scholarly journals Influence of gap filling on mechanical properties of composite-aluminum single-lap single-bolt hybrid joints

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402198950
Author(s):  
Xuande Yue ◽  
Luling An ◽  
Zengtao Chen ◽  
Chufan Wang ◽  
Yuebo Cai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Damage Model ◽  
Peak Load ◽  
Middle Part ◽  
Gap Filling ◽  
Fiber Damage ◽  
Hybrid Joints ◽  
Matrix Shear ◽  
Progressive Damage Model ◽  
Matrix Damage

Composite-aluminum structures exist in aircraft structures generally. It is easy to cause gap between mating surfaces in composite-aluminum assembled structures with the curing deformation of composite. The composite-aluminum, single-lap, single-bolt joints were utilized to investigate the influence of forced assembly, liquid shim and peelable fiberglass shim on the mechanical properties of assembled structures. A steel gasket that removed the middle part was used in the joint to make a gap. The 3D Digital Imagine Correlation (3D-DIC) system was utilized to measure the strain field of specimens and the progressive damage model was created in ABAQUS. The results show that the shim filling can significantly increase the tension stiffness and peak load of the joint compare with forced assembly. As the shim thickness changes, the effects of the liquid shim and the peelable fiberglass shim on the tensile stiffness and peak load shows different. The liquid or peelable fiberglass shim can reduce the strain value around the hole and the peelable fiberglass shim has a better result than liquid shim. The squeeze between the bolt and composite laminate has a greater impact on matrix damage and fiber-matrix shear damage, while the secondary bending has a greater impact on matrix damage and fiber damage.

scholarly journals A progressive damage model of composite laminates under low-velocity impact

2021 ◽  
Vol 39 (1) ◽  
pp. 37-45
Author(s):  
Junjie Zhou ◽  
Shengnan Wang
Keyword(s):  
Composite Laminates ◽  
Impact Force ◽  
Damage Model ◽  
Low Velocity Impact ◽  
Progressive Damage ◽  
Low Velocity ◽  
Damage Development ◽  
Velocity Impact ◽  
Progressive Damage Model ◽  
Matrix Damage

In this paper, a progressive damage model for studying the dynamic mechanical response and damage development of composite laminates under low-velocity impact was established. The model applied the Hashin and Hou failure criteria to predict the initiation of intra-laminar damage (fiber and matrix damage); a linear degradation scheme combined with the equivalent displacement method was adopted to simulate the damage development; a cohesive zone model with the bilinear traction-separation relationship was used to predict delamination. A user material subroutine VUMAT was coded, and the simulation analysis of carbon fiber reinforcement composite laminates subjected to 25 J impact was performed via commercial software ABAQUS. The predicted impact force-time curve, impact force-displacement curve, and damage distribution contours among the layers were in a good agreement with the experimental, which verified the proposed model. According to the simulation results, the fiber damage and matrix damage were analyzed, and the expansion of delamination was discussed.

Prediction of Impact Damage of Composite Laminates Using a Mixed Damage Model

2014 ◽  
Vol 513-517 ◽  
pp. 235-237
Author(s):  
Shi Yang Zhao ◽  
Pu Xue
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Failure Modes ◽  
Impact Damage ◽  
Damage Model ◽  
Material Model ◽  
Element Model ◽  
Fiber Damage ◽  
Damage Process ◽  
Matrix Damage

In order to effectively describe the damage process of composite laminates and reduce the complexity of material model, a mixed damage model based on Linde Criteria and Hashin Criteria is proposed for prediction of impact damage in the study. The mixed damage model can predict baisc failure modes, including fiber fracture, matrix tensile damage, matrix compressive damage. Fiber damage and matrix damage in compression are described based on the progressive damage mechanics; and matrix damage in tension is described based on Continuous Damage Mechanics (CDM). Meanwhile, for interlaminar delamination, damage is described by cohesive model. A finite element model is established to analyze the damage process of composite laminate. A good agreement is got between damage predictions and experimental results.

Effect of preload and shim types on the mechanical properties of composite-aluminium bolted joints

2021 ◽  
pp. 095440622110071
Author(s):  
Xuande Yue ◽  
Luling An ◽  
Zengtao Chen ◽  
Yuebo Cai ◽  
Chufan Wang
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Damage Model ◽  
Peak Load ◽  
Lap Joints ◽  
Surface Strain ◽  
Displacement Curve ◽  
Progressive Damage ◽  
Single Lap Joints ◽  
Tensile Stiffness

The influence of both preload and the presence of shim types on the mechanical properties of composite-aluminium single-bolt, single-lap joints were studied in this paper. The load-displacement curve and surface strain field of joints in different shim types and preloads were obtained through tensile experiments. A progressive damage model was established using the UMAT subroutine in ABAQUS. A hybrid failure criterion and a linear continuous degradation model were used to describe the progressive damage of composite laminates. The results show that for joints with no shim and for those with various types of shims, the tensile stiffness, peak load and initial damage load could be reduced when the preload is insufficient or too large. Compared with joints with no shims or with peelable fibreglass shims, joints with liquid shims required a larger preload to achieve the best mechanical properties. As the proportion of peelable fibreglass shim increased, the tensile stiffness and peak load continued to increase in joints with a mixed shim of liquid and peelable fiberglass shim. Shims can serve as tension bearings, but have little effect on the initiation and development of bearing failure.

Progressive Damage Analysis of Random Chopped Fiber Composite Using Finite Elements

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Yi Pan ◽  
Assimina A. Pelegri
Keyword(s):  
Mechanical Properties ◽  
Cohesive Zone Model ◽  
Fiber Composite ◽  
Damage Model ◽  
Interfacial Debonding ◽  
Matrix Cracking ◽  
Uniaxial Tensile ◽  
Zone Model ◽  
Progressive Damage ◽  
Fiber Damage

The mechanical properties of random chopped fiber composites are analyzed using micromechanical principles. A progressive damage model is adopted to investigate the damage and failure of the material. A representative volume element is generated numerically based on microscopic observations that capture the complex mesostructure of the random chopped fiber composite specimens. Sequentially, the mechanical properties are obtained using a micromechanics approach, particularly, the homogenization method. The underlying hypothesis insinuates that damage mechanisms such as matrix cracking, fiber damage, and interfacial debonding are responsible for the damaged behavior of the composite. Matrix cracking and fiber damage are modeled by progressive degradation of their respective stiffnesses. The interfacial debonding is modeled with a cohesive zone model. The prediction of uniaxial tensile response is compared with experimental data.

Mechanical Properties Research of Carbon Fiber Composite Laminates

2020 ◽  
Vol 980 ◽  
pp. 107-116
Author(s):  
Hong Wang Zhao ◽  
Xiao Gang Liu ◽  
Abraham Kent
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Fiber Composite ◽  
Damage Model ◽  
Failure Criteria ◽  
Progressive Damage ◽  
Carbon Fiber Composite ◽  
Element Analysis ◽  
Cfrp Laminates ◽  
Progressive Damage Model

This paper expounds the basic theory of composite mechanics, and discusses the damage forms, damage analysis and failure criteria of composite materials. Then, the basic mechanical properties of unidirectional CFRP laminates with different layers, including modulus of elasticity, strength and so on, were obtained through a large number of experiments. Based on the experimental data, the relationship between the number of layers and the properties of materials was studied. The brittle fracture process of CFRP laminates was simulated by finite element analysis based on progressive damage model and compared with the force-displacement curves obtained by experiments. The validity of progressive damage model was proved.

Progressive damage characteristics of screwed single-lap CFRPI-metal joint subjected to tensile loading at RT and 350°C

2021 ◽  
pp. 002199832098559
Author(s):  
Yun-Tao Zhu ◽  
Jun-Jiang Xiong ◽  
Chu-Yang Luo ◽  
Yi-Sen Du
Keyword(s):  
Damage Model ◽  
Tensile Loading ◽  
Tensile Tests ◽  
Displacement Curve ◽  
Progressive Damage ◽  
Damage Characteristics ◽  
Metal Joint ◽  
Static Tensile ◽  
Strength And Stiffness ◽  
Progressive Damage Model

This paper outlines progressive damage characteristics of screwed single-lap CFRPI-metal joints subjected to tensile loading at RT (room temperature) and 350°C. Quasi-static tensile tests were performed on screwed single-lap CCF300/AC721-30CrMnSiA joint at RT and 350°C, and the load versus displacement curve, strength and stiffness of joint were gauged and discussed. With due consideration of thermal-mechanical interaction and complex failure mechanism, a modified progressive damage model (PDM) based on the mixed failure criterion was devised to simulate progressive damage characteristics of screwed single-lap CCF300/AC721-30CrMnSiA joint, and simulations correlate well with experiments. By using the PDM, the effects of geometry dimensions on mechanical characteristics of screwed single-lap CCF300/AC721-30CrMnSiA joint were analyzed and discussed.

scholarly journals Microstructure and Fracture Toughness of Fe–Nb Dissimilar Welded Joints

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 86
Author(s):  
Qiaoling Chu ◽  
Lin Zhang ◽  
Tuo Xia ◽  
Peng Cheng ◽  
Jianming Zheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Weld Metal ◽  
Thermal Cycle ◽  
Peak Load ◽  
Local Phase ◽  
Weld Formation ◽  
Lamellar Structures ◽  
Average Hardness ◽  
Radial Cracks

The relation between the microstructure and mechanical properties of the Fe–Nb dissimilar joint were investigated using nanoindentation. The weld metal consists mainly of Fe2Nb, α-Fe + Fe2Nb, Nb (s,s) and Fe7Nb6 phases. Radial cracks initiate from the corners of the impressions on the Fe2Nb phase (~20.5 GPa) when subjected to a peak load of 300 mN, whereas the fine lamellar structures (α-Fe + Fe2Nb) with an average hardness of 6.5 GPa are free from cracks. The calculated fracture toughness of the Fe2Nb intermetallics is 1.41 ± 0.53 MPam1/2. A simplified scenario of weld formation together with the thermal cycle is proposed to elaborate the way local phase determined the mechanical properties.

A progressive damage model for three-dimensional woven composites under ballistic impact loading

2019 ◽  
Vol 1 (1) ◽  
pp. 015028
Author(s):  
Yongqi Yang ◽  
Li Zhang ◽  
Licheng Guo ◽  
Suyang Zhong ◽  
Jiuzhou Zhao ◽  
...  
Keyword(s):  
Impact Loading ◽  
Damage Model ◽  
Three Dimensional ◽  
Ballistic Impact ◽  
Woven Composites ◽  
Progressive Damage ◽  
Progressive Damage Model

The Effects of Material Strength, Stress Ratio, and Compressive Overload on the Threshold Behavior of a SAE1045 Steel

1985 ◽  
Vol 107 (1) ◽  
pp. 19-25 ◽  
Author(s):  
M. T. Yu ◽  
T. H. Topper
Keyword(s):  
Mechanical Properties ◽  
Growth Rate ◽  
Threshold Stress ◽  
Stress Ratio ◽  
Peak Load ◽  
Load Level ◽  
Material Strength ◽  
Threshold Stress Intensity ◽  
Threshold Behavior ◽  
Rate Behavior

The fatigue crack growth rate behavior of a SAE1045 steel in the as received condition and four different quenched and tempered conditions was studied as a function of stress ratio and peak compressive overload. The threshold stress intensity behavior of the quenched and tempered conditions was not sensitive to changes of monotonic mechanical properties. The threshold decreased linearly with increasing positive stress ratio and compressive peak load level. As received ferritic-pearlitic SAE1045 steel was much more sensitive to stress ratio and compressive peak load than any of the quenched and tempered conditions studied.

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