Basic concepts of engineering analysis

Basic concepts of engineering analysis

Analysis of discrete systems The essence of a lumped-parameter mathematical model is that the state of the system can be described directly with adequate precision by the magnitudes of a finite (and usually small) number of state variables. The solution requires the following steps: System idealization: the actual system is idealized as an assemblage of elements Element equilibrium: the equilibrium requirements of each element are established in terms of state variables Element assemblage: the element interconnection requirements are invoked to…

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Finite Element Procedures – Matrix, Vectors, Tensors

Finite Element Procedures – Matrix, Vectors, Tensors

Special Matrix symmetric matrix identity matrix / unite matrix symmetric banded matrix the following matrix is a symmetric banded matrix of order 5 and the half-bandwidth is 2. \[{\rm{A}} = \left[ {\begin{array}{*{20}{c}} 3&2&1&0&0\\ 2&3&4&1&0\\ 1&4&5&6&1\\ 0&1&6&7&4\\ 0&0&1&4&3 \end{array}} \right]\] diagonal matrix: nonzero elements only on the diagonal of the matrix upper half of the matrix inverse matrix, the inverse of a matrix partitioning of matrix the trace and determinant of a matrix: only defined if the matrix is square tr(A)…

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Cheung Chau Island HK 长洲岛

Cheung Chau Island HK 长洲岛

长洲岛,Cheung Chau Island,属于香港十八区之中的离岛区。长洲因岛形狭长,且两头大、中间细,所以被称为长洲。位于香港西南面,面积只有2.4平方公里,居民约三万余人,是离岛区人口最稠密的岛屿。因为抢包山活动而具有知名度,风景很不错。 从中环码头乘船到长洲岛,普通船大概一小时即可到达,交通还算很方便的。

Examples of extracting matrices from ABAQUS

Examples of extracting matrices from ABAQUS

2D frame This is a plane steel frame with box sections subjected to a point load at one node figured as below. An dynamic implicit analysis step was defined and the following lines were added at the end of input file. ** *STEP *MATRIX GENERATE, STIFFNESS, MASS, LOAD, Structural Damping,Viscous Damping *MATRIX OUTPUT, STIFFNESS, MASS, LOAD, Structural Damping,Viscous Damping, FORMAT=COORDINATE *END STEP

Time and Amplitude in ABAQUS

Time and Amplitude in ABAQUS

I am recently using the dynamic analysis in Abaqus, so I decided to summarize the understanding of time and amplitude in it so that I can refer to this article later if needed. Time Step Time: the time period in *STEP definition. Total Time: the sum of all the Step Time. Natural time: actual time that one thing takes. The time in Abaqus/Standard does not have any actual meaning, it can be understood as the relative time. The time in…

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Extract Matrix from ABAQUS

Extract Matrix from ABAQUS

Matrix in ABAQUS Matrices: Stiffness, Mass, Viscous Damping, Structural Damping, Load Formats:  FORMAT=MATRIX INPUT (default) to specify that the output use the matrix input text format that is consistent with the format used by the matrix definition technique in Abaqus/Standard. Set FORMAT=LABELS to specify that the output use the standard labeling format. Set FORMAT=COORDINATE to specify that the output use the common mathematical coordinate format.

LAMMA ISLAND 南丫島 HK

LAMMA ISLAND 南丫島 HK

南丫岛 Lamma Island 是香港的第四大岛屿,但其实感觉并不大,刚上去的时候有种鼓浪屿的感觉,可能海岛都有点类似的感觉吧。虽然天气不好,但看起来还是挺美的。