Fixturing of Compliant Parts Using a Matrix of Reconfigurable Pins

1999 ◽  
Vol 122 (4) ◽  
pp. 766-772 ◽  
Author(s):  
Daniel F. Walczyk ◽  
Randy S. Longtin
Keyword(s):  
Low Cost ◽  
Metal Composite ◽  
Lateral Loads ◽  
Load Carrying ◽  
Mechanical Models ◽  
Computer Controlled ◽  
Compliant Parts ◽  
Plastic Parts ◽  
Machining Operations ◽  
Rigid Platen

Commercially-available reconfigurable fixtures, used for holding compliant sheet metal, composite and plastic parts during secondary machining operations, are extremely expensive and overly-complicated devices. A computer-controlled, reconfigurable fixturing device (RFD) concept for compliant parts, based on a matrix of individually-stoppable pins lowered by a single rigid platen, has been developed as a simple and low-cost design alternative to commercially-available devices. Two different approaches to stopping and clamping individual pins have been investigated: a combination electromagnet assist and gas springs compressed with a toggle mechanism, and a pneumatic clamp. Simple mechanical models have been developed for predicting the stopping and clamping performance of both designs including pin positioning accuracy, vertical load-carrying capacity of a pin, and deflection of a pin subjected to lateral loads. An RFD prototype, consisting of a single pin actuated by a servoed platen, has been designed, built and tested. It has demonstrated the feasibility of this new RFD design. [S1087-1357(00)02204-8]

Low-Cost Load-Carrying Devices

1995 ◽  
Author(s):  
Ron Dennis ◽  
Alan Smith
Keyword(s):  
Low Cost ◽  
Load Carrying

A Study on the Birefringence Measurement in Injection Molded Parts Using Two Different Laser Sources and R-G-B Separation of White Light

2006 ◽  
Vol 326-328 ◽  
pp. 187-190
Author(s):  
Jong Sun Kim ◽  
Chul Jin Hwang ◽  
Kyung Hwan Yoon
Keyword(s):  
White Light ◽  
Low Cost ◽  
Main Idea ◽  
Injection Molding Process ◽  
Molding Process ◽  
Laser Method ◽  
High Productivity ◽  
Molded Parts ◽  
Injection Molded ◽  
Plastic Parts

Recently, injection molded plastic optical products are widely used in many fields, because injection molding process has advantages of low cost and high productivity. However, there remains residual birefringence and residual stresses originated from flow history and differential cooling. The present study focused on developing a technique to measure the birefringence in transparent injection-molded optical plastic parts using two methods as follows: (i) the two colored laser method, (ii) the R-G-B separation method of white light. The main idea of both methods came from the fact that more information can be obtained from the distribution of retardation caused by different wavelengths. The comparison between two methods is demonstrated for the same sample of which retardation is up to 850 nm.

Low-Cost Lightweight Thin Film Solar Concentrators

2014 ◽  
Author(s):  
Gani B. Ganapathi ◽  
Art Palisoc ◽  
Bill Nesmith ◽  
Gyula Greschik ◽  
Koorosh Gidanian ◽  
...  
Keyword(s):  
Technology Development ◽  
Deep Structure ◽  
Low Cost ◽  
Development Program ◽  
Cost Benefit ◽  
Rigid Foam ◽  
Bird Droppings ◽  
Load Carrying ◽  
Pointing Accuracy ◽  
The Cost

A low-cost rigid foam-based concentrator technology development program was funded by the DOE SunShot Initiative to meet installed cost goals of $75/m2 vs. current costs of $200–250/m2. The cost reduction in this approach focuses primarily on designing a mirror module with a rigid foam center with stainless steel facesheets and reflective film. The low mechanical strength of the foam is compensated by optimizing the densities and dimensions to meet pointing accuracy requirements of 4 milliradians (mrad) in 27mph winds. Two alpha concentrators were built to validate the mirror module manufacturing process and one of them was accurate to 0.15 mrad RMS vs. the design requirement of 1 mrad RMS. To understand the lifetime reliability of the panels, fifteen 4-inch square samples were exposed to various environmental conditions including acid rain, bird droppings, thermal cycling, and the final results indicated no loss in reflectivity of 95%. UV testing will be performed in the next phase. Three mechanical structure options covering the range of large multi-faceted heliostats with diagonal load carrying elements, small single facet heliostats low to the ground and optimized truss-based deep structure designs were analyzed with FEA and analytically; results indicated a significant cost benefit (>2×) for the truss-based design over the other options. Other elements such as the controls, actuators were also considered in th analysis with vendor data. Cost trades were performed for heliostats ranging from 10m2 to 250m2. The results indicated a broad installed cost minimum around $113/m2 for heliostat sizes ranging from 80 m2 to 130 m2. Additional cost saving approaches will be considered in Phase 2 of the project.

Design of Compliant Bamboo Poles for Carrying Loads

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Karna Potwar ◽  
Jeffrey Ackerman ◽  
Justin Seipel
Keyword(s):  
Low Cost ◽  
Material Design ◽  
The Body ◽  
Load Carriage ◽  
Design Parameters ◽  
Beam Model ◽  
Load Carrying ◽  
Predictive Design ◽  
Force Reduction ◽  
Heavy Loads

Carriage of heavy loads is common in developing countries and can impart large repetitive forces on the body that could lead to musculoskeletal fatigue and injury. Compliant bamboo poles have been used to carry heavy loads in Asia for generations and could be a low-cost, sustainable, and culturally acceptable way to minimize the forces acting on the body during load carriage. Experimental evidence of running with a 15 kg load suspended from a pair of compliant poly(vinyl chloride), or PVC, poles shows that the poles act as a vibration-isolating suspension, which can reduce the peak forces on the body during locomotion. However, it is currently not well-understood how to design and optimize poles for load carrying such that the peak forces on the body are minimized during carrying. Further, current users of bamboo poles do not have a reliable way to measure forces on the body and so cannot empirically optimize their poles for force reduction. Our objective is to determine the geometric and material design parameters that optimize bamboo poles for load carriage and to develop recommendations that could make it easier for load carriers to fabricate well-suited poles. Our approach is to synthesize a predictive model of walking and running from the field of biomechanics, which can predict the peak forces on the body as a function of pole stiffness, with a bending beam model of the bamboo pole that relates pole geometry and material to the effective pole stiffness. We first check our model's ability to predict the experimental results from a well-established study with PVC poles. We then extend the predictive design study to include a wider range of stiffness values and pole geometries that may be more effective and realistic for practical load carrying situations. Based on stiffness, deflection, strength, and pole mass design constraints, we specify an appropriate range of dimensions for selecting bamboo poles to carry a 15 kg load. The design methodology presented could simplify the selection and design of bamboo carrying poles in order to reduce the likelihood of musculoskeletal injury.

A Low Cost Computer Controlled IC Engine Test Facility

1998 ◽  
Vol 31 (4) ◽  
pp. 105-109
Author(s):  
Z. Ren ◽  
T. Campbell ◽  
J. B. Yang
Keyword(s):  
Low Cost ◽  
Test Facility ◽  
Engine Test ◽  
Ic Engine ◽  
Computer Controlled

Experimental and Numerical Investigation on the Load Carrying Behavior of Large Ship Windows

2014 ◽  
Author(s):  
Wolfgang Fricke ◽  
Bjarne Gerlach ◽  
Matthias Guiard
Keyword(s):  
Ultimate Load ◽  
Impact Loads ◽  
Test Results ◽  
Lateral Loads ◽  
Load Range ◽  
Filled Rubber ◽  
Load Carrying ◽  
Drop Tests ◽  
Load Tests ◽  
The Impact

Aboard ships windows are exposed to static as well as dynamic loads, e.g. impact loads. Failure can lead to serious consequences. Therefore two research projects were initiated in order to analyze the load carrying behavior of windows. In addition to quasi-static ultimate load tests and drop tests with water filled rubber bags special attention is paid to the Finite Element (FE) modeling. In particular the response — stresses and deformations — to quasi-static lateral loads can be calculated with good agreement to test results. Hence FE calculations can be useful to determine and compare failure mechanisms of different window designs. An ultimate load range can be estimated by taking into account the breaking strength range of glass. A comparison between FE calculations and results of the impact tests showed that these are sensitive to conditions which could hardly be measured during the test, e.g. the shape of the approaching water-filled rubber bag. Varying of parameters eventually yielded that window response to impact loads can also be calculated sufficiently, at least, to evaluate different window designs. Further investigations on this topic are in progress.

scholarly journals A Ligature Model for Fiber Reinforced Porous Composites

1998 ◽  
Vol 7 (5) ◽  
pp. 096369359800700
Author(s):  
Xinyu Huang ◽  
Ken L. Reifsnider
Keyword(s):  
Life Prediction ◽  
Porous Matrix ◽  
Fiber Reinforced ◽  
Porous Fiber ◽  
Reinforced Composite ◽  
Filament Wound ◽  
Effective Media ◽  
Load Carrying ◽  
Mechanical Models ◽  
Porous Composites

The authors have developed a modeling approach that has the ability to analyze porous fiber reinforced composite materials. The meso-level geometry is modeled by ligatures and effective media. Ligatures represent fiber tows, the major load-carrying components in the material. Effective media represent the porous matrix. The properties of the ligatures and effective media come from micro-mechanical models. Global stiffness can be successfully predicted. Residual strength and life prediction could also be made from this representation. The approach is validated by an example calculation for a filament wound tubular structure with porosity of the order of 60 percent.

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