Statistical characteristic of the impact strength of hardened glass

Практика показывает, что для сварных конструкций, эксплуатируемых в условиях Крайнего Севера необходимо уделять внимание работоспособности сварных соединений при низких температурах. Металл сварных соединений в процессе воздействия обработки изменяет свои свойства, снижается ударная вязкость, образуется гетерогенная структура с большой степенью разнозернистости. Чтобы оценивать и иметь возможность правильно контролировать термическое воздействие и последствия сварочного процесса, требуется решить задачу аналитического определения ударной вязкости для всех зон сварного соединения. В настоящей статье представлен инженерный метод оценки ударной вязкости, применимый для любой зоны сварного соединения, в которой имеется острый или особый концентратор напряжений – трещина. Разработанный аналитический метод расчета ударной вязкости отражает качественную и количественную картину взаимосвязи структурно-механических характеристик и работы развития трещины в диапазоне температур 77…300 К. Предложенная схематизация зависимости критического коэффициента интенсивности напряжений от температуры позволила найти коэффициенты, характеризующие свойства материала, и выполнить расчеты изменения предела текучести и предела прочности от температуры эксплуатации. Построены графики зависимости работы развития трещины от температуры эксплуатации для сталей 15ГС и 17ГС, сравнение которых с экспериментальными данными показывает удовлетворительное согласование. Найдено, что при напряжениях предела выносливости отношение работы развития трещины к критической длине трещины постоянно, не зависит от температуры и для сталей 15ГС и 17ГС равно около 10. Ключевые слова: ударная вязкость, работа разрушения, коэффициент интенсивности напряжений, трещина, феррито-перлитная сталь, зона термического влияния. For welded structures under operation in the Far North, attention must be paid to the performance of welded joints at low temperatures. The properties of metal of welded joints are changed in the process of treatment, its toughness decreases, and a heterogeneous structure with a large range of different grain sizes is formed. In order to evaluate and be able to correctly control the thermal effect and the consequences of the welding process, it is necessary to solve the problem of analytical determination of impact strength for all zones of the welded joint. The paper presents an engineering method for evaluation of the impact strength applicable to any area of the welded joint in which there is a sharp or super sharp stress concentrator – a crack. The developed analytical method for calculating the impact strength reflects a qualitative and quantitative codependency of structural and mechanical characteristics and the process of crack development in the temperature range of 77–300 K. The proposed schematization of dependence of the critical coefficient of stress intensity on the temperature made it possible to find coefficients characterizing the properties of the material and to perform calculations of changes in yield strength and tensile strength on operating temperature. Graphs of the crack development process dependency on the operating temperature for 15ГС and 17ГС steels were constructed, and their comparison with experimental data displays satisfactory agreement. It was found that at endurance limit stresses, the ratio of the crack development process to the critical crack length is constant, non-dependent on temperature, and is equal to 10 for 15ГС and 17ГС steels. Keywords: impact strength, fracture work, stress intensity factor, crack, ferrite-pearlite steel, heat affected zone, steel tempering.

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Impact Strength, Flexural Modulus and Wear Rate of PMMA Composites Reinforced by Eggshell Powders

Engineering and Technology Journal ◽

10.30684/etj.v38i7a.384 ◽

2020 ◽

Vol 38 (7A) ◽

pp. 960-966

Author(s):

Aseel M. Abdullah ◽

Hussein Jaber ◽

Hanaa A. Al-Kaisy

Keyword(s):

Impact Strength ◽

Wear Rate ◽

Flexural Modulus ◽

Matrix Material ◽

Weight Fraction ◽

Pure Pmma ◽

Calcination Process ◽

The Matrix ◽

The Impact ◽

Interface Bond

In the present study, the impact strength, flexural modulus, and wear rate of poly methyl methacrylate (PMMA) with eggshell powder (ESP) composites have been investigated. The PMMA used as a matrix material reinforced with ESP at two different states (including untreated eggshell powder (UTESP) and treated eggshell powder (TESP)). Both UTESP and TESP were mixed with PMMA at different weight fractions ranged from (1-5) wt.%. The results revealed that the mechanical properties of the PMMA/ESP composites were enhanced steadily with increasing eggshell contents. The samples with 5 wt.% of UTESP and TESP additions give the maximum values of impact strength, about twice the value of the pure PMMA sample. The calcination process of eggshells powders gives better properties of the PMMA samples compared with the UTESP at the same weight fraction due to improvements in the interface bond between the matrix and particles. The wear characteristics of the PMMA composites decrease by about 57% with increases the weight fraction of TESP up to 5 wt.%. The flexural modulus values are slightly enhanced by increasing of the ESP contents in the PMMA composites.

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Evaluation of the Aging Behavior of High Density Polyethylene in Thermal Oxidative Environment by Principal Component Analysis

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.727.447 ◽

2017 ◽

Vol 727 ◽

pp. 447-449 ◽

Cited By ~ 1

Author(s):

Jun Dai ◽

Hua Yan ◽

Jian Jian Yang ◽

Jun Jun Guo

Keyword(s):

Principal Component Analysis ◽

Impact Strength ◽

High Density Polyethylene ◽

Tensile Modulus ◽

Principal Component ◽

Component Analysis ◽

High Density ◽

Aging Behavior ◽

Data Set ◽

The Impact

To evaluate the aging behavior of high density polyethylene (HDPE) under an artificial accelerated environment, principal component analysis (PCA) was used to establish a non-dimensional expression Z from a data set of multiple degradation parameters of HDPE. In this study, HDPE samples were exposed to the accelerated thermal oxidative environment for different time intervals up to 64 days. The results showed that the combined evaluating parameter Z was characterized by three-stage changes. The combined evaluating parameter Z increased quickly in the first 16 days of exposure and then leveled off. After 40 days, it began to increase again. Among the 10 degradation parameters, branching degree, carbonyl index and hydroxyl index are strongly associated. The tensile modulus is highly correlated with the impact strength. The tensile strength, tensile modulus and impact strength are negatively correlated with the crystallinity.

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X-ray Shielding, Mechanical, Physical, and Water Absorption Properties of Wood/PVC Composites Containing Bismuth Oxide

Polymers ◽

10.3390/polym13132212 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2212

Author(s):

Worawat Poltabtim ◽

Ekachai Wimolmala ◽

Teerasak Markpin ◽

Narongrit Sombatsompop ◽

Vichai Rosarpitak ◽

...

Keyword(s):

Impact Strength ◽

Water Absorption ◽

Attenuation Coefficient ◽

Bismuth Oxide ◽

Morphological Properties ◽

Linear Attenuation Coefficient ◽

X Rays ◽

Equivalent Thickness ◽

X Ray ◽

The Impact

The potential utilization of wood/polyvinyl chloride (WPVC) composites containing an X-ray protective filler, namely bismuth oxide (Bi2O3) particles, was investigated as novel, safe, and environmentally friendly X-ray shielding materials. The wood and Bi2O3 contents used in this work varied from 20 to 40 parts per hundred parts of PVC by weight (pph) and from 0 to 25, 50, 75, and 100 pph, respectively. The study considered X-ray shielding, mechanical, density, water absorption, and morphological properties. The results showed that the overall X-ray shielding parameters, namely the linear attenuation coefficient (µ), mass attenuation coefficient (µm), and lead equivalent thickness (Pbeq), of the WPVC composites increased with increasing Bi2O3 contents but slightly decreased at higher wood contents (40 pph). Furthermore, comparative Pbeq values between the wood/PVC composites and similar commercial X-ray shielding boards indicated that the recommended Bi2O3 contents for the 20 pph (40 ph) wood/PVC composites were 35, 85, and 40 pph (40, 100, and 45 pph) for the attenuation of 60, 100, and 150-kV X-rays, respectively. In addition, the increased Bi2O3 contents in the WPVC composites enhanced the Izod impact strength, hardness (Shore D), and density, but reduced water absorption. On the other hand, the increased wood contents increased the impact strength, hardness (Shore D), and water absorption but lowered the density of the composites. The overall results suggested that the developed WPVC composites had great potential to be used as effective X-ray shielding materials with Bi2O3 acting as a suitable X-ray protective filler.

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Experimental and Numerical Measurement of the Impact Strength of Poly-lactic Acid through a Low-velocity Impact

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1094/1/012171 ◽

2021 ◽

Vol 1094 (1) ◽

pp. 012171

Author(s):

Ali Jasim Mohammed Al-Behadili ◽

Bashar Owaid Bedaiwi

Keyword(s):

Lactic Acid ◽

Impact Strength ◽

Low Velocity Impact ◽

Poly Lactic Acid ◽

Low Velocity ◽

Velocity Impact ◽

The Impact

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A comparative experimental study on the impact strength of standard and asymmetric involute spur gears

Measurement ◽

10.1016/j.measurement.2020.108950 ◽

2021 ◽

Vol 172 ◽

pp. 108950

Author(s):

Onur Can Kalay ◽

Oğuz Doğan ◽

Tufan Gürkan Yılmaz ◽

Celalettin Yüce ◽

Fatih Karpat

Keyword(s):

Experimental Study ◽

Impact Strength ◽

Spur Gears ◽

The Impact

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A novel recycled polyethylene terephthalate/polyamide 11 (rPET/PA11) thermoplastic blend

Progress in Rubber Plastics and Recycling Technology ◽

10.1177/14777606211001074 ◽

2021 ◽

pp. 147776062110010

Author(s):

Zahid Iqbal Khan ◽

Zurina Binti Mohamad ◽

Abdul Razak Bin Rahmat ◽

Unsia Habib ◽

Nur Amira Sahirah Binti Abdullah

Keyword(s):

Mechanical Properties ◽

Impact Strength ◽

Flexural Strength ◽

Polyethylene Terephthalate ◽

Practical Implication ◽

Polyamide 11 ◽

Recycled Polyethylene ◽

Twin Screw ◽

Electron Microscopy Analysis ◽

The Impact

This work explores a novel blend of recycled polyethylene terephthalate/polyamide 11 (rPET/PA11). The blend of rPET/PA11 was introduced to enhance the mechanical properties of rPET at various ratios. The work’s main advantage was to utilize rPET in thermoplastic form for various applications. Three different ratios, i.e. 10, 20 and 30 wt.% of PA11 blend samples, were prepared using a twin-screw extruder and injection moulding machine. The mechanical properties were examined in terms of tensile, flexural and impact strength. The tensile strength of rPET was improved more than 50%, while the increase in tensile strain was observed 42.5% with the addition of 20 wt.% of PA11. The improved properties of the blend were also confirmed by the flexural strength of the blends. The flexural strength was increased from 27.9 MPa to 48 MPa with the addition of 30 wt.% PA11. The flexural strain of rPET was found to be 1.1%. However, with the addition of 10, 20 and 30 wt.% of PA11, the flexural strain was noticed as 1.7, 2.1, and 3.9% respectively. The impact strength of rPET/PA11 at 20 wt.% PA11 was upsurged from 110.53 to 147.12 J/m. Scanning electron microscopy analysis revealed a dispersed PA11 domain in a continuous rPET matrix morphology of the blends. This work practical implication would lead to utilization of rPET in automobile, packaging, and various industries.

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