Fatigue properties of parts printed by PolyJet material jetting

2015 ◽  
Vol 21 (6) ◽  
pp. 675-685 ◽  
Author(s):  
Jacob P. Moore ◽  
Christopher B. Williams
Keyword(s):  
Fatigue Life ◽  
Optical Microscope ◽  
Design Guidelines ◽  
Test Method ◽  
Fatigue Properties ◽  
Repeated Loading ◽  
Material Interface ◽  
Content Type ◽  
End Use ◽  
The Relationship

Purpose – This paper aims to seek to fill a gap in the literature by characterizing the fatigue life and microstructure of a printed elastomer material, the TangoBlackPlus material. Design/methodology/approach – Because the TangoBlackPlus material is marketed as “rubber-like”, the printed elastomer specimens were tested according to the ASTM D4482-11 “Test Method for Rubber Property Extension Cycling Fatigue”. The microstructure of the printed material and multi-material interface was examined by slicing specimens and examining them under an optical microscope. Findings – Findings are developed to show the relationship between elongation and expected fatigue life. Findings also indicate that the smoother, non-support encased “glossy” surface finish option for PolyJet parts improve the fatigue life of components and that there are a number of microscopic voids in the TangoBlackPlus material that seem to be concentrated at layer and print head boundaries. Research limitations/implications – This paper provides a glimpse into the fatigue properties and microstructure of printed elastomeric parts, a previously unstudied area. This work is limited in that it only looks at specimens created in a single orientation, on a single machine, with a single material. More work is needed to understand the general fatigue properties of printed elastomers and the factors that influence fatigue life in these materials. Practical implications – The authors provide several design guidelines based on the findings and previous work that can be used to increase the fatigue life of printed elastomer components. Originality/value – As additive manufacturing (AM) technology moves from a prototyping tool to a tool used to create end use products, it is important to examine the expected lifespan of AM components. This work adds to the understanding of the expected product lifecycle of printed elastomer components that will likely be expected to withstand large repeated loading conditions.

scholarly journals Effect of Carburizing and Nitriding on Fatigue Properties of 18Cr2Ni4WA Steel in Very High Cycle Fatigue Regime

2021 ◽  
Vol 45 (3) ◽  
pp. 207-215
Author(s):  
Zhenduo Sun ◽  
Dongbo Hou ◽  
Wei Li
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Internal Defect ◽  
Surface Fatigue ◽  
Very High Cycle Fatigue ◽  
The Relationship ◽  
Very High

The work aims to study the influence of carburizing and nitriding on fatigue properties of 18Cr2Ni4WA high strength steel in very high cycle fatigue regime. Very high cycle fatigue tests were carried out on 18Cr2Ni4WA Steel after carburizing and nitriding respectively. The micro morphology of fatigue fracture was observed by scanning electron microscope, the failure mode and failure mechanism were discussed. The relationship between fatigue life and defect size, FGA size, fish eye size of fracture was analyzed. The characteristic size of defects is evaluated by Gumbel, Weibull and GEV distribution functions, and a modified Akiniwa fatigue life prediction model considering the relationship between FGA size and inclusion size was established. The results showed that, nitriding and carburizing treatment improve the surface fatigue limit of the steel. The fatigue life decreases with the increase of internal defect size and FGA size. After carburizing and nitriding treatment, the internal fatigue strength of the specimen decreases slightly. When the failure probability is 99%, the internal defect sizes of nitrided specimens calculated by Weibull, Gumbel and GEV distributions are 141.5 μm, 148.4 μm and 211.7 μm respectively. The calculated internal defect sizes of carburized specimens are 47 μm, 67.8 μm and 40 μm respectively. Compared with the experimental data, the fatigue strength predicted by GEV is the most appropriate. carburizing and nitriding treatment can improve the surface fatigue strength of 18Cr2Ni4WA steel, but slightly reduce the internal fatigue strength. The prediction result of the new model is conservative when the failure probability is 99%, which is suitable for engineering application.

scholarly journals Experimental Study on the Reliability of PBGA Electronic Packaging under Shock Loading

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 279 ◽  
Author(s):  
Jiang Shao ◽  
Hongjian Zhang ◽  
Bo Chen
Keyword(s):  
Fatigue Life ◽  
Electronic Packaging ◽  
Failure Modes ◽  
Solder Joints ◽  
Optical Microscope ◽  
Micro Cracks ◽  
Plastic Ball ◽  
Plastic Ball Grid Array ◽  
Aeronautical Industry ◽  
The Relationship

Plastic Ball Grid Array (PBGA) one of the most important electronic packaging methods, is widely used in aeronautical industry field. According to the JEDEC standard, shock tests of PBGA assemblies are conducted under different loading conditions. Several important parameters, such as the fatigue life of PBGA assemblies, the relationship between solder joint positions and fatigue life, the relationship between strain energy density and fatigue life, are analyzed based on experiment results. The failure modes of PBGA assemblies are studied by optical microscope (OM). The results show that during the shock tests, the strains of the solder joints near the center of the specimen are larger than other positions, and these solder joints are prone to form micro cracks. With the increase of the shock times, these micro cracks extend rapidly which will eventually cause the failure of the PBGA electronic packaging.

Cut Growth and Fatigue of Rubbers. I. The Relationship between Cut Growth and Fatigue

1965 ◽  
Vol 38 (2) ◽  
pp. 292-300 ◽  
Author(s):  
A. N. Gent ◽  
P. B. Lindley ◽  
A. G. Thomas
Keyword(s):  
Fatigue Life ◽  
Repeated Loading ◽  
Simple Extension ◽  
Test Pieces ◽  
Energy Concept ◽  
Tearing Energy ◽  
Mechanism Of Failure ◽  
Natural Rubber Vulcanizates ◽  
The Relationship ◽  
Good Agreement

Abstract The relationship between the cut growth and fatigue failure of natural rubber vulcanizates under repeated loading is examined. The cut growth behavior has been investigated using several types of test piece, and the results are shown to be consistent when interpreted in terms of the tearing energy concept developed previously. The most comprehensive data have been obtained by measuring the growth of a small cut in the edge of a strip cycled in simple extension. It is found that the cut growth per cycle is approximately proportional to the square of the maximum tearing energy attained during the cycle. Using this relation, the fatigue life of a specimen containing a small cut is deduced from elasticity theory as a function of initial cut size and maximum strain. Experimental results give good agreement with theory. A similar strain dependence is found for the fatigue life of die-stamped dumbbell test pieces with no intentionally produced flaws; this is consistent with the mechanism of failure being cut growth from small flaws present in the specimens. Their effective size is estimated to be about 2×10−3 cm, which is compatible with the observed superficial imperfections of the cut edges.

Fatigue and Fretting Fatigue Behavior of Metallic Biomaterials

2010 ◽  
Vol 638-642 ◽  
pp. 618-623
Author(s):  
Norio Maruyama
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Fatigue Behavior ◽  
Fretting Fatigue ◽  
Test Method ◽  
Fatigue Properties ◽  
Metallic Biomaterials ◽  
The Relationship

A fretting fatigue test method in a simulated body fluid is shown to evaluate fatigue properties of metallic materials which are used in the orthopaedics field. Next, fatigue/fretting fatigue behavior in a simulated body fluid is given for 316L stainless steel, Ti-6% Al-4% V alloy, pure Ti for industrial use and Co-Cr-Mo alloy. Finally, we discuss the relationship between the tensile strength and the fatigue strength/fretting fatigue strength of metallic biomaterials at 107 cycles in air and in a simulated body fluid. For all of the biomaterials tested, the fatigue strength at 107 cycles is similar in air and in a simulated body fluid. The fatigue strength is closely correlated to the tensile strength: The fatigue strength increases with increasing tensile strength. However, a correlation is not observed between the fretting fatigue strength at 107 cycles and the fatigue strength or the tensile strength.

Reliability Evaluation of Fatigue Life for Solder Joints in Chip Components Considering Dispersion of the Shape and the Properties

2011 ◽  
Author(s):  
Yuji Nishimura ◽  
Qiang Yu
Keyword(s):  
Fatigue Life ◽  
Material Properties ◽  
Solder Joints ◽  
Test Method ◽  
Fatigue Properties ◽  
Simulation Approach ◽  
Fiber Network ◽  
Heterogeneous Model ◽  
Isothermal Fatigue ◽  
Simulation Results

Recently, the downsizing of car components becomes a big trend for the development of car electronics, and it is becoming very difficult to achieve the reliability results target without managing controlling the dispersion of the fatigue lives. The authors proposed an isothermal fatigue test method using small size solder joints to get the fatigue properties. The Manson-Coffin’s law given by this method could improve the correspondence between the simulation results and experimental results. Based upon the Manson-Coffin’s law and Miner’s law, the authors proposed a fatigue crack propagation simulation approach. Furthermore, in order to consider the heterogeneity of PCB due to the distribution of fiber network, the authors made heterogeneous model considering the distribution of the fiber. And the authors evaluated the fatigue life of solder joints in chip components with considering dispersion of the material properties by using the heterogeneous model.

Specimen Size Effect on Fatigue Properties of Surface-Micromachined Al-3%Ti Thin Films

2007 ◽  
Author(s):  
Jun-Hyub Park ◽  
Man Sik Myung ◽  
Yun-Jae Kim
Keyword(s):  
Thin Film ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Evaluation Method ◽  
High Cycle Fatigue ◽  
Test Procedure ◽  
Fatigue Tests ◽  
Test Method ◽  
Fatigue Properties ◽  
Cycle Fatigue

This paper presents high cycle fatigue properties of an Al-3%Ti thin film, used in a RF (radio-frequency) MEMS switch for a mobile phone and also describes new test method for obtaining static and dynamic characteristics of thin film and reliability evaluation method on MEMS device with thin film developed by authors. Durability should be ensured for such devices under cycling load. Therefore, with the proposed specimen and test procedure, tensile and fatigue tests were performed to obtain mechanical and fatigue properties. The specimen was made with dimensions of 1000μm long, 1.0μm thickness, and 3 kinds of width, 50, 100 and 150μm. High cycle fatigue tests for each width were also performed, from which the fatigue strength coefficient and the fatigue strength exponent were found to be 193MPa and −0.02319 for 50μm, 181MPa and −0.02001 for 100μm, and 164MPa and −0.01322 for 150μm, respectively. We found that the narrower specimen is, the longer fatigue life of Al-3%Ti is and the wider specimen is, the more susceptible to stress level fatigue life of Al-3%Ti was.

Study on Fatigue Properties of Copper Alloy Netting Structure

2019 ◽  
Vol 814 ◽  
pp. 275-282
Author(s):  
Shao Min Wang ◽  
Yu Qiu ◽  
Jie Jin Guo ◽  
Tai Ping Yuan ◽  
Hai Yang Liu
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Ultimate Strength ◽  
Copper Alloy ◽  
Failure Modes ◽  
Copper Wire ◽  
Great Influence ◽  
Fatigue Tests ◽  
Test Method ◽  
Fatigue Properties

Aiming at the damage and failure problem of copper alloy netting structure, the ultimate strength and fatigue performance of the net structure were studied by test method. Based on the research on the ultimate strength of copper wire, through a series of fatigue tests on copper wire and net structure, the fatigue life and failure modes of copper wire and net structure under different loads are analyzed, and their fatigue life curves are also drawn. The results show that the fatigue strength of copper wire and net structure considering corner processing is lower than that of copper wire not considering corner processing, which indicates that corner processing has a great influence on the fatigue strength of actual copper net structure. Compared with the fatigue strength value of 32.8 MPa of the copper net, the fatigue strength value of the net structure decreases to a certain extent (about 14.3%), which indicates that the assembly process of the copper net has certain influence on the fatigue life of the net structure.

Comparative fatigue properties estimation of composite structural nodes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Miroslaw Rodzewicz
Keyword(s):  
Fatigue Life ◽  
Composite Structures ◽  
Evaluation Process ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Composite Shells ◽  
Concentrated Force ◽  
Content Type ◽  
Structural Discontinuity ◽  
Strength Difference

Purpose The purpose of this paper is to present the concept of the author’s method of fatigue properties assessment of polymer composite structures, especially structures having nodes of concentrated force introduction (NCFI) using fatigue test data of coupons of similar composites and the ratio of their structural stress rate factors. Design/methodology/approach Basing on fatigue properties of pure composite shells coupons subjected to cyclic loads, and basing on the static strength difference between pure composite shells and shells having the structure affected by NCFI – (considered here as not only a manner of load introduction but also a kind of structural discontinuity), a method of relative fatigue properties reduction (RFPR) was developed. In the RFPR evaluation process, the author used the results of experiments on a special type of an NCFI named “a labyrinth non-adhesive node of concentrated force introduction” (LNA-NCFI) applied in certain composite gliders for fitting glider wings with the fuselage and also referred to design directives relating to primary structure of composite gliders, which are presented in the form of lightness factors linking stress with a structural mass. Findings The result of RFPR method application matched well with the results of fatigue tests of the LNA-NCFI type of a NCFI. The RFPR method may significantly facilitate the estimation of fatigue life of a structure with a structural discontinuity or an NCFI. Practical implications The RFPR method may significantly facilitate the estimation of fatigue life of a structure with a structural discontinuity or an NCFI. Originality/value The paper presents a proposal of a novel simplified method for fatigue life estimation of composite structures having a kind of structural discontinuity or an NCFI.

scholarly journals Strength and Fatigue Properties of Sandstone under Dynamic Cyclic Loading

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Mingming He ◽  
Ning Li ◽  
Yunsheng Chen ◽  
Caihui Zhu
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Mechanical Characteristics ◽  
Stress Amplitude ◽  
Dynamic Strength ◽  
Fatigue Properties ◽  
Loading Frequency ◽  
Strength And Deformation ◽  
Metal Materials ◽  
The Relationship

This paper presents an experimental investigation of strength and fatigue properties of intact sandstone samples subjected to dynamic cyclic loading in the laboratory. Tests were conducted on sandstone samples with loading frequencies ranging in 0.5, 1, 2, and 4 Hz, loading amplitudes of 1, 15, 30, 60, 90, and 120 kN, and loading speeds of 0.5, 1, 2, 4, and 8 kN/s. In this study it was shown that the loading frequency, as well as the amplitude and loading speed, was of great significance and affected the mechanical characteristics of sandstone under dynamic cyclic loading. The fatigue life of sandstone was found to decrease with loading speeds and amplitudes but increase with loading frequencies. It was found that the minimum of the dynamic strength and deformation factor of sandstone was obtained at loading speeds of 2 kN/s but the maximum at loading frequencies of 1 Hz. Finally, it was concluded that the relationship between the fatigue life and loading speed, frequency, and stress amplitude under dynamic cyclic loading would be expressed as theS-Ncurve, which showed that the fatigue characteristic of sandstone was similar to that of metal materials.

scholarly journals Effects of Pore Size on Fatigue Deformation Mechanism of Open-Cell Copper Foam at Low Stress Amplitude

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1639 ◽  
Author(s):  
Jian Chen ◽  
Shuowei Dai ◽  
Cong Li ◽  
Wei Li ◽  
Yanjie Ren
Keyword(s):  
Fatigue Life ◽  
Pore Size ◽  
Strain Amplitude ◽  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Optical Microscope ◽  
Fatigue Properties ◽  
Exponential Relationship ◽  
Open Cell ◽  
Copper Foam

Axial compression-compression fatigue experiments on open-cell copper foams with different pore size were investigated in this paper. The effects of the strain amplitude on the fatigue properties were studied and found that there is an exponential relationship between the fatigue life and strain amplitude. The experimental results indicate that a smaller pore size is related to a lower fatigue life. The microstructures of failed copper foam tested at low stress amplitude were observed by optical microscope and scanning electron microscopy (SEM), suggests that different pore size related to different fatigue behavior. The fatigue failure mechanism of the open-cell copper foams were compared by experimental research.

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