Finite element analysis of a composite sandwich beam subjected to a four point bend
- Authors: Hove, Darlington
- Date: 2011
- Subjects: Sandwich construction -- Mathematical models , Composite materials -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10503 , http://hdl.handle.net/10948/1465 , Sandwich construction -- Mathematical models , Composite materials -- Research
- Description: The work in this dissertation deals with the global structural response and local damage effects of a simply supported natural fibre composite sandwich beam subjected to a four-point bend. For the global structural response, we are investigating the flexural behaviour of the composite sandwich beam. We begin by using the principle of virtual work to derive the linear and nonlinear Timoshenko beam theory. Based on these theories, we then proceed to develop the respective finite element models and then implement the numerical algorithm in MATLAB. Comparing the numerical results with experimental results from the CSIR, the numerical model correctly and qualitatively recovers the underlying mechanics with some noted deviances which are explained at the end. The local damage effect of interest is delamination and we begin by reviewing delamination theory with more emphasis on the cohesive zone model. The cohesive zone model relates the traction at the interface to the relative displacement of the interface thereby creating a material model of the interface. We then carry out a cohesive zone model delamination case study in MSC.Marc and MSC.Mentat software packages. The delamination modelling is carried out purely as a numerical study as there are no experimental results to validate the numerical results.
- Full Text:
- Date Issued: 2011
- Authors: Hove, Darlington
- Date: 2011
- Subjects: Sandwich construction -- Mathematical models , Composite materials -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10503 , http://hdl.handle.net/10948/1465 , Sandwich construction -- Mathematical models , Composite materials -- Research
- Description: The work in this dissertation deals with the global structural response and local damage effects of a simply supported natural fibre composite sandwich beam subjected to a four-point bend. For the global structural response, we are investigating the flexural behaviour of the composite sandwich beam. We begin by using the principle of virtual work to derive the linear and nonlinear Timoshenko beam theory. Based on these theories, we then proceed to develop the respective finite element models and then implement the numerical algorithm in MATLAB. Comparing the numerical results with experimental results from the CSIR, the numerical model correctly and qualitatively recovers the underlying mechanics with some noted deviances which are explained at the end. The local damage effect of interest is delamination and we begin by reviewing delamination theory with more emphasis on the cohesive zone model. The cohesive zone model relates the traction at the interface to the relative displacement of the interface thereby creating a material model of the interface. We then carry out a cohesive zone model delamination case study in MSC.Marc and MSC.Mentat software packages. The delamination modelling is carried out purely as a numerical study as there are no experimental results to validate the numerical results.
- Full Text:
- Date Issued: 2011
Where leaders learn: constructions of leadership and leadership development at Rhodes University
- Authors: Andrews, Rushda Ruth
- Date: 2011
- Subjects: Leadership -- Education (Higher) -- South Africa -- Grahamstown Leadership -- Research -- South Africa -- Grahamstown Development leadership -- Education (Higher) -- South Africa -- Grahamstown Rhodes University -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:782 , http://hdl.handle.net/10962/d1003903
- Description: This thesis explores the Where Leaders Learn slogan of Rhodes University. It does this by means of an analysis of discourses constructing leadership and leadership development within the institutional context. The discourse analysis was made possible as a result of interviews with a range of people involved in leadership and leadership development at the University. The analysis revealed that leadership development is constructed as taking place within a highly structured system that enables instructional and managerial leadership but constrains transformational leadership. The discourses that give meaning and understanding to the construct of leadership draw heavily on position within a hierarchy. The discourse of functional efficiency is enabled through practices related to reward, recognition, succession planning and mentorship which all serve to replicate the existing leadership structures creating more of the same and in essence stifling the potential for emancipatory leadership. The analysis also shows that a discourse of collegiality serves to create a false sense of a common understanding of leadership in the light of evidence of uncertainty and contestation around the meaning of the slogan Where Leaders Learn and, by association, the very construct of leadership. The discursive process of understanding leadership and developing an institutional theory for the purposes of infusing this into a curriculum poses many challenges. Barriers to new ways of thinking reside within the researchers' ontological and epistemological commitments. This amplifies the need for a more reflective ontology towards leadership and its consequences, especially so in a multidisciplinary environment such as Rhodes University.
- Full Text:
- Date Issued: 2011
- Authors: Andrews, Rushda Ruth
- Date: 2011
- Subjects: Leadership -- Education (Higher) -- South Africa -- Grahamstown Leadership -- Research -- South Africa -- Grahamstown Development leadership -- Education (Higher) -- South Africa -- Grahamstown Rhodes University -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:782 , http://hdl.handle.net/10962/d1003903
- Description: This thesis explores the Where Leaders Learn slogan of Rhodes University. It does this by means of an analysis of discourses constructing leadership and leadership development within the institutional context. The discourse analysis was made possible as a result of interviews with a range of people involved in leadership and leadership development at the University. The analysis revealed that leadership development is constructed as taking place within a highly structured system that enables instructional and managerial leadership but constrains transformational leadership. The discourses that give meaning and understanding to the construct of leadership draw heavily on position within a hierarchy. The discourse of functional efficiency is enabled through practices related to reward, recognition, succession planning and mentorship which all serve to replicate the existing leadership structures creating more of the same and in essence stifling the potential for emancipatory leadership. The analysis also shows that a discourse of collegiality serves to create a false sense of a common understanding of leadership in the light of evidence of uncertainty and contestation around the meaning of the slogan Where Leaders Learn and, by association, the very construct of leadership. The discursive process of understanding leadership and developing an institutional theory for the purposes of infusing this into a curriculum poses many challenges. Barriers to new ways of thinking reside within the researchers' ontological and epistemological commitments. This amplifies the need for a more reflective ontology towards leadership and its consequences, especially so in a multidisciplinary environment such as Rhodes University.
- Full Text:
- Date Issued: 2011
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