Research Article
Validity of Laws for Predicting Lifespan of Welded Points Under Variable Loading
Issue:
Volume 12, Issue 4, December 2024
Pages:
80-93
Received:
25 September 2024
Accepted:
15 October 2024
Published:
11 November 2024
DOI:
10.11648/j.ajee.20241204.11
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Abstract: The article examines the validity of the laws for predicting the life of welded points under variable amplitude loading, using three steels (HE360D, XE360D and XES) supplied by ArcelorMittal to Renault for the manufacture of automobile chassis parts. The fatigue tests revealed two modes of failure: cracking of the sheets at medium stresses and shearing of the molten core at high forces. For lifespan prediction, three damage laws were studied: Miner's law, Mesmacque and Amrouche law, and a proposed model. Miner's law, despite its simplicity and wide distribution, shows notable limitations in the presence of variable loads, because it does not take into account the interactions between successive load levels. The law of Mesmacque and Amrouche uses a damage indicator linked to the FN curve of the material, allowing a cycle by cycle estimation of the residual lifespan. However, it remains non-conservative at low effort. The proposed model, based on Chaboche law, overcomes some of its theoretical drawbacks, notably the dependence on the calibration parameters of the SN curve. By fitting this curve within a specific calibration window, the model improves forecast accuracy by taking into account parameter variability. This proposed model provides more reliable lifespan predictions that better correlate with experimental results, especially for low effort levels where Miner's law fails. The validation approach is based on comparing the predictions of the damage laws with the experimental results, by evaluating the deviation from the first bisector of the graphs. The results show that Miner's law is unsuitable for effort levels, while the proposed model turns out to be the most precise and conservative. The law of Mesmacque and Amrouche falls between the two, presenting a certain justice but remaining overall non-conservative. In conclusion, the proposed model offers a better match with experimental data, making its predictions more reliable for industrial applications.
Abstract: The article examines the validity of the laws for predicting the life of welded points under variable amplitude loading, using three steels (HE360D, XE360D and XES) supplied by ArcelorMittal to Renault for the manufacture of automobile chassis parts. The fatigue tests revealed two modes of failure: cracking of the sheets at medium stresses and shea...
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Research Article
Energy Recovery of Waste (Banana Peels, Mango Peels and Orange Peels) for the Production of Ecological Charcoal in the Republic of Guinea
Issue:
Volume 12, Issue 4, December 2024
Pages:
94-102
Received:
11 October 2024
Accepted:
31 October 2024
Published:
22 November 2024
DOI:
10.11648/j.ajee.20241204.12
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Abstract: This research aimed at the production of ecological charcoal from banana, mango and orange peel waste. These wastes were collected among the household solid waste of the city of Kindia, 135 km from Conakry. The methodology approach consists of: sorting and identifying the types of waste, producing ecological coal through the following steps (waste drying, carbonization, grinding, sieving, mixing, adding binders, molding, compacting and drying coal briquettes). The manufactured coal briquettes were characterized for the determination of moisture content, ash content, volatile matter content, carbon content and calorific value). The main results obtained are: (i) For the initial masses of waste, banana peels (5 kg), mango peels (2.532 kg), orange peels (1.68 kg); we obtained the masses of coal briquettes made from banana peels (0.328 kg), from mango peels (0.123 kg) and from orange peels (0.237 kg); (ii) the physicochemical characterization of the charcoal briquette samples gave a carbon content of charcoal briquettes made from mango peels (45.47%), charcoal briquettes made from orange peels (44.49%) and charcoal briquettes made from orange peels (29.95%); the humidity content of banana peel briquettes is 30.74%, briquettes made from mango peels (12.19%) and briquettes made from orange peels (12.33%); the ash content of charcoal briquettes made from banana peels (17.74%), from banana peels (9.67%) and orange peels (11.14%); the volatile matter rates of charcoal briquettes made from mango peels (90.33%), orange peels (88.86%) and banana peels (82.21%); the calorific value of charcoal briquettes made from banana peels (6580.8 kcal/kg), from mango peels (7226.4 kcal/kg) and from orange peels (7108.8 kcal/kg). Ecological charcoal briquettes are produced locally using less expensive materials and tools, which is an advantage for households in terms of energy, environment and economy.
Abstract: This research aimed at the production of ecological charcoal from banana, mango and orange peel waste. These wastes were collected among the household solid waste of the city of Kindia, 135 km from Conakry. The methodology approach consists of: sorting and identifying the types of waste, producing ecological coal through the following steps (waste ...
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Research Article
Energy Needs and Trends Assessment for the Urban Commune of N’zérékoré, Republic of Guinea
Issue:
Volume 12, Issue 4, December 2024
Pages:
103-113
Received:
29 October 2024
Accepted:
14 November 2024
Published:
29 November 2024
DOI:
10.11648/j.ajee.20241204.13
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Abstract: Nowadays, one of the major problems facing large cities is the adaptation of energy needs with their rapid demographic growth. In most cases, there is a disconnect between the rapid demographic increases and the updating of energy needs. The major cities of the Republic of Guinea are confronted to a significant challenge due to insufficient energy supply for their sustainable development, and the urban commune of N’zérékoré is a clear example of this. The city is experiencing substantial rapid demographic growth, which requires a long-term assessment of its energy needs for its sustainable development. In this paper, a model for projecting energy demand over 10 years for the urban commune of N'zérékoré taking into account its demographic evolution was developed. An estimate of energy needs was made based on the projected population growth from 2024 to 2060. The results show that the urban commune's current energy consumption is estimated at 53.89 MW, or 38.8 GWh per month, while the projected energy demand for the same year amounts to 51.6 GWh. Population growth continuously drives a strong increase in energy demand, if production remains unchanged, by 2060 the commune’s energy need would reach 1,595.16 GWh, resulting in a deficit of 1,543.56 GWh.
Abstract: Nowadays, one of the major problems facing large cities is the adaptation of energy needs with their rapid demographic growth. In most cases, there is a disconnect between the rapid demographic increases and the updating of energy needs. The major cities of the Republic of Guinea are confronted to a significant challenge due to insufficient energy ...
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Djonglibet Wel-Doret*
