Study of Box Girder Steel Structure Locally Reinforced by CFRP

On the basis of using CFRP (Carbon Fiber Reinforced Polymer) to reinforce steel materials and structures, this paper focused on the reinforcement method of box girder steel structure. Firstly, FEM models were set up to discuss the reinforce method, stress distribution between overall strengthening of flange and locally strengthening. Secondly, typical crack model was raised on the basis of mechanics characteristic, reinforcement effects under different methods was analyzed. The results showed that locally strengthening method to reinforce the certain fatigue areas could improve stress concentration phenomenon and SIF effectively. This paper offered a significant basement for reinforcing box girder steel structures and repairing fatigue cracks using CFRP.

Analysis of Bearing Mechanics Characteristic of Wind Turbine

The transmission gear, bearing and hub and important component of wind field prone to fatigue failure under thermal load and alternating stress. The core component of MW class wind turbine gear box is bearing parts, according to the Betz principle bearing dynamic characteristic is analyzed including deduction and calculation of axial force and radial force, this paper simulates contact stress under the typical conditions of cylindrical roller bearing by finite element method, meanwhile analyzes the stress variation of the rolling body and a holding frame, the simulation results show that bearings bear a greater impact load in the starting process, retainer and rolling body produce large instantaneous stress value in the process, while the stress value is relatively small in the smooth operation and at braking speed, The simulation results has some practical value in engineering of optimization design.

Mechanics Characteristic Research of Human Lumbar Spine Based on the Changed Gradient for 3-D Printer

According to the spinal anatomy data, three-dimensional geometric model of human lumbar spine L3-L5 segment is established in this paper. In the model, the vertebra is divided into cortical bone, cancellous bone, endplate and other structures. The connection between the vertebrae and intervertebral disc is simulated as contact joint. The material properties of lumbar parts of the structure are not the same, the elastic modulus is changing in the analysis. Based on the model, the deformation of the lumbar spine under different size of axial force and lateral torque is simulated. The simulation result shows the variation regularity of the deformation of vertebrae and intervertebral disc under the condition of different pressure. This research provides a quantitative reference for spinal bio-mechanics. The human spine model with a gradient change sets the foundation for processing field of artificial joint using the 3D printing technology.

Mechanics Characteristic Analysis of Support Structure of Shallow-Buried Large-Section Loess Tunnel

To research the mechanics characteristic of support structure of shallow-buried large section loess tunnel with different construction methods, 3D Numerical Simulation is applied and the large-section loess tunnel of highway is taken as an example. Comparing mechanics characteristic of support structure in three types of construction method conditions, the research results show that:The Benching stepping method which caused large surrounding rock deformation can reduce the value of structural performance. While the Both side heading is just opposite.

Research on the Effects of Tires on the Vehicle Handling

It is very important for vehicle handling to match right tires. Mechanics characteristic test is done for the different type tire, the mathematical model is set up according to test data. A dynamic model of vehicle is set up to study the effect of tire performance to vehicle handling stability. Vehicle dynamic response is researched on sinusoidal input of the steering wheel angle. Linear fitting of vehicle dynamic response is done in linear region. According to the difference between the simulation value and linear fitting, different tires are rated.

Testing and Analysis on Dynamic Rheologic Characteristics of Soft Soil under Different Breadth Conditions of Dynamic Loading

The practical investigating and theoretic analysis Indicates that the rheologic action of the soft rock-soil could be accelerated by the dynamic loading, which induces more geotechnical engineering accidents and geologic disasters. The samples of marine deposit soft soil are collected in xiamen, and the dynamic stress-strain, the rheologic strain-time etc rheologic characteristics curves under the different breadth of dynamic loading of sinusoidal variation are tested using dynamic-triaxial device. The rheologic characteristics, rheologic rate and rheologic acceleration varietal process of four different breadths are analyzed. The research results indicate that all the samples are the same varietal process from decelerate rheology, relatively stable rheology to accelerate rheology stage. The dynamic strain slow growth and the rheologic process is relatively stable when the breadth of dynamic loading is low stress ranges of 10~20kPa.When the breadth of dynamic loading exceed 40kPa, the dynamic strain rapid growth and the rheologic is accelerate process till the samples destroy. The research results have academic and actual signification for us to open out the dynamic rheologic mechanics characteristic, explore the accelerating rheologic laws and the rheologic destabilizing dynamic condition of soft rock-soil under dynamic loading.