Characterising the effect of springback on mechanically formed steel plates
- Akinlabi, Esther Titilayo, Matlou, Kagisho, Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Matlou, Kagisho , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Mechanical forming , Springback
- Type: Article
- Identifier: uj:4724 , ISSN 2078-0958 , http://hdl.handle.net/10210/11549
- Description: In the bending operation, springback causes geometrical inaccuracies of bent parts. To curb springback, various factors such as bending parameters and material properties need to be considered. This paper reports the effects of springback on mechanically formed steel plates. Experimental work using circular bending was conducted to analyse the effect of springback on the formed steel sheets. The sheets were bent using a punch and die having a radius of curvature of 120 mm. In addition, the formed samples were characterized through microstructure, microhardness and tensile results. The results revealed an error due to springback of 4.24%. Furthermore, the Vickers microhardness of the formed samples compared to the parent materials shows an increase of 6% while the Ultimate Tensile Strength also increased by 7%. The effects of strain hardening resulting from the bending process led to the increased hardness and strength of the material. The formed samples had elongated grains when compared to the equiaxed grains of the parent material. The increase in the grains can be attributed to the stretching of the material during the bending process.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Matlou, Kagisho , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Mechanical forming , Springback
- Type: Article
- Identifier: uj:4724 , ISSN 2078-0958 , http://hdl.handle.net/10210/11549
- Description: In the bending operation, springback causes geometrical inaccuracies of bent parts. To curb springback, various factors such as bending parameters and material properties need to be considered. This paper reports the effects of springback on mechanically formed steel plates. Experimental work using circular bending was conducted to analyse the effect of springback on the formed steel sheets. The sheets were bent using a punch and die having a radius of curvature of 120 mm. In addition, the formed samples were characterized through microstructure, microhardness and tensile results. The results revealed an error due to springback of 4.24%. Furthermore, the Vickers microhardness of the formed samples compared to the parent materials shows an increase of 6% while the Ultimate Tensile Strength also increased by 7%. The effects of strain hardening resulting from the bending process led to the increased hardness and strength of the material. The formed samples had elongated grains when compared to the equiaxed grains of the parent material. The increase in the grains can be attributed to the stretching of the material during the bending process.
- Full Text:
Improvement of logistics and supply chain management in the cement industry in Nigeria
- Aniki, Abimbola O, Mbohwa, Charles, Akinlabi, Esther Titilayo
- Authors: Aniki, Abimbola O , Mbohwa, Charles , Akinlabi, Esther Titilayo
- Date: 2014
- Subjects: Logistics management , Supply chain management , Cement industry - Nigeria
- Identifier: uj:4744 , ISSN 2078-0958 , http://hdl.handle.net/10210/11730
- Description: Worldwide, Logistics and Supply Chain play important roles and also contribute immensely to the economy of a nation. In this paper, research was conducted to investigate how logistics and supply chains are implemented in cement factories in Nigeria, identify the problem areas and proffer solutions. The study was conducted by administering well-structured questionnaires. According to the investigation, it was confirmed that most of the investigated companies based their logistical system only on road-link transport system for delivering products to their customers or end-users. Furthermore, the survey revealed that 73% of the respondents prefer to continue with the road-link logistics system. Though there is railway infrastructure in the country but due to research finding, the rail system is obsolete due to negligence and poor maintenance on this logistics system. A new railway infrastructure will have to be put in place for effective and efficient operation; and this is going to be costly for individual company to bear.
- Full Text:
- Authors: Aniki, Abimbola O , Mbohwa, Charles , Akinlabi, Esther Titilayo
- Date: 2014
- Subjects: Logistics management , Supply chain management , Cement industry - Nigeria
- Identifier: uj:4744 , ISSN 2078-0958 , http://hdl.handle.net/10210/11730
- Description: Worldwide, Logistics and Supply Chain play important roles and also contribute immensely to the economy of a nation. In this paper, research was conducted to investigate how logistics and supply chains are implemented in cement factories in Nigeria, identify the problem areas and proffer solutions. The study was conducted by administering well-structured questionnaires. According to the investigation, it was confirmed that most of the investigated companies based their logistical system only on road-link transport system for delivering products to their customers or end-users. Furthermore, the survey revealed that 73% of the respondents prefer to continue with the road-link logistics system. Though there is railway infrastructure in the country but due to research finding, the rail system is obsolete due to negligence and poor maintenance on this logistics system. A new railway infrastructure will have to be put in place for effective and efficient operation; and this is going to be costly for individual company to bear.
- Full Text:
Effects of wire electrical discharge machining on fracture toughness of grade 5 titanium alloy
- Madyira, Daniel M., Akinlabi, Esther Titilayo
- Authors: Madyira, Daniel M. , Akinlabi, Esther Titilayo
- Date: 2014
- Subjects: Titanium alloys , Electrical discharge machining , Fracture toughness , Compact tension
- Type: Article
- Identifier: uj:4752 , ISSN 2078-0958 , http://hdl.handle.net/10210/11738
- Description: Grade 5 titanium (Ti6Al4V) is considered as the workhorse material when it comes to automotive and aerospace applications. It is widely referred to as an aerospace alloy and is relatively a new engineering material. The main attraction of this material is its high strength to weight ratio when compared to such common engineering materials such as steel and aluminum alloys. One of the major challenges in the use of this aerospace material is its machinability. Its high strength which is maintained at elevated temperatures, low thermal conductivity, low elastic modulus and high reactivity with oxygen is a perfect recipe for machining challenges. This leads to high tool wear and long production times. Such challenges are sometimes overcome by electrical discharge machining (EDM). Given that titanium is usually applied to mission critical components (gears, shafts, wing sections), it is important to understand the possible effect of wire EDM on their structural performance. One of the structural integrity indicators in such applications is fracture toughness. Fracture toughness is widely used for damage tolerance analysis of aerospace components in which critical crack sizes are computed for given loading conditions to arrive at safe inspection and maintenance intervals. It is therefore the purpose of this paper to conduct a study on the effect of wire EDM on the fracture toughness of this aerospace material. Standard test procedure using compact tension (CT) specimen is used to measure the fracture toughness. Four specimens are produced using wire EDM. This includes the pre-crack which is usually produced by fatigue cycling. Obtained results indicate a slight decrease in fracture toughness compared to that reported in literature. In addition, it can also be concluded that wire EDM can be used as an alternative to fatigue pre-cracking in fracture toughness testing of titanium alloys.
- Full Text:
- Authors: Madyira, Daniel M. , Akinlabi, Esther Titilayo
- Date: 2014
- Subjects: Titanium alloys , Electrical discharge machining , Fracture toughness , Compact tension
- Type: Article
- Identifier: uj:4752 , ISSN 2078-0958 , http://hdl.handle.net/10210/11738
- Description: Grade 5 titanium (Ti6Al4V) is considered as the workhorse material when it comes to automotive and aerospace applications. It is widely referred to as an aerospace alloy and is relatively a new engineering material. The main attraction of this material is its high strength to weight ratio when compared to such common engineering materials such as steel and aluminum alloys. One of the major challenges in the use of this aerospace material is its machinability. Its high strength which is maintained at elevated temperatures, low thermal conductivity, low elastic modulus and high reactivity with oxygen is a perfect recipe for machining challenges. This leads to high tool wear and long production times. Such challenges are sometimes overcome by electrical discharge machining (EDM). Given that titanium is usually applied to mission critical components (gears, shafts, wing sections), it is important to understand the possible effect of wire EDM on their structural performance. One of the structural integrity indicators in such applications is fracture toughness. Fracture toughness is widely used for damage tolerance analysis of aerospace components in which critical crack sizes are computed for given loading conditions to arrive at safe inspection and maintenance intervals. It is therefore the purpose of this paper to conduct a study on the effect of wire EDM on the fracture toughness of this aerospace material. Standard test procedure using compact tension (CT) specimen is used to measure the fracture toughness. Four specimens are produced using wire EDM. This includes the pre-crack which is usually produced by fatigue cycling. Obtained results indicate a slight decrease in fracture toughness compared to that reported in literature. In addition, it can also be concluded that wire EDM can be used as an alternative to fatigue pre-cracking in fracture toughness testing of titanium alloys.
- Full Text:
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