2944 Words Apr 21st, 2015 12 Pages
ABSTRACT
Stiffeners are used to reduce the probability of local failures in structures. Local stiffening is a matter of interest in aerospace, civil, and mechanical engineering. In spite of the presence of local stiffeners in different structures, the analysis of stiffened frames is scarce in the literature. The effect of local stiffeners on the stability of frame structures is investigated in this paper using detailed modelling of columns. A stiffener reduces the flexibility of a stiffened column. It is a common practice to model a stiffened column by a system of springs in series. This system is not suitable for simulating stiffness in finite element models. Consequently, this has been replaced by an equivalent parallel spring system.
Eigenvalue
Eigenvalue buckling analysis predicts the theoretical buckling strength of an ideal elastic structure. It computes the structural eigenvalues for the given system loading and constraints. This is known as classical Euler buckling analysis. Buckling loads for several configurations are readily available from tabulated solutions. However, in real-life, structural imperfections and nonlinearities prevent most real-world structures from reaching their eigenvalue predicted buckling strength; ie. it over-predicts the expected buckling loads. This method is not recommended for accurate, real-world buckling prediction analysis. 2. Nonlinear
Nonlinear buckling analysis is more accurate than eigenvalue analysis because it employs non-linear, large-deflection; static analysis to predict buckling loads. Its mode of operation is very simple: it gradually increases the applied load until a load level is found whereby the structure becomes unstable (ie. suddenly a very small increase in the load will cause very large deflections). The true non-linear nature of this analysis thus permits the modeling of geometric imperfections, load perturbations, material nonlinearities and gaps. For this type of analysis, note that small off-axis loads are necessary to initiate the desired buckling mode.
This will use a steel beam with a 10 mm X 10 mm cross section, rigidly constrained at the bottom. The required load to cause buckling, applied at the top-center of the

## Related Documents

• ###### Essay The Shape Of The System At Point 1 And 2

the column. It can be seen that the system moment is zero in a variety of places over the course of the loading. One place the moment it zero here is at L/2. The moment at L/2 is only zero during line-contact. Due to the symmetric nature of the buckling sequence, line-contact repeats here throughout the course of loading. Figure 5.12 Shapes of 6in3w column undergoing 1-2 modal transition with areas with 0 moment highlighted in red Below is the simulation for the bi-laterally constrained column…

Words: 2076 - Pages: 9
• ###### Buckling Lab Essay

Scope: In this lab we studied Buckling. Buckling is one type of failure mode which is related to stability. Buckling is the result of axial compression resulting in a lateral deflection. In this experiment five steal columns with different lengths 25-5 “in” are being under axial compression forming buckling. Buckling can occur in any compressive structure and should always be considered in design. Significance: Columns are one type of the commonly used structure in bridges and building to support…

Words: 683 - Pages: 3
• ###### Essay My Experience At Super Speed

United States. Ever since I was little my parents would not put the car in drive unless I was wearing my seatbelt. It was just something I grew up on and as I grew older and my siblings could drive me around, I noticed how some of them had stopped buckling up; which I always told them to do because in my mind it still made sense to wear the seatbelts, I mean they were manufactured and placed in the car for a reason. As the paramedics were trying to help me calm my breathing down and talk me through…

Words: 1090 - Pages: 5
• ###### Minimum Weight Design of a Wing Box Subjected to Bending Essay

largely controlled by the buckling of the compression cover plate. In order to get a minimum weight design of such a box the compression cover skin and its support arrangements are to be selected so as to give highest buckling stress. In this project an ideal box beam representative of a wing torsion box will be considered for a detailed analysis. The box beam subjected to a bending moment, various structural arrangements will be considering in order maximising the buckling stress. An analytical formulation…

Words: 3662 - Pages: 15
• ###### Essay Cosmetic Use Of Botulinum Toxin Type A

et al., 2008). The human skin consist of five different layers: the three dermis layers, the hypodermis and the stratum corneum (Kuwazuru et al., 2008). Damage to the skin is described as a multistage buckling theory; where the upper layer gets damaged and the lower layers will experience buckling against the larger compression (Kuwazuru et al., 2008). Pharmacokinetics Following the injection of BTX-A, it is expected to not be present in peripheral blood at measurable levels (Hurkadle et al., 2012)…

Words: 2173 - Pages: 9
• ###### Essay Solutions For The Compression Column

design. Buckling is a form of instability found in all compressive structures, and as this instability increases due to material and geometric properties, preventing it becomes a major hurdle. Unstable collapse of systems is a widely studied field relevant to systems large and small, from preventing building collapse during an earthquake to the buckling of fibers within a composite. Compression members of certain material properties and long slender geometries can be susceptible to buckling. While…

Words: 1887 - Pages: 8

This is view one way by Euler’s Buckling Theory. At the end of a boomilever’s life, once it has reached the maximum weight it can bear, it will inevitably begin to break. In this case, the wood and glue has reached what is called a failure mode, specifically known as buckling. In 1757, a theory was developed by a mathematician, Leonhard Euler, that explains how much a column, or straight structure can bear before reaching said failure mode. Known as Euler’s Buckling Theory, it is: Where F is the…

Words: 1290 - Pages: 6
• ###### Essay The Boxing Match Between Tommy Burns And Jack Johnson

very powerful and destructive audience. There are also many overpowering angles displaying tension for the white culture. For example, it clearly highlights burns’ right leg buckling inward which shows that he is collapsing backward. This angle also demonstrates the overpowering actions of Johnson. Johnsons knee is buckling forward sending his whole body in an aggressive motion toward burns. The angles, lighting, and colors completely define Bellows opinion and statement of this painting. It also…

Words: 1303 - Pages:
• ###### Essay Steps And Objectives Of Bridges

an electronic balance. The mass at which it buckles is noted and converted to force. Compressive strength = Max Load/Area Design 1 At length = 10.96 Max load for buckling applied = 2.2 Kg = 21.58N Area = π (3)2-π (2.95)2 = 0.935 mm2 S= P/A = 21.58/0.935 = 23.08 N/mm2 At length = 16 Max load for buckling applied = 1.9Kg = 18.64N S= P/A = 18.64/0.935 = 19.94 N/mm2 Safety Factor Safety factor describes how much stronger the bridge is than it usually…

Words: 1918 - Pages: 8
• ###### The Continuous Floating Constraint And Buckling Column Concept

The past chapter proposed the continuous floating constraint and buckling column concept. In this chapter, a test setup is proposed to investigate its loading nature and validate the concept. A series of tests are performed, and the results are presented and discussed. The results of the tests conducted in this chapter will serve as measures in assessing the strengths and flaws of the initial concept, and point towards potential solutions. This group of tests varied two geometric parameters:…

Words: 2242 - Pages: 9