Investigation of Workpiece Distortion During the Photopolymerization of a PAAW Joint

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Kristopher R. Doll ◽  
Edward C. De Meter
Keyword(s):  
Residual Stresses ◽  
Adhesive Joint ◽  
Load Capacity ◽  
Tensile Force ◽  
Empirical Models ◽  
Thickness Reduction ◽  
Joint Thickness ◽  
A Value ◽  
Tensile Forces ◽  
The Impact

As a workpiece is bonded to a photo-activated adhesive workholding (PAAW) fixture, the adhesive shrinks during photopolymerization. This leads to the buildup of residual stresses that may distort the workpiece or reduce the external load capacity of the adhesive joints. This research quantifies the impact of adhesive shrinkage on fractional thickness reduction and residual tensile force for a commercially available adhesive and gripper. These variables are quantified for typical ranges of adhesive joint thickness and workpiece interface stiffness. Empirical models are presented for relating these variables. This research reveals that once photopolymerization ceases, workpiece distortion and residual stresses are permanent, and are not diminished by adhesive stress relaxation. It also reveals that the fractional thickness reduction of a PAAW joint can range from close to zero to a value equivalent to the fractional volumetric shrinkage of the adhesive. Furthermore, it decreases with increasing workpiece interface stiffness and increasing adhesive joint thickness following a power law relationship. It is believed that necking within the adhesive joint has a significant influence on this relationship. For stiff workpiece interfaces, residual tensile forces can grow larger than 25% of the tensile break strength of an adhesive joint formed without restraint.

scholarly journals Cable Tensile Forces Associated to Winch Design in Tethered Harvesting Operations: A Case Study from the Pacific North West

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 827
Author(s):  
Omar Mologni ◽  
Eric D. T. Nance ◽  
C. Kevin Lyons ◽  
Luca Marchi ◽  
Stefano Grigolato ◽  
...  
Keyword(s):  
Endurance Limit ◽  
Tensile Force ◽  
Force Analysis ◽  
North West ◽  
The Pacific ◽  
Work Tasks ◽  
Tensile Forces ◽  
System Activation ◽  
The Impact

Cable tensile forces in winch-assist harvesting have been investigated in order to assess the safety concerns of the technology. However, the literature is lacking, particularly in regards to the impact of winch design. In this study, a Summit Winch Assist tethering a feller-director on ground slopes up to 77% was monitored for four days. The cable tensile forces were simultaneously recorded at the harvesting and anchor machine at a frequency of 100 Hz. Cameras and GNSS devices enabled a time study of the operations and the recording of machine positions. Winch functionality and design were disclosed by the manufacturer and used for the interpretation of the results. The cable tensile forces reached 296 kN at the harvesting machine and 260 kN at the anchor machine. The slow negotiation of obstacles while moving downhill recorded the highest peaks, mainly due to threshold settings of the winch in the brake system activation. Lower but significant peaks were also recorded during stationary work tasks. The peaks, however, were limited to a few events and never exceeded the endurance limit of the cable. Overall, the study confirmed recent findings in cable tensile force analysis of active winch-assist operations and provided evidence of the underlaying mechanisms that contribute to cable tensile forces.

Study on Mechanical Behavior of Steel Plate Support with Oval Bolt Hole in Space Frame Structure under Combined Action of Shear Force and Tensile Force

2013 ◽  
Vol 351-352 ◽  
pp. 367-371
Author(s):  
Meng Hong Wang ◽  
Yuan Ying He ◽  
Yan Chen
Keyword(s):  
Steel Plate ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Tensile Force ◽  
Frame Structure ◽  
Bottom Plate ◽  
Lateral Stiffness ◽  
Support Design ◽  
Bolt Holes ◽  
The Impact

The way of pre-reserving oval bolt hole in steel plate support design in space grid structure so that it can provide lateral stiffness for the structure is a common practice. However, the details about this plate support cant be found in related codes. As a result, what effect this kind bolt hole could influence on the mechanical performance of the support needs to be further studied. In order to solve this problem, a common used plate support with oval bolt holes is discussed. The contact between the bolt and the hole, the bolt cap and the plate, the bottom plate and the base plate is established respectively with the ABAQUS/Standard, which is to analysis the impact of the oval bolt holes on the load capacity and lateral stiffness of the steel plate support.

scholarly journals Determination of the Impact of Weft Density on Fabric Dynamic Thickness under Tensile Forces

2019 ◽  
Vol 27 (6(138)) ◽  
pp. 46-53
Author(s):  
Željko Penava ◽  
Diana Šimić Penava ◽  
Željko Knezić
Keyword(s):  
Axial Strain ◽  
Tensile Force ◽  
Woven Fabric ◽  
Uniaxial Tensile ◽  
Measuring Apparatus ◽  
Thickness Change ◽  
Fabric Thickness ◽  
Axial Forces ◽  
Tensile Forces ◽  
The Impact

This paper deals with the impact of fabric density on fabric thickness change when samples are subjected to uniaxial tensile forces in the weft direction. During stretching, fabric thickness changes depending on the value of the tensile force. In an effort to be as precise as possible in measuring fabric dynamic thickness changes and the area on which the tensile force acts, a new measuring apparatus was designed and constructed. This measuring apparatus allows the simultaneous measurement of fabric dynamic thickness, related tensile axial forces and extension. Measurements of the fabric dynamic thickness, breaking force and breaking extension during the stretching process were carried out on five samples of cotton woven fabric with a constant warp density and different weft densities in the same structural plain weave. Based on the experimentally obtained values, the paper presents diagrams of the relationship between dynamic changes in fabric thickness in relation to the tensile force and extension. The research presented in this paper shows that an increase in the tensile force increases fabric thickness for all weft densities. Also, the out-of-plane woven fabric ratio was calculated as a relation between the relative thickness strain and relative axial strain. The characteristic curve shows this ratio.

Restriction of nyctinastic movements and application of tensile forces to leaves affects diurnal patterns of expansion growth

2002 ◽  
Vol 29 (11) ◽  
pp. 1247 ◽  
Author(s):  
Achim Walter ◽  
Regina Feil ◽  
Ulrich Schurr
Keyword(s):  
Ricinus Communis ◽  
Leaf Growth ◽  
Starch Content ◽  
Tensile Force ◽  
Soluble Sugars ◽  
Leaf Expansion ◽  
Leaf Vein ◽  
Tensile Forces ◽  
Biomechanical Forces ◽  
The Impact

Leaves of Ricinus communis L. show strong nyctinastic movements as well as diurnal variations of growth activity, combined with prominent basipetal gradients of relative growth rate. A novel technique, using digital image sequence processing, is able to resolve such spatio–temporal patterns of leaf growth with high resolution. In this paper we analyse the impact of prevention of nyctinastic movements, and the potential of tensile forces to overcome the retarding effects. Tensile forces affected leaf expansion and tissue expansibility in a dose–response relation. In a comparison with freely-growing leaves, an appropriate, optimal tensile force was identified that rebuilt the natural diurnal course of leaf expansion. With this tensile force, undisturbed patterns of temporal and spatial growth distribution as well as undisturbed concentrations of major cations, amino acids or soluble sugars were observed. However, diurnal fluctuations in starch content of almost fully-grown leaves were affected by the treatment and could not be compensated by tensile forces. This effect might point to a connection between diurnal growth variations of the leaf vein, biomechanical forces that synchronize growth within the vein, and metabolism of carbohydrates as growth substrates of the vein. We therefore hypothesize that interveinal tensions, which are produced during nyctinastic leaf movements, are (i) required for undisturbed leaf growth and (ii) can be simulated by application of adequate tensile forces.

scholarly journals Rigid and Flexible Double Shear Lap Adhesive Joint at Elevated Temperature—An Experimental Study

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2873
Author(s):  
Klaudia Śliwa-Wieczorek ◽  
Bogusław Zając
Keyword(s):  
Elevated Temperature ◽  
Adhesive Joint ◽  
Load Capacity ◽  
Structural Response ◽  
Adhesive Layer ◽  
Visual Assessment ◽  
Epoxy Adhesive ◽  
Shear Tests ◽  
Partial Load ◽  
The Impact

Double lap adhesive connections made of Sika® PS and Monolith EP2579-1 were studied experimentally in shear tests. The destructive shear tests were conducted under a quasi-static load at 20 °C and 80 °C. The aim was to study the impact of elevated temperature on the load capacity of the joint and make a comparative analysis of the results for two types of adhesives: polyurethane Sika® PS (flexible) and epoxy Monolit EP 2579-1 (rigid). The impact of adhesive layer thickness (t = 1, 2 and 4 mm) on the structural response of the joint was tested in two temperature ranges. A distinct impact of the temperature on the joint deformability was noticed. A visual assessment of the joint failure was performed and the initiation and form of failure was described. At 20 °C, the ultimate loading for epoxy adhesive joint depending on the joint thickness (t) was greater than for the polyurethane joint by, respectively, 282% for t = 1 mm, 88% for t = 2 mm and 279% for t = 4 mm. It was proved that the temperature increases to 80 °C in case of both adhesives reduces the mean destructive force in comparison with the measurements made at 20 °C. For the Sika® PS (PUR two-component polyurethane) adhesive, the greatest load capacity decrease was measured for the joint of thickness t = 2 mm (55%), and in case of the epoxy adhesive for the joint of thickness t = 4 mm (89%). It was found that after reaching the destructive force the flexible joints retain a partial load capacity contrary to the rigid joints.

Computer Simulation Technique to Reduce Resulting Residual Stresses and Distortion in High Strength Thin Butt Welded Ship Panels

2008 ◽  
Author(s):  
Moustafa M. El-Afandy ◽  
Moustafa M. El-Gammal ◽  
Ahmed M. Rashwan
Keyword(s):  
Residual Stresses ◽  
Room Temperature ◽  
Welded Joint ◽  
Tensile Force ◽  
High Strength ◽  
The Finite Element Method ◽  
Tensile Forces ◽  
Computer Simulation Technique ◽  
External Forces ◽  
Thin Panel

Welding of thin-plate ship structures often results in warping of finished fabricated panels. Some manufacturers use preheating and/or pre-stressing the plates during assembly or post heating after assembly as a mitigation method to reduce final product distortion with variably satisfactory results. The current paper aims to study the effect of tensile force application (on the plates undergoing welding) on the residual stresses and distortion behaviours of butt welded thin ship panels using the finite element method. The effects on the butt welded thin panel applying several components of different magnitudes of tensile forces before and during welding are shown. Those external forces are released after the welded joint has reached the room temperature. The stretching force leads to a reduction in the longitudinal residual stresses, and converts part of the tensile components to increase the compressive ones. All those diagnostics will demolish the welded plate distortion making it close to zero.

Influence of social networks on business processes’ development

2020 ◽  
Vol 19 (12) ◽  
pp. 2225-2252
Author(s):  
E.V. Popov ◽  
V.L. Simonova ◽  
O.V. Komarova ◽  
S.S. Kaigorodova
Keyword(s):  
Social Networks ◽  
Social Media ◽  
Business Models ◽  
Business Processes ◽  
Digital Economy ◽  
Theoretical Understanding ◽  
Sales Channels ◽  
A Value ◽  
The Impact

Subject. The emergence of new ways of interaction between sellers and buyers, the formation of new sales channels and product promotion based on the use of digital economy tools is at the heart of improving the business processes. Social networks became a tool for development; their rapid growth necessitates theoretical understanding and identification of potential application in enterprise's business process digitalization. Objectives. We explore the role of social media in the digitalization of business processes, systematize the impact of social networks on business processes of enterprises in the digital economy. Methods. The theoretical and methodological analysis of social networks as a tool for digitalization of company's business processes rests on the content analysis of domestic and foreign scientific studies, comparison, generalization and systematization. Results. We highlight the key effects of the impact of social networks on the business processes of the company; show that the digitalization of business processes should be considered in the context of a value-based approach, aimed at creating a value through the algorithmization of company operations. We determine that social networks are one of the most important tools for digitalization of company's business processes, as they have a high organizational and management potential. We also systematize the effects of social media on company's business processes. Conclusions. We present theoretical provisions of the impact of social networks on business processes of enterprises, which will enable to model and organize ideas about the development of digital ecosystems and the formation of business models.

scholarly journals Determining the Role of Acidity, Fate and Formation of IEPOX-Derived SOA in CMAQ

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 707
Author(s):  
Petros Vasilakos ◽  
Yongtao Hu ◽  
Armistead Russell ◽  
Athanasios Nenes
Keyword(s):  
Significant Influence ◽  
Organic Aerosol ◽  
Liquid Water Content ◽  
Anthropogenic Emissions ◽  
So2 Emissions ◽  
Aerosol Acidity ◽  
A Value ◽  
Future Emission ◽  
The Impact

Formation of aerosol from biogenic hydrocarbons relies heavily on anthropogenic emissions since they control the availability of species such as sulfate and nitrate, and through them, aerosol acidity (pH). To elucidate the role that acidity and emissions play in regulating Secondary Organic Aerosol (SOA), we utilize the 2013 Southern Oxidant and Aerosol Study (SOAS) dataset to enhance the extensive mechanism of isoprene epoxydiol (IEPOX)-mediated SOA formation implemented in the Community Multiscale Air Quality (CMAQ) model (Pye et al., 2013), which was then used to investigate the impact of potential future emission controls on IEPOX OA. We found that the Henry’s law coefficient for IEPOX was the most impactful parameter that controls aqueous isoprene OA products, and a value of 1.9 × 107 M atm−1 provides the best agreement with measurements. Non-volatile cations (NVCs) were found in higher-than-expected quantities in CMAQ and exerted a significant influence on IEPOX OA by reducing its production by as much as 30% when present. Consistent with previous literature, a strong correlation of isoprene OA with sulfate, and little correlation with acidity or liquid water content, was found. Future reductions in SO2 emissions are found to not affect this correlation and generally act to increase the sensitivity of IEPOX OA to sulfate, even in extreme cases.

The influence of Hanok experience on tourists’ attitude and behavioral intention: An interplay between experiences and a Value-Attitude-Behavior model

2021 ◽  
pp. 135676672110117
Author(s):  
Choong-Ki Lee ◽  
Yvette Reisinger ◽  
Muhammad Shakil Ahmad ◽  
Yae-Na Park ◽  
Choong-Won Kang
Keyword(s):  
Behavioral Intention ◽  
Sem Analysis ◽  
Experience Economy ◽  
A Value ◽  
Functional Value ◽  
Experienced Utility ◽  
Attitude Behavior ◽  
Tourism And Hospitality ◽  
The Impact ◽  
Value Functional

This study examines the impact of Hanok experience on tourists’ attitude and behavioral intention using the experience economy ( Pine and Gilmore, 1998 ) and the experienced utility theory ( Kahneman et al., 1997 ). Specifically, the study explores how tourists’ experiences are associated with a Value-Attitude-Behavior (VAB) model in the context of a heritage tourism attraction such as Jeonju Hanok Village in South Korea. A total of 323 responses were examined using SEM analysis. The results revealed that educational, entertainment, and escapism experiences significantly influenced functional value. Functional value had a significant relationship with attitude, which was positively related to behavioral intention. The results indicate the interplay of tourists’ experiences with the VAB model. The study provides theoretical and practical implications for tourism and hospitality academics and practitioners.

Dependency of Machine Efficiency on the Thermal Behavior of Induction Machines

Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Svenja Kalt ◽  
Karl Ludwig Stolle ◽  
Philipp Neuhaus ◽  
Thomas Herrmann ◽  
Alexander Koch ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Electric Vehicles ◽  
Thermal Load ◽  
Load Capacity ◽  
Maximum Load ◽  
Induction Machines ◽  
Electric Machines ◽  
Model Parameters ◽  
Dynamic Operating ◽  
The Impact

The consideration of the thermal behavior of electric machines is becoming increasingly important in the machine design for electric vehicles due to the adaptation to more dynamic operating points compared to stationary applications. Whereas, the dependency of machine efficiency on thermal behavior is caused due to the impact of temperature on the resulting loss types. This leads to a shift of efficiency areas in the efficiency diagram of electric machines and has a significant impact on the maximum load capability and an impact on the cycle efficiency during operation, resulting in a reduction in the overall range of the electric vehicle. Therefore, this article aims at analyzing the thermal load limits of induction machines in regard to actual operation using measured driving data of battery electric vehicles. For this, a thermal model is implemented using MATLAB® and investigations to the sensitivity of model parameters as well as analysis of the continuous load capacity, thermal load and efficiency in driving cycles under changing boundary conditions are conducted.

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