Structural Analysis of High-End Server Computer Frames Under Earthquake Loading

2004 ◽  
Author(s):  
Shawn Canfield ◽  
Budy D. Notohardjono
Keyword(s):  
Structural Analysis ◽  
Mechanical Design ◽  
Experimental Testing ◽  
Design Study ◽  
Element Analysis ◽  
Step Process ◽  
Server Systems ◽  
Experimental Correlation ◽  
Vibration Tests ◽  
Frame Rigidity

This paper reports the mechanical design, structural analysis, and experimental correlation of bracing concepts for high-end computer servers subjected to loads simulating earthquake conditions. The development and evaluation of these stiffening alternatives follows a step-by-step process of finite element analysis coupled with parallel experimental testing. The numerical model is derived from the simplified CAD geometry of an existing server frame. An analysis of this frame model is subjected to a load environment similar to those endured under actual horizontal table vibration tests. The result of this series of analyses is a design study examining how a range of bracing designs affects the global frame rigidity. This design study builds toward the objective of constructing a verified model of the server frame and components that will lead to a guideline for implementing stiffener designs on high-end server systems.

Dynamic Analysis of HSDB System and Evaluation of Boundary Non-linearity through Experiments

2016 ◽  
Vol 66 (3) ◽  
pp. 210
Author(s):  
K. Chandrakar ◽  
P.L. Venkateshwara Rao ◽  
P. Rajendran ◽  
C. Satyanarayana
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
High Speed ◽  
Printed Circuit Board ◽  
Structural Integrity ◽  
Mechanical Design ◽  
Circuit Board ◽  
Element Analysis ◽  
Maximum Acceleration ◽  
Vibration Tests

<p class="FAIMTextBody">This paper deals with mechanical design and development of high speed digital board (HSDB) system which consists of printed circuit board (PCB) with all electronic components packaged inside the cavity for military application. The military environment poses a variety of extreme dynamic loading conditions, namely, quasi static, vibration, shock and acoustic loads that can seriously degrade or even cause failure of electronics. The vibrational requirement for the HSDB system is that the natural frequency should be more than 200 Hz and sustain power spectrum density of 14.8 Grms in the overall spectrum. Structural integrity of HSDB is studied in detail using finite element analysis (FEA) tool against the dynamic loads and configured the system. Experimental vibration tests are conducted on HSDB with the help of vibration shaker and validated the FE results. The natural frequency and maximum acceleration response computed from vibration tests for the configured design were found. The finite element results show a good correlation with the experiment results for the same boundary conditions. In case of fitment scenario of HSDB system, it is observed that the influence of boundary non-linearity during experiments. This influence of boundary non-linearity is evaluated to obtain the closeout of random vibration simulation results.</p>

Seismic Evaluation of Large Server Computer Structure

2009 ◽  
Author(s):  
Budy D. Notohardjono ◽  
Shawn Canfield ◽  
James A. Cooke
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Experimental Testing ◽  
Element Model ◽  
Frame Structure ◽  
Seismic Evaluation ◽  
Modal Data ◽  
Server Systems ◽  
Computer Structure ◽  
Vibration Tests

This paper discusses the analysis and verification of a finite element model which simulates the robustness of a high end computer server structure during a severe seismic event. The server consists of the frame which is the structure that components are installed into, such as processor units, input-output units and power components. The finite element modeling of this server frame is presented here not only to inform on creating an accurate model for simulation purposes, but also to provide guidelines as to the critical factors in setting up a large assembly finite element model (FEM) and to establish the optimum methodology for modeling this complex assembly with the available analysis software tools. For verification, the simulated modal data is compared to both modal data measured from an instrumented impact hammer, and to measured swept sine data. The simulated results compare favorably with the measured data, and it has been determined that location and integrity of the welded connections are critical for an accurate vibration response of the finite element model. The analysis frame model was subjected to loads and environmental conditions similar to those endured under horizontal table vibration tests and seismic events. The results of the experimental testing and simulations were compared and proved to be in a good correlation. Based on this verified finite element model, any additional redesign of the frame structure and its stiffening members can proceed very efficiently. This design study builds toward the objective of constructing a verified model of the server frame and components which will lead to a guideline for implementing stiffener designs on high-end server systems.

scholarly journals Mechanical design, analysis and testing of a large-range compliant microgripper

2016 ◽  
Vol 7 (1) ◽  
pp. 119-126 ◽  
Author(s):  
Yilin Liu ◽  
Qingsong Xu
Keyword(s):  
Large Range ◽  
Mechanical Design ◽  
Experimental Testing ◽  
Design Analysis ◽  
Element Analysis ◽  
Amplification Ratio ◽  
Testing Procedures ◽  
Dual Stage ◽  
Fea Simulation ◽  
Simulation Results

Abstract. This paper presents the mechanical design, analysis, fabrication, and testing procedures of a new large-range microgripper which is based on a flexible hinge structure. The uniqueness of the gripper is that the gripper arms not only provide large gripping range but also deliver approximately rectilinear movement as the displacement in nonworking direction is extremely small. The large gripping range is enabled by a mechanism design based on dual-stage flexure amplifier to magnify the stroke of piezoelectric actuator. The first-stage amplifier is a modified version of the Scott Russell (SR) mechanism and the second-stage amplifier contains a parallel mechanism. The displacement amplification ratio of the modified SR mechanism in the gripper has been enlarged to 3.56 times of the conventional design. Analytical static models of the gripper mechanism are developed and validated through finite-element analysis (FEA) simulation. Results show that the gripping range is over 720 µm with a resonant frequency of 70.7 Hz and negligible displacement in nonworking direction. The total amplification ratio of the input displacement is 16.13. Moreover, a prototype of the gripper is developed by using aluminium 7075 for experimental testing. Experimental results validate the analytical model and FEA simulation results. The proposed microgripper can be employed in various microassembly applications such as pick-and-place of optical fibre.

Structural analysis of wing ribs obtained by additive manufacturing

2019 ◽  
Vol 25 (4) ◽  
pp. 708-720 ◽  
Author(s):  
Pedro Miguel Cardoso Carneiro ◽  
Pedro Gamboa
Keyword(s):  
Additive Manufacturing ◽  
Structural Analysis ◽  
Fused Deposition Modeling ◽  
Experimental Testing ◽  
Experimental Tests ◽  
Limiting Factor ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Content Type ◽  
Fused Deposition

Purpose Additive manufacturing (AM) has emerged over the past years as a key technology in aircraft structural components’ manufacturing. This paper aims to describe the numerical analysis and experimental testing of five wing ribs with different 2D topologies manufactured with polylactic acid (PLA) using the fused deposition modeling technology. The main purpose is to determine the best wing rib topology in terms of strength, stiffness and mass. Design/methodology/approach Numerical analyses are performed using Ansys Workbench’s static structural analysis for two distinct loading cases. In the first loading, the chord-wise distributed load, resulting from wing lift, is replaced by two equivalent concentrated loads at the leading and trailing edges. This simplification allows the numerical results to be experimentally validated. The second loading has distributed loads applied on the upper and on the lower surfaces of the wing rib to produce a more realistic structural response. Experimental tests are performed with the first loading case to determine maximum displacement and failure loads of the wing ribs studied. SEM is used to analyze fracture surfaces. Findings From the five different PLA printed wing rib topologies studied, it is found that truss type configurations are the more structural efficient, that is, truss topologies exhibit better specific strength and specific stiffness. Additionally, the limiting factor in the design of these wing ribs is stiffness rather than strength. Originality/value The work identifies the kind of structural topologies that are best suited for 2D wing ribs obtained by AM and leads the way to more complex and more efficient structural layouts to be explored in the future using topology optimization coupled with simple Finite Element Analysis (FEA).

scholarly journals Design of a Unique Device for Residual Stresses Quantification by the Drilling Method Combining the PhotoStress and Digital Image Correlation

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 314
Author(s):  
Miroslav Pástor ◽  
Martin Hagara ◽  
Ivan Virgala ◽  
Adam Kaľavský ◽  
Alžbeta Sapietová ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Experimental Testing ◽  
Digital Processing ◽  
Image Correlation ◽  
Optical Systems ◽  
Hole Drilling ◽  
Element Analysis ◽  
Thin Specimen ◽  
Comparison Of The Results

This paper presents a uniquely designed device combining the hole-drilling technique with two optical systems based on the PhotoStress and digital image correlation (DIC) method, where the digital image correlation system moves with the cutting tool. The authors aimed to verify whether the accuracy of the drilled hole according to ASTM E837-13a standard and the positioning accuracy of the device were sufficient to achieve accurate results. The experimental testing was performed on a thin specimen made from strain sensitive coating PS-1D, which allowed comparison of the results obtained by both methods. Although application of the PhotoStress method allows analysis of the strains at the edge of the cut hole, it requires a lot of experimenter’s practical skills to assess the results correctly. On the other hand, the DIC method allows digital processing of the measured data. However, the problem is not only to determine the data at the edge of the hole, the results also significantly depend on the smoothing levels used. The quantitative comparison of the results obtained was performed using finite element analysis.

scholarly journals Mechanical design and finite element analysis of live working robot for 10kV distribution power systems

2021 ◽  
Vol 183 ◽  
pp. 331-336
Author(s):  
Zhang Liming ◽  
He Yulong ◽  
Xu Shanjun ◽  
Zhang Tong ◽  
Guo Junlong ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Power Systems ◽  
Mechanical Design ◽  
Element Analysis

Thermo-structural analysis of cryogenic tanks with common bulkhead configuration

2021 ◽  
pp. 095441002110247
Author(s):  
S Sumith ◽  
R Ramesh Kumar
Keyword(s):  
Structural Analysis ◽  
Temperature Gradient ◽  
Thermal Gradient ◽  
Load Transfer ◽  
Thermal Analyses ◽  
Positive Margin ◽  
Heat Transfer Analysis ◽  
Liquid Oxygen ◽  
Launch Vehicles ◽  
Element Analysis

In launch vehicles, cryogenic propulsion stages store liquid oxygen (LOX) at 76 K and liquid hydrogen (LH2) at 20 K, generally in two separate insulated tanks connected through tubular truss components. Consequently, load transfer from the LH2 tank to the LOX tank is very much localized, resulting in a nonoptimal design. This article presents an alternative single tankage design using a common bulkhead (CBH) to enhance the payload capability, which enables maintaining LH2 temperature within a specified temperature when exposed to a temperature gradient. A sandwich insulator using aramid honeycomb embedded with polyimide foam keeps the LH2 temperature within 20 ± 1 K is proposed, based on transient heat transfer analysis for 1000 s. The foam-filled honeycomb core is treated as equivalent foam in the analysis as the thermal conductivity of the core and the foam is quite close. The efficacy of the insulator is established by an experiment to measure the back wall temperature when liquid nitrogen is loaded on the top skin of the panel, and the insulator maintains a temperature gradient of 123 K for 1000 s. A good agreement is obtained between the transient finite element analysis results with experimental data. An externally insulated LOX tank configuration with an optimum length of the skirt–cylinder where the temperature reaches 80 K is arrived at based on slosh, buckling, and thermal analyses. No thermal gradient is found across the thickness of the skirt, while the thermal gradient is observed along the length of the skirt as anticipated. An integrated thermo-structural analysis of the cryo-system is carried out considering temperature-dependent material properties. A positive margin for the skirt is obtained. A payload gain of 366 kg is estimated based on the present study for the new design option with a CBH and skirt as compared to the traditional tubular truss arrangements.

On-Site Experimental Testing to Study the Vibration of Composite Floors

2014 ◽  
Vol 601 ◽  
pp. 231-234
Author(s):  
Cristian Lucian Ghindea ◽  
Dan Cretu ◽  
Monica Popescu ◽  
Radu Cruciat ◽  
Elena Tulei
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Testing ◽  
Concrete Slab ◽  
Human Perception ◽  
Experimental Tests ◽  
International Standards ◽  
Structural Element ◽  
Element Analysis ◽  
Floor Slabs ◽  
Composite Floors

As a general trend, in order to reduce material consumption or to reduce the mass of the structures, composite floor slabs solutions are used to achieve large spans floor slabs. This solutions led to floors sensitive to vibrations induced generally by human activities. As a verification of the design concepts of the composite floors, usually, it is recommended a further examination of the floor after completion by experimental tests. Although the experimental values of the dynamic response of the floor are uniquely determined, the processing can take two directions of evaluation. The first direction consist in determining the dynamic characteristics of the floor and their comparison with the design values. Another way that can be followed in the processing of the experimental results is to consider the human perception and comfort to the vibration on floors. The paper aims to present a case study on a composite floor, with steel beams and concrete slab, tested on-site. Both aspects of data processing are analyzed, in terms of the structural element, and in terms of the effect on human perception and comfort. Experimentally obtained values for the dynamic characteristics of the floor are compared with numerical values from finite element analysis, while the second type of characteristic values are compared with various human comfort threshold values found in international standards.

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