scholarly journals Effect of Side Groove on Shear Lips Formation of Aluminium Alloy 6061 using Finite Element Analysis

Author(s):  
Mohd Azmeer Asry ◽  
◽  
Mohd Azhar Harimon ◽  

Aluminium alloys are commonly utilised to reduce the weight of vehicles as structural components due to their good mechanical properties, lightweight characteristics, ease of fabrication, and high specific strength. During an accident, aluminium alloys are subjected to high velocity and varying loads. As a result, it is crucial to understand the impact properties of aluminium alloys. The side groove influence on the shear lip development of the aluminium alloy Al6061 was investigated in this study. The Charpy impact test under different side groove depth ratio was conducted through simulation using Abaqus. It was found that the shear lips ratio decreased when the side groove depth ratio increased. The energy absorption and force required to fracture the specimen decreased when the side groove depth ratio increased. As a result of the lower shear lips ratio, less absorb energy, and less force of impact, increasing the side groove depth ratio will tend to lower Al6061 ductility.

Author(s):  
S. M. French

Two damaged final reheat tubes from a 30 year old supercritical unit were submitted to the laboratory for evaluation following the discovering of a failure of one of the tubes after deslagging operations; a third, dented tube was left in service. The 304H stainless steel tubes were installed in 1990 when the reheater was replaced. The bulk microstructure of both tubes shows evidence of sensitization, which is not unusual given this application (reheater). The failed tube appears to be an intergranular separation that started either subsurface or at the ID, propagating to the OD surface. The sensitization of the steel apparently made the material susceptible to corrosion as well as significantly reduced the impact strength of the material to 10–15% of its estimated original level (verified by Charpy impact test). Examination of the dented tube (#101A) showed a subsurface plane of damage some 30 mils from the ID surface, running parallel to the surface. The damage consisted of intergranular separation, caused by the impact loading event, and referred to in the literature as an “attached spalling failure”. Spalling failures occur when the shock wave is reflected from the back surface (the ID surface of the tube), interacting with the incident shock wave as a stress wave. When the magnitude of this tensile stress exceeds the inherent strength of the material, failure occurs. The overall area of the attached spalling failure is being investigated; the concern there is if it is exceptionally large, it may provide a thermal barrier to heat transfer from the OD to the ID and result in a local overheating failure. Within the metallographic sample, however, the damage area was quite small and therefore did not appear to be an immediate issue. The long-term suitability of tube 105A, which remains in service with a dent induced by the same deslagging process that damaged tubes 101A and 103A, is doubtful and should be addressed during the Fall 2006 boiler overhaul. For the shortterm, the assumption was made that cracking due to the deslagging impact would be oriented similar to non-failed tube and extension of these fissures to failure between Spring 2006 and the Fall outage is not expected.


2009 ◽  
Vol 23 (06n07) ◽  
pp. 1885-1890 ◽  
Author(s):  
ZUOCHENG WANG ◽  
GUOTAO CUI ◽  
TAO SUN ◽  
WEIMIN GUO ◽  
XIULING ZHAO ◽  
...  

In our research, boron was added into the Nb -added high strength low alloy (HSLA) H -section steels. The contents of boron added were 4ppm, 8ppm and 11ppm, respectively. The mechanical properties of H -section steels with/without boron were examined by using uniaxial tensile test and Charpy impact test ( V -notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results indicate that boron gives a significant increase in impact toughness, especially in low temperature impact toughness, though it leads to an unremarkable increase in strength and plasticity. For instance, the absorbed energy at -40°C reaches up to 126J from 15J by 8ppm boron addition, and the ductile-brittle transition temperature declines by 20°C. It is shown that boron has a beneficial effect on grain refinement. The fracture mechanism is transited from cleavage fracture to dimple fracture due to boron addition.


2014 ◽  
Vol 775-776 ◽  
pp. 296-301 ◽  
Author(s):  
Anderson de Paula Barbosa ◽  
Michel Picanço Oliveira ◽  
Giulio Rodrigues Altoé ◽  
Frederico Muylaert Margem ◽  
Sergio Neves Monteiro

The buriti (Muritia flexuosa) fiber are among the lignocellulosic fibers with apotential to be used as reinforcement of polymer composites. In recent years, the buriti fiber has been characterized for its properties as an engineering natural material. The toughness of buriti composites remains to be a evaluated. Therefore, the present work evaluated the toughness of epoxy composites reinforced with different amounts of buriti fibers by means of Charpy impact tests. It was found a significant increase in the impact resistance with the volume fraction of buriti fibers. Fracture observations by scanning electron microscopy revealed the mechanism responsible for this toughness behavior.


2012 ◽  
Vol 602-604 ◽  
pp. 2096-2099
Author(s):  
Min You ◽  
Ling Wu ◽  
Hai Zhou Yu ◽  
Jing Rong Hu ◽  
Mei Li

The effect of the shock temperature and time on the impact toughness of the adhesively bonded steel butt joint under Charpy or Izod impact test is studied using the experimental method. The results obtained show that the impact toughness decreases when the shock temperature increased. When the curing time, temperature as well as the open assembly time was set as constant, the higher the shock temperature is, the lower the impact toughness of the joint. Comparing to the Charpy impact test, the Izod impact test is more sensitive to the shock temperature. When the shock temperature is set at a value not less than 300 C, the impact toughness measured is nearly the same as zero due to decomposition, carbonization and volatilization of the adhesive.


2020 ◽  
pp. 002199832092314
Author(s):  
Adefemi Adeodu ◽  
Lateef Mudashiru ◽  
Ilesanmi Daniyan ◽  
Abdulmalik Awodoyin

Mechanical properties (impact, hardness and tensile strength) characterization of samples containing homogenous mixtures of Al 6063 matrix and varying amount of silver nanoparticles mixed with calcium carbonate at 2, 4, 6% weight fractions, respectively, produced by method of stir casting were carried out. Measurement of impact energy, hardness and tensile strength of the produced samples at 24℃ (ambient) temperature was done by Charpy impact, Brinell hardness and universal tensile testing machine in accordance to ASTM E23, E384 and E8/E8M-13M, respectively. The magnitude of impact and hardness increased evidently with increase in percentage weight fraction of the AgNPs. The refined samples were examined under an optical microscope. The fracture surfaces of the impact test samples were further examined by scanning electron microscopy. There is an increase in tensile strength, elongation and modulus of elasticity of Al-AgNP composites compared to as-cast aluminium alloy. The use of stir-casting technique influences the homogeneity and microstructure of the composites positively. It is concluded that Al-silver nanocomposites possess better qualities in hardness and strength and can replace conventional aluminium alloy in terms of performance and longer life in industrial application.


2020 ◽  
Vol 867 ◽  
pp. 98-102
Author(s):  
H.C. Kis Agustin ◽  
Indra Sidharta ◽  
Leonard

Stirring is one the most utilized process in small foundry. It is used for homogenizing the temperature and mixing process during melting. However, stirring may cause undesirable effect to the quality of castings if it is not managed properly. Bifilm is one of the defects that can be detrimental to the quality of aluminium castings, and its formation can be related to the stirring during melting. The research aim is to investigate the effect of stirring during melting of cast aluminium alloys. The quality of castings is approached by the term of bifilm index and mechanical properties. ADC 12 cast aluminium alloys is used in the experiment. The ADC 12 ingots are melted at 720 °C, and then stirred for 0, 3 and 5 minutes. Reduced Pressure Test is used for determining the bifilm index. Samples for mechanical testing are also casted into specific geometry. Results indicate that prolonged stirring time increases the bifilm index, indicating that more porosity and bifilm oxide are formed. Extended stirring time instigates more turbulence in liquid metal, hence surface oxides are folded and trapped in the bulk liquid metal. Charpy impact test, hardness test and tensile test have also carried out. More Porosity and bifilm oxide are formed in the samples and tend to decrease the mechanical property.


2020 ◽  
Vol 12 (2) ◽  
pp. 168781402090456
Author(s):  
Guojun Wei ◽  
Chenglong Wang ◽  
Xingwang Yang ◽  
Zhenfeng Tong ◽  
Wenwang Wu

The mechanical performance of reactor pressure vessel materials is an important factor in the safety and economics of the operation of a nuclear power plant. The ductile-to-brittle transition temperature tested by Charpy impact test is the key parameter for evaluating the reactor pressure vessel embrittlement. In this article, the study of thermal aging embrittlement of temperature sets of reactor pressure vessel surveillance Ni-Cr-Mo-V steel weld metal was conducted by Charpy impact test. The thermal aging effect on the impact fracture behavior was analyzed. The impact test of the three batches of weld surveillance sample indicated that the weld metal embrittled during thermal aging. The study of impact fracture and Auger electron spectroscopy indicated that the element P segregated to the grain boundaries and lowered their cohesion strength during the long-term thermal aging. Therefore, the non-hardening embrittlement of Ni-Cr-Mo-V steel welds in a reactor pressure vessel caused by segregation of impurity elements P occurs during thermal aging.


Author(s):  
T. Vinodkumar ◽  
M. Chandrasekaran ◽  
P. Vivek ◽  
S. Arunkumar ◽  
S. Padmanabhan

This study motivates the state of relying on the non-degradable plastic packaging to develop the alternative material namely reinforced poly lactic acid (PLA) with snake grass fibre (SG) and sisal fibre (SF) bio composite. Injection moulding fabrication method is used. For mechanical characterization, SG/SF is loaded with an effect from 10 to 30 wt.%. Similarly, the tensile and flexural properties are significant to improve the attained wt. % of SG/SF. Additionally, PLA-SG/SF bio composite produced is having high specific strength and specific modulus. The suggested one in SG/SF may be integrated into PLA to reduce the mass of the end product and substantially reduce the cost of raw materials. The impact strength tends to decrease with SG/SF content. Finite element analysis was carried out to correlate the experimental values.


2018 ◽  
Vol 32 (6) ◽  
pp. 729-745 ◽  
Author(s):  
Olivier De Almeida ◽  
Jean-François Ferrero ◽  
Laurent Escalé ◽  
Gérard Bernhart

The aim of the work is to use Charpy impact test for quick evaluations of different Polyether-ether-ketone (PEEK)-reinforced composites to be used for impact protection. In the first part, the influence of weave pattern was first analysed by comparing the impact behaviour of three PEEK composites reinforced with plies of unidirectional (UD) tapes, 5H satin fabrics and 2 × 2 twill fabrics made of high-strength carbon fibres. In the second part, the influence of fibre nature was investigated for the same weave pattern. The impact behaviour of five 2 × 2 twill fabrics made from inorganic fibre (carbon, glass and basalt) and organic fibre (aramid and poly(p-phenylene-2,6-benzobisoxazole) (PBO)) has been compared. Two main types of failure modes were identified: a brittle behaviour mode with high failure strength and a highly deformable behaviour mode in which energy absorption is more important. The balance between brittle behaviour and highly deformable behaviour results from competition between the yarn crimp, weave pattern and fibre properties of the composite. Slight yarn crimp and small ply thickness increase the stiffness of the composite and induce brittle behaviour characterized by fibre failure in tension and a steep peak on the loading curves. This behaviour is observed in UD and 5H satin carbon-reinforced composites or 2 × 2 twill glass and basalt fabric-reinforced composites. In contrast, aramid and PBO 2 × 2 twill fabric composites exhibit high shear strength. The highly deformable behaviour of the specimens during the Charpy impact led, in the case of organic fibres, to a non-breakage of the fibres and consequently to a high level of energy absorption. This behaviour is necessarily interesting in armour applications.


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