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Aoshuang Wan Junjiang Xiong Yigeng Xu 《Fatigue & Fracture of Engineering Materials & Structures》2020,43(9):2130-2146
An engineering approach for fatigue life prediction of fibre‐reinforced polymer composite materials is highly desirable for industries due to the complexity in damage mechanisms and their interactions. This paper presents a fatigue‐driven residual strength model considering the effect of initial delamination size and stress ratio. Static and constant amplitude fatigue tests of woven composite specimens with delamination diameters of 0, 4 and 6 mm were carried out to determine the model parameters. Good agreement with experimental results has been achieved when the modified residual strength model has been applied for fatigue life prediction of the woven composite laminate with an initial delamination diameter of 8 mm under constant amplitude load and block fatigue load. It has been demonstrated that the residual strength degradation‐based model can effectively reflect the load sequence effect on fatigue damage and hence provide more accurate fatigue life prediction than the traditional linear damage accumulation models. 相似文献
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W.‐B. Shangguan T.‐K. Liu X.‐L. Wang C. Xu B. Yu 《Fatigue & Fracture of Engineering Materials & Structures》2014,37(6):623-636
A method for modelling fatigue life of rubbers and rubber isolators is presented in this paper. Firstly, a fatigue experiment is carried out for a rubber dumbbell cylindrical specimen and a rubber isolator. Based on the finite element analysis, the damage parameters including the strain energy density, the maximum principal Green–Lagrange strain and the effective stress are calculated and discussed. Secondly, three fatigue life prediction models are established by using the three damage parameters and using the relation between the measured fatigue life of a dumbbell cylindrical specimen and the computed value of the damage parameters. Thirdly, three proposed prediction models are used to investigate which one can be best used to predicting fatigue life of rubber isolators, taking a typical powertrain rubber isolator as studying example. The fatigue lives of the rubber isolator predicted by the three models are compared with the experimental life. The results demonstrate that the predicted fatigue lives of the rubber isolator using the three fatigue models agree well with the experimental fatigue life within a factor of four, and the model using the effective stress as the damage parameter can predict the fatigue life within a factor of two, which has the best accuracy among the three models. 相似文献
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多轴载荷下缺口件的疲劳寿命估算方法 总被引:4,自引:0,他引:4
提出了一种多轴载荷下缺口件的疲劳寿命估算方法。该方法基于临界平面理论,计算出缺口件各部位的多轴疲劳损伤参数,以损伤参数最大的部位为缺口件的多轴疲劳危险点。根据临界距离思想,提出了热点法和线法的临界距离的计算方法,采用热点法和线法考虑缺口件疲劳危险点附近损伤梯度的影响,以临界距离修正的损伤参数计算多轴载荷下缺口件的疲劳寿命。采用SAE1045钢缺口件的多轴疲劳试验对该文提出的寿命估算方法进行评估和验证,结果表明:该文所建立的寿命预测方法具有较好的预测能力,预测结果大部分分布在试验结果的3倍分散带之内。 相似文献
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An improved damage model using the construction technology of virtual load spectrum and its statistical analysis
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N.H. Ye Y. He X. Deng C.C. Cheng 《Fatigue & Fracture of Engineering Materials & Structures》2018,41(8):1706-1716
In this work, an improved damage model based on construction technology of virtual load spectrum is developed. A predetermined reliability index is used as the termination criterion to calculate the fatigue life, and the results of statistical analysis have shown that the accuracy of fatigue life prediction result has been greatly improved. The model is targeting cyclic loading applications. The main advantage of the model is the use of construction technology of virtual load spectrum for expanding load spectrum and the Monte Carlo method for correcting fatigue damage. Another advantage concerns the link between predetermined reliability criterion and the fatigue life, which puts forward a new method of calculating fatigue life. The convergence proof of the model is presented, and physical experiment data are shown for validation. Several illustrative examples are presented to confirm the accuracy and efficiency of the proposed damage model. 相似文献
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针对冲击后复合材料层合板, 发展了含冲击初始损伤层合板的压-压疲劳寿命预测方法。该方法基于无损单向板的力学性能和疲劳特性, 对不同铺层参数、 不同几何尺寸以及不同冲击条件下层合板的疲劳寿命进行预测。为消除人为假设冲击损伤造成的误差, 对层合板在冲击载荷及冲击后疲劳载荷作用下的破坏进行全程分析, 即把冲击后层合板的实际损伤状态直接作为疲劳分析的初始状态。同时基于逐渐损伤思想, 推导了含冲击初始损伤层合板的应力分析过程, 建立了相应的三维逐渐累积损伤模型, 开发了参数化的复合材料层合结构冲击及冲击后疲劳破坏模拟程序, 为复合材料层合结构的抗冲击设计及其疲劳损伤扩展行为研究提供了较好的技术平台。 相似文献
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聚酰亚胺无机杂化薄膜疲劳性能研究 总被引:2,自引:0,他引:2
现有报道较少涉及有机薄膜疲劳特性的研究。基于应力幅控制,对聚酰亚胺/二氧化硅(PI/SiO_2)复合薄膜的疲劳性能进行了实验研究,给出了不同应力幅值下材料的疲劳寿命,以及阻尼角、储能模量、耗能模量等随疲劳周次增加的变化规律。在此基础上,基于疲劳模量的概念,提出了一种改进型的针对聚合物及基体控制聚合物复合材料的疲劳寿命预测模型,其理论预测值与实验测试结果具有很好的一致性。 相似文献
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多孔试件在热循环下的复合疲劳的损伤特性研究 总被引:1,自引:0,他引:1
根据航空发动机工作叶片实际工作中的载荷环境,即气冷叶片承受低周的离心力负荷,气动载荷及温度负荷,同时还叠加高弯曲振动载荷,进行了一系列热循环下复合疲劳和常温机械疲劳的组合试验,在试验研究基础上提出复合疲劳中耦合损伤的概念及分析, 相似文献
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Cumulative damage model based on equivalent fatigue under multiaxial thermomechanical random loading
Luo‐Jin Li De‐Guang Shang Dao‐Hang Li Long Xue Xiao‐Dong Liu Xiang Yin Cheng‐Cheng Zhang Bo Chen 《Fatigue & Fracture of Engineering Materials & Structures》2020,43(8):1851-1868
A new creep–fatigue damage cumulative model is proposed under multiaxial thermomechanical random loading, in which the damage at high temperature can be divided into the pure fatigue damage and the equivalent fatigue damage from creep. During the damage accumulation process, the elementary percentage of the equivalent fatigue damage increment is proportional to that of the creep damage increment, and the creep damage is converted to the equivalent fatigue damage. Moreover, combined with a multiaxial cyclic counting method, a life prediction method is developed based on the proposed creep–fatigue damage cumulative model. In the developed life prediction method, the effects of nonproportional hardening on the fatigue and creep damages are considered, and the influence of mean stress on damage is also taken into account. The thermomechanical fatigue experimental data for thin‐walled tubular specimen of superalloy GH4169 under multiaxial constant amplitude and variable amplitude loadings were used to verify the proposed model. The results showed that the proposed method can obtain satisfactory life prediction results. 相似文献
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H. CHEN D.‐G. SHANG E.‐T. LIU 《Fatigue & Fracture of Engineering Materials & Structures》2011,34(10):782-791
A path‐dependent cycle counting method is proposed by applying the distance formula between two points on the tension‐shear equivalent strain plane for the identified half‐cycles first. The Shang–Wang multiaxial fatigue damage model for an identified half‐cycle and Miner's linear accumulation damage rule are used to calculate cumulative fatigue damage. Therefore, a multiaxial fatigue life prediction procedure is presented to predict conveniently fatigue life under a given tension and torsion random loading time history. The proposed method is evaluated by experimental data from tests on cylindrical thin‐walled tubes specimens of En15R steel subjected to combined tension/torsion random loading, and the prediction results of the proposed method are compared with those of the Wang–Brown method. The results showed that both methods provided satisfactory prediction. 相似文献
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A theoretical method for the prediction of fatigue life of structural members containing external stress raisers has been developed. The method is based on a linear elastic fracture mechanics approach to fatigue. The theory has been applied to fatigue of Torbar steel in concrete beams. The required parameters for such application were obtained from fatigue tests on samples and finite element analysis of cracked bars. Comparisons between the theory and experimental data taken from other investigations have shown that the theory predicts a reasonable lower limit fatigue life of Torbar in concrete beams. The theory has also successfully predicted the effect of the minimum stress on the fatigue life of this type of bar. 相似文献
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介绍了船体结构中含缺陷的焊接接头完整性评估以及疲劳寿命预测方法,对结构完整性评估的K准则、COD准则、J积分准则、SINTAP/FITNET安全性评定方法以及评定流程、国内外标准进行介绍。并对焊接接头的疲劳强度影响因素,如平均应力、残余应力以及接头几何形状应力集中等进行了分析;介绍了焊接接头疲劳寿命预测的常用方法,如基于名义应力的评估方法、基于断裂力学的评估方法、基于损伤力学的评估方法以及其它疲劳评估方法等。此外,还对基于断裂力学法建立的焊接残余应力与疲劳裂纹扩展寿命之间的函数关系进行了介绍,该方法实现了对含残余应力的焊接结构疲劳寿命的精确预测。 相似文献
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Elastomeric components have wide usage in many industries. The typical service loading for most of these components is variable amplitude and multiaxial. In this study a general methodology for life prediction of elastomeric components under these typical loading conditions was developed and illustrated for a passenger vehicle cradle mount. Crack initiation life prediction was performed using different damage criteria. The methodology was validated with component testing under different loading conditions including constant and variable amplitude in-phase and out-of-phase axial–torsion experiments. The optimum method for crack initiation life prediction for complex multiaxial variable amplitude loading was found to be a critical plane approach based on maximum normal strain plane and damage quantification by cracking energy density on that plane. Rainflow cycle counting method and Miner’s linear damage rule were used for predicting fatigue life under variable amplitude loadings. The fracture mechanics approach was used for total fatigue life prediction of the component based on specimen crack growth data and FE simulation results. Total fatigue life prediction results showed good agreement with experiments for all of the loading conditions considered. 相似文献
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为了准确地预测橡胶沥青混合料的疲劳寿命(Nf),分析Nf与劲度模量衰减量(SMD)、劲度模量衰减量相对变化率(SMDR)的相关性,根据累积劲度模量衰减量相对变化率(CSMDR)分别建立了其与疲劳荷载次数的函数关系式和损伤模型,基于SMDR与损伤演化速率的相关性分析建立了疲劳方程。结果表明:应用SMD不能很好地预测Nf,SMDR表征了产生损伤变形的劲度模量衰减量占总衰减量的比例,可用于损伤演化分析和Nf预测;建立的函数关系式和损伤模型能分别准确地刻画CSMDR的变化特征和非线性损伤演化规律;建立的疲劳方程能准确地预测橡胶沥青混合料的Nf。 相似文献
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以某5 MW特大型风力机为例,提出了风力机全机结构风振疲劳的时域分析方法。采用谐波合成法和改进的叶素-动量理论产生了风力机运营状态的气动载荷,对风力机塔架-叶片耦合结构进行了非线性风振时域分析。基于时程结果并结合线性累积损伤理论对风力机全机关键部位的风振疲劳寿命进行了预测,该方法充分考虑了风剪切、塔影、尾流影响、塔架-叶片之间的气动和模态干扰作用、叶片旋转效应的影响。算例分析表明,该文预测方法可有效估算水平轴风力机全机结构的疲劳损伤问题,相关研究结论可为超大型风力机全机结构的疲劳寿命预测提供科学依据。 相似文献
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锻锤基础的冲击疲劳损伤分析 总被引:3,自引:0,他引:3
用损伤力学的概念提出了一种研究由锻锤锻打引起锻锤基础系统的疲劳损伤增长和疲劳寿命估计的方法。该方法通过定义,引入锻锤基础系统中减振垫与基础块的损伤状态寿命因子,能够估计出锻锤基础系统的减振垫和基础块的损伤疲劳寿命上、下限。通过分析发现,长期的重复冲击载荷会引起锻锤基础系统发生疲劳微损伤积累,疲劳损伤积累的宏观损伤又引起锻锤基础的动力响应随宏观损伤发展而增大,动力响应的增大又加剧基础系统的损伤发展。因此,为减少周围环境的振动以及保护周围环境免受锻锤冲击损伤,在锻锤基础系统设计中需考虑吸振和损伤控制。 相似文献
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A simple energy‐based model for nonproportional low‐cycle multiaxial fatigue life prediction under constant‐amplitude loading
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From the literature concerning the traditional nonproportional (NP) multiaxial cyclic fatigue prediction, special attentions are usually paid to multiaxial constitutive relations to quantify fatigue damage accumulation. As a result, estimation of NP hardening effect decided by the entire history path is always proposed, which is a challenging and complex task. To simplify the procedure of multiaxial fatigue life prediction of engineering components, in this paper, a novel effective energy parameter based on simple material properties is proposed. The parameter combines uniaxial cyclic plastic work and NP hardening effects. The fatigue life has been assessed based on traditional multiaxial fatigue criterion and the proposed parameter, which has been validated by experimental results of 316 L stainless steel under different low‐cycle loading paths. 相似文献
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A hybrid frequency–time domain method for predicting multiaxial fatigue life of 7075‐T6 aluminium alloy under random loading
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J. Ge Y. Sun S. Zhou L. Zhang Y. Zhang Q. Zhang 《Fatigue & Fracture of Engineering Materials & Structures》2015,38(3):247-256
A hybrid frequency–time domain method for predicting multiaxial fatigue life under random loading is developed on the basis of combination of the frequency domain and time domain analysis. The critical damage point of the structure is determined by the frequency domain equivalent stress method. Then, the fatigue life prediction is made in time domain by generating random load‐time histories from the power spectral density of the critical point. The method is validated with the random vibration fatigue test of 7075‐T6 aluminium alloy. It has been shown that the results of fatigue life calculated by hybrid method are well correlated with the experiment. 相似文献