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Notes on rheology

Using Brookfield rotational viscometer to determine viscosity, shear rate (SR) and shear stress (SS):

Viscosity (P) = Shear stress (D/cm^2) / Shear rate (1/cm)

Viscosity (cP) = TK * SMC * 100/RPM * Torque

TK and SMC are pre-determined constants that depend on the type of viscometer and spindle. TK indicates the selected Spring torque constant and SMC which stands for Spindle Multiplier Constant is a value for the spindle utilised. RPM is the set rotational speed for testing and Torque is a value in %. Refer to the Brookfield rotational viscometer manual for more details.

For an LVDV3T model using a ULA type spindle at 30 RPM and a Torque of 90%, TK = 0.09373 and SMC = 0.64 then:

Viscosity (cP) = 0.09373 * 0.64 * 100/30 * 90 = 17.99616 = 18 cP

Shear rate (1/sec) = SRC * RPM

Shear stress (dynes/cm^2) = TK * SMC * SRC * Torque

where SRC is the Shear rate constant and SMC is the Spindle multiplier constant specific to the spindle type. The user only varies the RPM and Torque, whereas, TK, SMC and SRC values are determined by the viscometer.

For those with zero SRC, the shear rate and shear stress can be calculated manually.



For a RVDV-III type viscometer with a SC4-34 spindle set to operate at 30 RPM (corresponding Torque = 62.3%):

Viscosity (cP) = 1 * 64 * 100/30 * 62.3

Shear rate (1/cm) = 0.28 * 30 = 8.4 sec^-1

Shear stress (dynes/cm^2) = 1 * 64 * 0.28 * 62.3 = 1116.42 dynes/cm^2

Calculation of Viscosity, Shear rate and Shear stress for Cylindrical Spindle where SRC = 0, according to the Brookfield More Solutions handbook:

Shear rate (1/cm) = 2 * ω * Rc^2 * Rb^2 / [X^2 * (RC^2 - Rb^2)]

Shear stress (dynes/cm2) = M / (2 *pi * Rb^2 * L)

Viscosity (Poise) = Shear stress (dynes/cm^2) / Shear rate (1/cm)

where ω is the spindle angular velocity (rad/sec) = 2 * pi / 60 * N (rpm), Rc is the radius of measuring container (cm) and must be no greater than 2Rb, Rb is the Spindle radius (cm), X is the radius of fluid affect by spindle rotation (cm), M is the Torque (%) at specific rpm, L is the Spindle length (cm) affecting viscosity measurement.



The table below shows the radius (cm) Rb for Cylindrical Spindle from the Brookfield handbook. M and X can be determined experimentally but is often assumed to be identical to Rb. L is the effective length below.



For a LVDV-II rotational viscometer with LV1 spindle rotating at 30 rpm with a Torque of 80% (assuming that container inner diameter = 3.768 (= 2Rc) and height = 12.01 cm):

ω (rad/sec) = 2 * pi /60 * 30 = 3.142 rad/sec

Shear rate (1/cm) = 2 * 3.142 * 1.884^2 * 0.9421^2 / [0.9421^2 * (1.884^2 - 0.9421^2)] = 8.3793 sec^-1

Shear stress (dynes/cm^2) = 80 / 2 * pi * 0.9421^2 * 7.493 = 1.9145 dynes/cm^2

Viscosity (Poise) = 1.9145 dynes/cm^2 / 8.3793 sec^-1 = 0.2285 Poise = 22.85 cP

What is the difference between DMA and oscillatory shear rheometry?

Q: Seemingly the data, which we get from a DMA and an oscillatory shear rheometer, is similar (storage modulus, loss modulus, etc.) but are these parameters (G', G'', etc.) the same? I am familiar with the oscillatory shear rheometry but not with DMA. Are we also talking about shear deformation with a DMA?

A: They are usually the same, but some DMA fixtures can also make mechanical testings in the normal direction, such as compression or traction tests (for solids). When a DMA gives you G' and G'', they normally come from an oscillatory shear test performed by the DMA setup.
The G', G", etc you get from oscillatory shear rheometry as well as DMA methods are the same. DMA is usually used when the sample material does not flow easily and hence cannot be sheared between surfaces without slippage. In such cases the DMA set up is used. Most rheometers have the capability to perform DMA measurements as well. However, all rheometers cannot perform all the different kinds of DMA measurements necessary for all materials.

Dynes is the force required to accelerate 1 g of mass by 1 cm/sec^2 (g.cm/sec^2 ).

1 Poise = g/cm.sec = 100 centiPoise

1 cP = 0.01 P = 0.001 Pa.s = 1 mPa.s (SI unit) known as dynamic viscosity or absolute viscosity.

Kinematic viscosity (centiStoke, cSt or mm^2/s in SI unit) is calculated for Newtonian fluids by dividing absolute viscosity by fluid density = g/cm.sec / g.cm^3 = cm^2/sec.

1 cSt = 0.01 St = 0.000001 m^2/s = 1 mm^2/s

Kinematic viscosity can be measured using  Canon Glassware Viscometer (ASTM D445/D446, D2170, D2171).



https://m.blog.naver.com/PostList.nhn?blogId=jiny202040
https://www.researchgate.net/post/What_is_the_difference_between_DMA_and_oscillatory_shear_rheometry

Modifying controls parameters in ABAQUS for welding simulation

*CONTROLS option is not needed in most nonlinear analyses, except for use with the parameter ANALYSIS=DISCONTINUOUS. However, if extreme nonlinearities occur, this option may be needed to obtain a solution. 

Reduce solution times by over 70% in a weld modelling problem with little or no change in the precision of results.

In both the thermal and mechanical analyses, save computation time by specifying more iterations per increment to prevent increments being cut-back, as follows:

*CONTROLS, PARAMETERS=TIME INCREMENTATION

** Relax checks on rate of convergence:

** IO   IR   IP   IC   IL   IG

   16 , 18 , 20 , 40 , 30 ,  6

 

Relaxing the convergence tolerances (which incidentally the ABAQUS manual admits are rather tight) as follows:

*CONTROLS, PARAMETERS=FIELD, FIELD=DISPLACEMENT

** ... or *CONTROLS, PARAMETERS=FIELD, FIELD=TEMPERATURE

** Relax solution tolerances:

** R_n^alpha C_n^alpha q_0^alpha q_n^aplha R_p^alpha eps^alpha

     0.02   ,   0.05  ,         ,         ,  0.10   ,

Slacker tolerances give only very small differences in the solution that are insignificant, given the approximations inherent in weld modelling.

Activating the (normally switched off) line search facility can lead to far fewer cut-backs, particularly those arising from:

'***WARNING: THE STRAIN INCREMENT HAS EXCEEDED FIFTY TIMES

    THE STRAIN TO CAUSE FIRST YIELD AT - POINTS'

Activate the line search facility as follows:

*CONTROLS, PARAMETERS=LINE SEARCH

** Nls  Smaxls   Sminls   fsls   etals

    4 ,       ,         ,      ,

Line searching is particularly powerful in the mechanical stress analysis stage of weld modelling where the solution direction is constantly changing. The line search facility obtains a better estimate of the solution at each line search iteration.

For more information see the description of *CONTROLS in the ABAQUS User Manual and the section discussing solution techniques.

Reference

https://www.eng-tips.com/viewthread.cfm?qid=107671

Copy and paste

** CONTROLS

** 

*Controls, reset

** Relax solution tolerances:

** R_n^alpha C_n^alpha q_0^alpha q_n^aplha R_p^alpha eps^alpha

*controls, parameters=field

 0.05, 0.05, , 0.10, 0.05 

** Relax checks on rate of convergence:

** IO   IR   IP   IC   IL   IG 

*Controls, parameters=time incrementation

16, 18, 20, 40, 30, 6, , 50, , , 

*CONTROLS, PARAMETERS=LINE SEARCH

** Nls  Smaxls   Sminls   fsls   etals

    4 ,       ,         ,      ,

F6 배우자 비자 연장 및 외국인 등록

A. 최초 체류기간 연장 및 외국인등록

재외공관(영사관)에서 F6비자(결혼비자)를 발급받고 입국한 경우는 입국 후 3일~90일 사이에 한국인 배우자의 주소지 관할 출입국관리사무소에 외국인 등록 및 체류기간연장서류를 함께 제출 해 신청하면 최대 2년까지 체류가 가능합니다.

단, 입국규제자나 해피스타트프로그램을 이수하지 않은 경우는 최대 1년까지 부여받을 수 있습니다.

F6비자(결혼비자) 체류기간연장서류는 아래와 같습니다.

1. 신청서
2. 여권
3. 여권사진1매
4. 한국인배우자의 혼인관계증명서 및 주민등록등본
5. 체류지입증서류

B. F6비자 외국인등록증 소지자의 체류기간연장

정상적인 혼인상태를 유지하고 있는 경우에만 가능하며, 최대 2년까지 연장이 가능합니다.
단, 자녀가 있을 경우는 최대 3년까지 가능합니다.

F6비자(결혼비자) 체류기간연장서류는 아래와 같습니다. 

1. 신청서
2. 여권
3. 한국인배우자의 혼인관계증명서 및 주민등록등본
4. 체류지 입증서류

체류기간연장은 체류기간 만료전에 신청을 하셔야 합니다.

재외공관(영사관)에서 F6비자(결혼비자)를 발급받았을 때 여권에는 체류기간이 90일입니다. 외국인등록을 하지 않을 경우 F6비자(결혼비자)가 취소되니, 기간을 넘기지 않도록 유의하시기를 바랍니다.

방문 예약 필수 
http://www.hikorea.go.kr

외국인등록사실증명서 발금

출입국 사무소에서 외국인 등록 약 1주일 후 개인별 외국인 등록번호가 부여되며 외국인등록사실증명서를 발급 받을 수 있음. 1345에 전화 걸어서 확인. 출입국·외국인청(출장소), 출입국·외국인사무소 (출장소) 또는 시·군·구·읍·면·동 사무소에서 신청 가능.

1. 발급 신청시 필요 서류: 여권, 수수료 2천원

2. 용도: 휴대폰 및 인터넷 신청, 건강보험 가입 신청, 중고차 구매, 기타

모든 공적인 표기는 한국식인 (성 + 이름)으로 통일. 외국인 등록, 핸드폰 명의 / 통장 / 각종 가입 / 이력서 등등. 외국인등록이 진행된 후로는 신분증이 외국인등록증이 메인이 되며 이 때부터 한국식 이름표기를 주로 사용하게 됩니다. 

Visited Countries

ABAQUS Units

Length: mm

Mass: tonne (T) 

Density: T/mm^3

Time: second

Energy / Work: millijoule (mJ)

Power: milliwatt (= mW = mJ/s)

Force: Newton

Modulus / Stress: N/mm^2 (=MPa)

Temperature: Kelvin (for temperature differentials, 1 K = 1 degree C)

Conductivity: mW/mm/K (= mJ/s/mm/K)

Specific Heat: mJ/T/K

Flux: mW/mm^2 (= mJ/s/mm^2)

Convection: mW/mm^2/K (= mJ/s/mm^2/K)

In a heat transfer analysis it is the product of density and specific heat that is important.  So, as long as consistent mass units are used for the two (and the length, power/energy, and temperature units are consistent with the thermal conductivity and the rest of the model), it should be OK.  So, the following sets of units will both work:

k [W/mm C], rho [kg/mm^3], C [J/kg C]

k [W/mm C], rho [g/mm^3], C [J/g C]

When working with coupled thermal-electric problems it's almost always easiest (and safest) to work with standard SI units (m, kg, sec, N, Volts, Amps, Joules, etc.), because you need to make sure both the thermal and electrical unit systems are consistent.  But, if you really

want to use millimetres for your length scale, the following units should be consistent:

Length -> mm

Density -> g/mm^3

Thermal Conductivity -> W/mm K

Specific Heat -> J/g K

Heat Flux -> W/mm^2

Heat Source -> W/mm^3

Film Coefficient -> W/mm^2 K

Note that energy and power units are Joules and Watts, respectively. You can get away with using grams as the mass unit since only the product of density and specific heat appears in the heat transfer equations, and hence the mass units cancel out.  You couldn't get away with this in a coupled thermal-structural problem - you'd have to use mega-grams.  Assuming potentials are defined in Volts, then the units for current can be derived using the relationship: 

P = iV (i.e., [Watts] = [current units]*[Volts])

Since 1 Watt = 1 Joule/sec, and 1 Volt = 1 Joule/Coulomb, the units of current will be 1 Coulomb/sec, which is an Ampere.

Finally, since V = iR = i*(L/(sigma*A)) (where sigma is the electrical conductivity, L is length, and A is area), the units of electrical conductivity must be Amps/Volt/mm = (Ohm mm)^-1.

Note that the ABAQUS documentation tells you what your units need to be once you've selected the base units (i.e., time, length, etc.).  For example, the documentation for *ELECTRICAL CONDUCTIVITY states that the units must be C T^-1 L^-1 phi^-1:

i.e. Coulomb/second/mm/Volt = Amperes/Volt/mm = (Ohm mm)^-1.

http://abaqus-users.1086179.n5.nabble.com/clarification-needed-on-quot-units-quot-td9492.html

Hosting ABAQUS Floating Licences on a Server

Common-access ABAQUS licenses on cx1 and cx2 are no longer available so the environment variable LM_LICENSE_FILE has to be set to point to the license server containing our own floating licenses and also arrange for those licenses to be hosted on a server. The old ones belonged to a specific research group and were only incidentally used by others. They have now expired and are not going to be renewed. That server can be one of your own, or one managed by ICT (an iclic*.imperial.ac.uk host). 

Looked in the log to see where K12 is obtaining the license from by typing echo LM_LICENSE_FILE and re-using that hostname in the setting of ABAQUSLM_LICENSE_FILE in the cx1 job script gave the following error (주소는 드래그하면 보임):

Cannot connect to license server system.

The license server manager (lmgrd) has not been started yet,

the wrong port@host or license file is being used, or the

port or hostname in the license file has been changed.

Feature:       standard

Server name:   iclic십.cc.아이시에이씨영국

License path:  이칠공공칠@iclic10.cc.아이시에이씨영국

FLEXnet Licensing error:-15,570.  System Error: 115 "Operation now in progress"

Instead, searched the abaquslm_license_file parameter line in a local Abaqus environment file abaqus_v6.env (release 6.14-3 and earlier) or custom_v6.env (release 2016):

abaquslm_license_file="@iclic십사.cc.아이시에이씨영국"

Type export in PuTTY to check LM_LICENSE_FILE. If empty or wrong then type:

export LM_LICENSE_FILE=@iclic십사.cc.아이시에이씨영국

Also, include the above line after module load abaqus/6.14 and intel-suite. It doesn't seem to change when included in the script after the module load so typed it in PuTTY.

To check memory usage:

/apps/memusage/memusage app_name app_param

cp $TMPDIR/memusage.* $PBS_O_WORKDIR

"#PBS -l abaqus_token=12 no longer needed.

When fortran license expires, find the Host ID by typing getmac /v at the Command Prompt to display the value corresponding to the Physical Address for the Ethernet Network Adapter. 

Activate Serial Number using the Host ID and then download the license file which includes the serial number. Copy the file to the location of license file for intel fortran to renew the license.

 C:\Program Files\Common Files\Intel\Licenses