Strength and Stiffness Optimization of Heavy-Duty Gear

2013 ◽  
Vol 712-715 ◽  
pp. 1701-1704
Author(s):  
Li Yang
Keyword(s):  
Light Weight ◽  
Heavy Duty ◽  
Body Form ◽  
Structure Characteristics ◽  
Frequency Adjustment ◽  
Stiffness Optimization ◽  
Before And After ◽  
Strength And Stiffness

In this paper, a kind of advanced gear body form is proposed, which has the structure characteristics of no weight reducing whole, thin spoke platesthick rim and large fillet. The optimization effect is confirmated by comparative analyzing the structure before and after optimization on strengthstiffnessweight and frequency adjustment performance of gear. The results show that the kind of optimization gear body is suitable for application in aviation, for which has the features of high strengthgood stiffness and light weight and which is easy to adjust gear frequency.

Study on Optimization Design Technique of Aviation Gear Body

2013 ◽  
Vol 376 ◽  
pp. 371-376
Author(s):  
Yan Yan Shi ◽  
Rong Yang ◽  
Xiang Feng Kong ◽  
Mao Qiang Zhang ◽  
Jin Hua Li
Keyword(s):  
Optimization Design ◽  
High Strength ◽  
Light Weight ◽  
Design Technique ◽  
Body Form ◽  
Structure Characteristics ◽  
Frequency Adjustment ◽  
Before And After

In this paper, a kind of advanced gear body form is proposed, which has the structure characteristics of no weight reducing wholethin spoke platesthick rim and large fillet. The optimization effect is confirmated by comparative analyzing the structure before and after optimization on strengthstiffnessweight and frequency adjustment performance of gear. The results show that the kind of optimization gear body is suitable for application in aviation, for which has the features of high strength, good stiffness and light weight and which is easy to adjust gear frequency.

Olfactory Training Using Heavy and Light Weight Molecule Odors

Perception ◽  
2016 ◽  
Vol 46 (3-4) ◽  
pp. 343-351 ◽  
Author(s):  
Sophia C. Poletti ◽  
Elisabeth Michel ◽  
Thomas Hummel
Keyword(s):  
Molecular Weight ◽  
Olfactory Dysfunction ◽  
Light Weight ◽  
Short Term ◽  
Olfactory Loss ◽  
Short Term Exposure ◽  
Before And After ◽  
Phenyl Ethyl Alcohol ◽  
A Prospective Study ◽  
Olfactory Training

Background Repeated short-term exposure to odors is known to improve olfaction in patients with acquired olfactory dysfunction. The aim was to find out whether differences in molecular weight of odors used for olfactory training influences olfaction. We hypothesized a greater improvement following training with light weight molecule (LWM) odors. Methods A prospective study was performed in patients with posttraumatic (PTOL) and postviral olfactory loss (PVOL). Olfactory training was performed over a period of 5 months. One group ( n = 48) used four odors containing heavy weight molecules (HWM; >150 g/mol) and another ( n = 48) containing LWM (<150 g/mol). Olfaction was tested before and after the training using the Sniffin’ Sticks test. Results Olfactory training was associated with olfactory improvement, with the improvement in PVOL patients being three times greater than that seen in the PTOL group. Compared with LWM training, HWM training was associated with a significantly greater improvement in Phenyl Ethyl Alcohol (PEA) threshold scores in PVOL patients; however, no such improvement could be shown for other subtests or in PTOL patients. Conclusion Overall, training was associated with olfactory improvement. With the exception of threshold scores in PVOL, there were no significant differences between LWM and HWM groups.

scholarly journals Coupling characteristics of meso-structure and thermophysical parameters of deep granite under high geo-temperature

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4621-4629
Author(s):  
Huan Wang ◽  
Shuang You ◽  
Hong-Guang Ji ◽  
Hui-Ci Xu ◽  
Qi Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermal Constant ◽  
Structure Characteristics ◽  
Thermophysical Parameters ◽  
Before And After ◽  
Coupling Characteristics ◽  
Granite Samples

Polarizing microscope, nuclear magnetic resonance, and thermal constant analyzer were used to test the granite samples in the depth of 1500-2000 m in San?shandao before and after the heat treatment and be carried out to study the cor?responding relationship between rock meso-structure characteristics and different geothermal temperature circumstances, and the influence of thermal cycling on rock meso-structure. Tests results present that the porosity, pore size distribution, thermal conductivity and specific heat capacity are significantly affected by the environment where the rock occurs, mineral composition and particle size, and the increase in porosity and water content will cause the thermal conductivity and specific heat capacity to decrease.

scholarly journals Curable Area Substantiation of Self-Healing in Concrete Using Neutral Axis

2019 ◽  
Vol 9 (8) ◽  
pp. 1537 ◽  
Author(s):  
Choonghyun Kang ◽  
Taewan Kim
Keyword(s):  
Neutral Axis ◽  
The Self ◽  
Strain Gauges ◽  
Self Healing ◽  
Distinct Area ◽  
Before And After ◽  
Strength And Stiffness ◽  
Underlying Mechanisms ◽  
Healing Assessment ◽  
Physical Recovery

The self-healing nature of concrete has been proved in many studies using various methods. However, the underlying mechanisms and the distinct area of self-healing have not been identified in detail. This study focuses on the limits of the area of self-healing. A bending specimen with a notch is used herein, and its flexural strength and stiffness before and after healing are compared and used for self-healing assessment. In addition, the neutral axis of the specimen was measured using successive strain gauges attached to the crack propagation part. Although the strength and stiffness of the concrete recovered after self-healing, the change in the location of the neutral axis before and after healing was insignificant, which indicates that physical recovery did not occur for once-opened crack areas.

Occurrence and Prevention of Changes in the Chemical Structure of Natural Rubber Tire Tread Vulcanizates during Service

1970 ◽  
Vol 43 (5) ◽  
pp. 1215-1224 ◽  
Author(s):  
J. I. Cunneen ◽  
R. M. Russell
Keyword(s):  
Chemical Structure ◽  
Main Chain ◽  
Heavy Duty ◽  
Structural Alterations ◽  
The Road ◽  
Rubber Tire ◽  
Before And After ◽  
On The Road ◽  
The Stability ◽  
Made In

Abstract The chemical structure of the tread vulcanizate of heavy-duty tires has been investigated before and after service on the road, and after testing under conditions designed to induce tread-lift. Significant changes occurred. These included a marked reduction in the concentration of polysulfide crosslinks, and an increase in the amount of monosulfide crosslinks and main chain modification. Experiments with vulcanizates made in the laboratory indicated that the structural alterations in the tires were due to thermal anaerobic reactions caused by heat build-up, and that they resulted in a deterioration in some of the physical properties of the tread vulcanizate. The rate of desulfuration of ‘model’ polysulfides has been found to depend critically upon the nature of the vulcanization recipe. These novel findings point the way to improving the stability of vulcanizates used in the treads of tires and, consequently, tire performance.

scholarly journals Effect of cotton padding on the setting properties of plaster slabs

2013 ◽  
Vol 95 (2) ◽  
pp. 107-109 ◽  
Author(s):  
D Barlow ◽  
R Bansal ◽  
T Barlow ◽  
SJ Rhee ◽  
JH Kuiper ◽  
...  
Keyword(s):  
Water Content ◽  
Water Immersion ◽  
Testing Machine ◽  
Materials Testing ◽  
Optimal Position ◽  
Three Point Bending ◽  
Before And After ◽  
Plastic Cylinder ◽  
Strength And Stiffness ◽  
American Society

Introduction Plaster of Paris (PoP) impregnated bandages have been used to maintain the position of bones and joints for over a century. Classically, wool dressing is applied to the limb before the PoP, which can then be moulded to the desired shape. A modification of this practice is to wrap the PoP bandages circumferentially in cotton before wetting and applying to the patient in an attempt to reduce inhalation of plaster dust and reduce mess. However, this may affect the water content of the cast and therefore also its setting properties and strength. This study compared the setting properties of PoP casts when used with and without cotton wrapping. Methods Sixty specimens, compliant with the American Society for Testing and Materials standards for three-point bending tests, were prepared, with thirty wrapped in cotton. All were weighed before and after water immersion, and wrapped around a plastic cylinder to mimic limb application. Bending stiffness and yield strength was measured on a servohydraulic materials testing machine at 2, 6, 12, 24, 48 and 72 hours. Results The water content of cotton-wrapped plaster was significantly higher (50%) than that of standard plaster. It had significantly lower strength up to 24 hours and significantly lower stiffness up to 72 hours. Conclusions The initial decrease in strength and stiffness of the cast wrapped in cotton may comprise the ability of the backslab to hold the joint or bone in an optimal position. Any modification of the standard plaster slab application technique should allow for the potential adverse effects on the plaster setting properties.

Hydroformability of Bulge Forming Light-Weight Tubes via Micro-Hardness Dependence

2011 ◽  
Vol 465 ◽  
pp. 149-152
Author(s):  
G.D. Wang ◽  
Luen Chow Chan
Keyword(s):  
Vickers Hardness ◽  
Tube Hydroforming ◽  
Hardness Measurement ◽  
Light Weight ◽  
Micro Hardness ◽  
Forming Process ◽  
Material Hardness ◽  
Before And After ◽  
Hardness Values ◽  
Tubular Components

To evaluate the hydroformablility of tubular components in the tube hydroforming (THF) process, the conventional method is to measure the deformed square or circle grids printed on the surface of the tubular parts. However, the reliability of those measured data is affected greatly by the grid size and its measurement method on the curved surface. It is well-known that material hardness varies under different plastic deformation conditions, especially before and after the forming process. And it is more convenient to obtain the Vickers’ hardness values and distribution around the burst area of deformed components. This paper mainly presents an effective and reliable approach to evaluate the hydroformability of tubular components using micro-hardness measurement. At first, the Vickers’ hardness values and distribution around the burst area of the deformed components were obtained. The plastic strain, together with its distribution in such an area could then be derived by the measured micro-hardness through the developed equations. As a result, it was found to be more suitable to evaluate the hydroformability of tubes using this approach instead of the traditional grids measurement.

Static Stiffness Optimization of Large Ram Based on Equivalent Elastic Modulus

2014 ◽  
Vol 621 ◽  
pp. 9-18 ◽  
Author(s):  
Feng He Wu ◽  
Xiao Peng Xu ◽  
Jun Wang ◽  
Jun Wei Fan
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Large Scale ◽  
Optimization Procedure ◽  
Element Model ◽  
Heavy Duty ◽  
Static Stiffness ◽  
Stiffness Optimization ◽  
Finite Element Technology ◽  
Bending Load

The finite element model of heavy-duty machine tool’s ram components has a large number of elements, many contact pairs for assembly and a large-scale optimization calculation, which make the optimization difficult to conduct. To solve this problem, a static stiffness optimization method of the large component based on the equivalent elastic modulus is put forward. The proposed method is applied to super-heavy-duty CNC floor-type milling and boring machine of TK6932 as a case study. Based on the principle of the equivalent stiffness, the ram assembly with complex constraints and contacts is equivalent to a ram part without other components, the calculation method of the equivalent elastic modulus is analyzed and the equivalent elastic modulus formula of the ram under the bending load is derived. Taking the four box-walls’ thickness and the three stiffened-plates’ thickness of the ram as the optimization variables, the minimal volume under static loading as the target and the maximal displacement and stress as the constraints, the optimized mathematical model of the ram’s equivalent static stiffness is established. The results of the optimization are rounded according to the sensitivity analysis. Besides, the optimization effect is proved by simulation through the finite element technology. The optimization procedure and results show that the simplified method based on equivalent elastic modulus presented in the paper can control the calculation scale effectively, and ensure the process of the optimization smooth.

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