Derivation of the secant stiffness matrix for non linear finite element analysis of solids and trusses

==1 Title, abstract and keywords<!-- Your document should start with a concise and informative title. Titles are often used in information-retrieval systems. Avoid abbreviations and formulae where possible. Capitalize the first word of the title.

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==2 The main text<!-- You can enter and format the text of this document by selecting the ‘Edit’ option in the menu at the top of this frame or next to the title of every section of the document. This will give access to the visual editor. Alternatively, you can edit the source of this document (Wiki markup format) by selecting the ‘Edit source’ option.

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2.1 Subsections

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==3 Bibliography<!-- 
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==4 Acknowledgments<!-- Acknowledgments should be inserted at the end of the document, before the references section. -->==




==5 References<!--[1] Author, A. and Author, B. (Year) Title of the article. Title of the Publication. Article code. Available: http://www.scipedia.com/ucode.

[2] Author, A. and Author, B. (Year) Title of the article. Title of the Publication. Volume number, first page-last page.

[3] Author, C. (Year). Title of work: Subtitle (edition.). Volume(s). Place of publication: Publisher.

[4] Author of Part, D. (Year). Title of chapter or part. In A. Editor & B. Editor (Eds.), Title: Subtitle of book (edition, inclusive page numbers). Place of publication: Publisher.

[5] Author, E. (Year, Month date). Title of the article. In A. Editor, B. Editor, and C. Editor. Title of published proceedings. Paper presented at title of conference, Volume number, first page-last page. Place of publication.

[6] Institution or author. Title of the document. Year. [Online] (Date consulted: day, month and year). Available: http://www.scipedia.com/document.pdf. 
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