tackle the above challenges. This study is to review these studies systematically, highlight the research opportunities and challenges, and attempt to guide future research efforts.Design/methodology/approachThis study presents a comprehensive review of the RBMDO theory, mainly including the reliability analysis methods of different uncertainties and the decoupling strategies of RBMDO.FindingsFirst, the multidisciplinary design optimization (MDO) preliminaries are given. The basic MDO concepts and the corresponding mathematical formulas are illustrated. Then, the procedures of three RBMDO methods with different reliability analysis strategies are introduced in detail. These RBMDO methods were proposed for the design optimization problems under different uncertainty types. Furtherly, an optimization problem for a certain operating condition of a turbine runner blade is introduced to illustrate the engineering application of the above method. Finally, three aspects of future challenges for RBMDO, namely, time-varying uncertainty analysis; high-precision surrogate models, and verification, validation and accreditation (VVA) for the model, are discussed followed by the conclusion.Originality/valueThe scope of this study is to introduce the RBMDO theory systematically. Three commonly used RBMDO-SORA methods are reviewed comprehensively, including the methods' general procedures and mathematical models.
基于可靠性的多学科设计优化(RBMDO)作为一种先进的计算方法,在现代复杂工程系统的设计问题中得到了广泛的认可,不仅因为它能准确地评估不确定因素的影响,而且在性能的经济性和安全性之间取得了相对较好的平衡。然而,随着工程技术的日益复杂,所提出的RBMDO方法逐渐不能有效解决高非线性耦合多学科不确定性设计优化问题,限制了RBMDO的工程应用。近几十年来,在RBMDO领域已经做了许多有价值的工作来应对上述挑战。本研究旨在对这些研究进行系统回顾,突出研究的机遇和挑战,并试图指导未来的研究工作。本研究对RBMDO理论进行了全面的综述,主要包括不同不确定性的可靠性分析方法和RBMDO的解耦策略。首先,对多学科设计优化(MDO)进行了初步研究。给出了MDO的基本概念和相应的数学公式。然后,详细介绍了采用不同可靠性分析策略的三种RBMDO方法的操作步骤。针对不同不确定性类型下的设计优化问题,提出了RBMDO方法。并以某水轮机转轮叶片在一定工况下的优化问题为例,说明了该方法的工程应用。最后,提出了RBMDO未来面临的三个方面挑战,即时变不确定性分析;讨论了高精度代理模型,以及模型的验证、验证和认可(VVA)。本研究的范围是系统地介绍RBMDO理论。综述了三种常用的RBMDO-SORA方法,包括方法的一般步骤和数学模型。
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引用次数: 48
Assessing the utilisation of industrial waste as aggregate and manufactured sand: microstructural and durability characteristics on high-performance concrete 评估工业废料作为骨料和人造砂的利用:高性能混凝土的微观结构和耐久性特征
IF 2.7 Pub Date : 2022-06-28 DOI: 10.1108/ijsi-03-2022-0034
Chandra Shekhar Reddy Kamasani, Sateesh Reddy Siddamreddy
PurposeUtilising industrial waste, such as fly ash (FA) and bagasse ash (BA), reduces waste management and increases mechanical strength. Concrete is modified with FA and BA in the cool bonded method of concrete preparation.Design/methodology/approachThe study used to partially replace cement with BA powder at proportions 0, 5, 10, 15, 20 and 25% and coarse aggregates are replaced with FA aggregates made with FA and cement using a cold-bonded technique at proportions 0–25%. FA aggregates were made at 10:90, 15:85, 20:80 and 25:75 proportions of cement and FA. The FA aggregates at the best proportion 15:85 was selected as a coarse aggregate by conducting tests like specific gravity, crushing value, impact value and water absorption tests.FindingsThe addition of 30% content decreases porosity by 21% and increases strength significantly at 28 days. Microstructure evolution is carried out to identify material behaviour.Originality/valueMechanical and durable properties such as flexural strength, tensile strength, water absorption test, acid and alkaline tests are conducted on M50 grade concrete after 3–28 days of curing.
目的利用工业废料,如粉煤灰和甘蔗渣灰,可以减少废物管理,提高机械强度。在混凝土制备的冷粘结法中,用FA和BA对混凝土进行改性。设计/方法/方法本研究用BA粉代替水泥,比例为0、5、10、15、20和25%,粗骨料用FA骨料代替,FA骨料和水泥采用冷粘合技术制成,比例为0 - 25%。水泥与FA的比例分别为10:90、15:85、20:80和25:75。通过比重、破碎值、冲击值、吸水率等试验,选择最佳配比15:85的FA骨料作为粗骨料。结果:添加30%的含量可使孔隙率降低21%,28 d强度显著提高。微观结构的演变是为了确定材料的行为。原创性/价值M50级混凝土在养护3-28天后进行抗弯强度、抗拉强度、吸水试验、酸碱试验等力学和耐用性能试验。
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引用次数: 0
Application of bird-strike verified analysis for the design of fast helicopter composite cowling 鸟击验证分析在快速直升机复合整流罩设计中的应用
IF 2.7 Pub Date : 2022-06-20 DOI: 10.1108/ijsi-10-2021-0113
R. Doubrava, M. Oberthor, P. Bělský, B. Cabrnoch
PurposeThe purpose of this paper is to describe the approach for the design of cowlings for a new fast helicopter from the perspective of airworthiness requirements regarding high-speed impact resistance.Design/methodology/approachValidated numerical simulation was applied to flat and simple curved test panels. High-speed camera measurement and non-destructive testing (NDT) results were used for verification of the numerical models. The final design was optimized and verified by validated numerical simulation.FindingsThe comparison between numerical simulation based on static material properties with experimental results of high-speed load shows no significant influence of strain rate effect in composite material.Research limitations/implicationsOwing to the sensitivity of the composite material on technology production, the results are limited by the material used and the production technology.Practical implicationsThe application of flat and simple curved test panels for the verification and calibration of numerical models allows the optimized final design of the cowling and reduces the risk of structural non-compliance during verification tests.Originality/valueNumerical models were verified for simulation of the real composite structure based on high-speed camera results and NDT inspection after impact. The proposed numerical model was simplified for application in a complex design and reduced calculation time.
目的从高速抗冲击适航要求的角度,介绍一种新型快速直升机整流罩的设计方法。设计/方法/方法验证的数值模拟应用于平面和简单弯曲的试验板。高速摄像机测量和无损检测(NDT)结果用于验证数值模型。通过验证的数值模拟对最终设计进行了优化和验证。结果基于材料静态特性的数值模拟与高速载荷实验结果的比较表明,复合材料中的应变速率效应没有显著影响。研究局限性/含义由于复合材料对技术生产的敏感性,结果受到所用材料和生产技术的限制。实际意义应用平面和简单弯曲的试验板来验证和校准数值模型,可以优化整流罩的最终设计,并降低验证试验期间结构不符合要求的风险。原创性/价值基于高速摄像机的结果和冲击后的无损检测,验证了用于模拟真实复合材料结构的数值模型。所提出的数值模型被简化以用于复杂的设计,并减少了计算时间。
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引用次数: 0
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International Journal of Structural Integrity
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