Question

Title: Titanium Alloy Database
Table: Table 5b. Creep and Stress Rupture Properties of Titanium Alloys - Stress for Creep Extension & Rupture (Metric Units)
	alloy type	common alloy name	alloy alias	ASTM grade	UNS no.	condition	product form	product thickness (mm)	test temperature (°C)	rupture time (s)	stress to produce 0.1% strain (MPa)	stress to produce 0.2% strain (MPa)	stress to produce 0.5% strain (MPa)	stress to produce 1.0% strain (MPa)	stress to produce 2.0% strain (MPa)	stress to produce 5.0% strain (MPa)	rupture stress (MPa)	notes	source
	Unalloyed & Modified Titanium	Unalloyed Gr. 1	CP Grade 1	1	R50250	A	NR	NR	93	10000							193		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 1	CP Grade 1	1	R50250	A	NR	NR	150	10000							166		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 1	CP Grade 1	1	R50250	A	NR	NR	205	10000							145		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 1	CP Grade 1	1	R50250	A	NR	NR	260	10000							138		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 1	CP Grade 1	1	R50250	A	NR	NR	315	10000							124		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 2	CP Grade 2	2	R50400	A	NR	NR	93	10000							262		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 2	CP Grade 2	2	R50400	A	NR	NR	150	10000							228		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 2	CP Grade 2	2	R50400	A	NR	NR	205	10000							200		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 2	CP Grade 2	2	R50400	A	NR	NR	260	10000							179		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 2	CP Grade 2	2	R50400	A	NR	NR	315	10000							159		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	27	10	275			331		400	448		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	27	100	214	241		290	310	366	428		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	27	1000			221	234		317	400		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	425	10	34	55	69	90	117	138	152		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	425	100	28	34	48	55	69	83	110		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	425	1000				28	31	34	62		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	540	10	17	21	26				48		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	540	100	7	10	17				33		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 3	CP Grade 3	3	R50550	A	NR	NR	540	1000			7				19		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	25	10			366	393	428	490	531		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	25	100			338	345	366	428	497		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	25	1000			255	283	310	359	462		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	370	1	186	207		228			234		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	370	10	152	186	214	221	228		228		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	370	100	124	145	172	193	214	228	221		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	370	1000		97	110	124	138	159	179		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	425	1	117	138	172	207	221	221	221		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	425	10	69	90	124	145	159	179	193		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	425	100	62	55	76	90	97	117	138		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	425	1000			41	48	55	69	90		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	540	10	7	22	28	33	38	48	69		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	540	100			21		26	35	52		ASM
	Unalloyed & Modified Titanium	Unalloyed Gr. 4	CP Grade 4	4	R50700	A	NR	NR	540	1000			16				36		ASM
	Unalloyed & Modified Titanium	Ti-Ni-Mo	CP Grade 12	12	R53400	A	NR	NR	250	1000				221			297		ASM
	Alpha & Near-Alpha	Ti-3Al-2.5V	Ti Grade 9	9	R56320	A	NR	NR	250	1000				400			421		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	400	10	607	621					917		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	400	100	517	572					910		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	400	1000	414	483					876		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	450	10	359	428					835		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	450	100	248	310					821		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	450	1000	138	193					655		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	500	10	172						662		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	500	100	90						517		ASM
	Alpha-Beta	Ti-4Al-4Mo-2Sn	Ti-550, IMI			NR	bar	NR	500	1000	28						241		ASM
	Alpha-Beta	Ti-6Al-4V	Titanium Grade 5; Ti-6-4	5	R56400	A	NR	NR	400	100	276	331	483	524		635	662		ASM
	Alpha-Beta	Ti-6Al-4V	Titanium Grade 5; Ti-6-4	5	R56400	A	NR	NR	400	1000			407	455		579	614		ASM
	Alpha-Beta	Ti-6Al-4V	Titanium Grade 5; Ti-6-4	5	R56400	A	NR	NR	455	10	262	317	393	441		559	600		ASM
	Alpha-Beta	Ti-6Al-4V	Titanium Grade 5; Ti-6-4	5	R56400	A	NR	NR	455	100	124	172	255	303		414	483		ASM
	Alpha-Beta	Ti-6Al-4V	Titanium Grade 5; Ti-6-4	5	R56400	A	NR	NR	455	1000			124	166		276	366		ASM
	Alpha-Beta	Ti-6Al-4V	Titanium Grade 5; Ti-6-4	5	R56400	STA	NR	NR	400	10	462	524	586	621		662	703		ASM
			From the data you have just downloaded, try to predict the stress at which Ti-11.5Mo-6Zr-4.5Sn will fail at if it needs to last for 750hrs at 370°C. (Yes, you might need to draw a graph). Draw the graph and explain your answer

Answer 1

Here the shared variable is counter. When multiple threads try to access and increment it, it causes race condition and the value doesn't increase as expected.

We can use Mutex(Mutual exclusion) method or semaphores to solve this problem. Here we will use Mutual Exclusion to solve this problem.

The mutex class is a synchronization primitive that can be used to protect shared data from being simultaneously accessed by multiple threads.

This is the final answer:

//
// Created by Yash on 11/29/2018.
//

#include <iostream>
#include <thread>
#include <mutex>

using namespace std;

std::mutex mu;

int counter;

void increment()
{
    mu.lock();
    counter++;
    mu.unlock();
}

int main()
{
    counter =0;
    cout << "The value in counter is : " << counter << endl;

    thread tarr[30000];
    for (int i =0; i < 30000; i++)
        tarr[i] = thread(increment);
    for (int i =0; i < 30000; i++)
        tarr[i].join();

    cout << "After running 30,000 threads ";
    cout << "the value in counter is : " << counter << endl;
    return 0;
}

-------------------------------------------

You can use this code that tests what the question has asked to do 50 times and everytime the answer is 30000:

//
// Created by Yash on 11/29/2018.
//

#include <iostream>
#include <thread>
#include <mutex>

using namespace std;

std::mutex mu;

int counter;

void increment()
{
    mu.lock();
    counter++;
    mu.unlock();
}

int test()
{
    counter =0;
    cout << "The value in counter is : " << counter << endl;

    thread tarr[30000];
    for (int i =0; i < 30000; i++)
        tarr[i] = thread(increment);
    for (int i =0; i < 30000; i++)
        tarr[i].join();

    cout << "After running 30,000 threads ";
    cout << "the value in counter is : " << counter << endl;
}
int main()
{
    for(int t=0; t<50; t++)
    {
        test();
    }
    return 0;
}

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